Sebaceous Epithelial-Myoepithelial Carcinoma of the Parotid gland: A case report of a new histologic variant Gustav St˚alhammar M.D., G¨oran Elmberger M.D., PhD. PII: DOI: Reference:
S1092-9134(14)00049-5 doi: 10.1016/j.anndiagpath.2014.04.004 YADPA 50935
To appear in:
Annals of Diagnostic Pathology
Received date: Accepted date:
28 April 2014 28 April 2014
Please cite this article as: St˚ alhammar Gustav, Elmberger G¨oran, Sebaceous EpithelialMyoepithelial Carcinoma of the Parotid gland: A case report of a new histologic variant, Annals of Diagnostic Pathology (2014), doi: 10.1016/j.anndiagpath.2014.04.004
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT Title page Sebaceous Epithelial-Myoepithelial Carcinoma of the Parotid gland: A case report of a
RI P
T
new histologic variant. Gustav Stålhammar1,2 M.D.
SC
Göran Elmberger3 M.D. PhD.
MA NU
From St. Erik Eye Hospital1, Department of Oncology and Pathology2 at Karolinska Institutet, Stockholm, Sweden and Department of Clinical Pathology3, Örebro University
ED
Hospital, Örebro, Sweden.
Corresponding author: Gustav Stålhammar M.D.
AC
CE
Phone: 0046-8-6723000
PT
Email: [email protected]
1
ACCEPTED MANUSCRIPT Abstract and Key Words Abstract: Epithelial-myoepithelial carcinoma (EMCa) is a double-cell layered low grade
T
malignant tumor, representing approximately 1 % of all salivary gland tumors 1 2 3. Its
RI P
histological characteristic is that of an inner layer of cuboidal epithelial cells with dense granular cytoplasm and central or basal rounded nucleus, and an outer layer of clear,
SC
polygonal myoepithelial cells, together forming ductal structures in a lobulated papillary or
MA NU
cystic pattern. Although solid components of clear cells is not uncommon, and squamous differentiation, spindle cells and oncocytic appearance is a well-documented histologic feature of EMCa, sebaceous differentiation as a precise histologic variant has to our knowledge only been suggested by Shinozaki et al in 2008 4. In this report, we present a case
ED
of a carcinoma of the parotid gland in a 59-year old female patient, with an immunophenotype supporting the proposed entity of sebaceous epithelial-myoepithelial
PT
carcinoma.
CE
Key Words: Sebaceous Epithelial-Myoepithelial carcinoma, Epithelial-Myoepithelial
AC
carcinoma, Parotid gland, Salivary glands. Suggested running head: Sebaceous EMCa
2
ACCEPTED MANUSCRIPT Text
T
INTRODUCTION
RI P
Salivary gland carcinomas comprise a diverse and challenging minority of head and neck malignancies 1 5. Currently, WHO lists 41 malignant and benign variants in their histological
SC
classification of primary tumors of the salivary glands. Of these, 24 are recognized as malignant epithelial tumors with a wide range in prognosis 1. As histological tumor grade is
MA NU
one of the most important predictors of outcome 1 3 4 6 7 8, general categories of high grade lesions with roughly 40 % 5-year survival to low grade lesions with 85-90 % 5-year survival can be identified 1. After a stratification of this nature, Epithelial-Myoepithelial carcinoma
ED
would be sorted to the latter category.
Although increasing the number of histological variants and the diversity of this group
PT
of tumors is not an end in itself, acknowledging distinct entities and thereby making
CE
meaningful classifications possible is. In their 2007 review, Seethala et al 9 reports a sebaceous differentiation in 8 out of 61(13 %) epithelial-myoepithelial tumors, and comment
AC
that this, so far, has not been regarded as part of the morphologic spectrum of EMCa. They do not, however, provide further characterizations or clinicopathologic data of the findings. Shinozaki et al 4 conclude that their findings indicate that sebaceous EMCa is a low grade tumor with comparable prognosis to EMCa, with the obvious reservation that confirmation in much larger series than their 6 cases is required. Note that there are previous observations of EMCa being a tumor with a propensity for locoregional recurrence 1 3 10.
3
ACCEPTED MANUSCRIPT CASE REPORT A 59-year old Caucasian woman came to our attention in May 2013 after being referred from
T
the Department of Head and Neck Surgery, Karolinska University Hospital, Stockholm. The
RI P
patient’s clinical history included a complete hysterectomy for adenocarcinoma of the cervix, a fracture of the olecranon and a recent shingles, now in complete remission. She had during
SC
the previous 2-3 months noted a growing resistance on the left cheek but experienced no pain
MA NU
or other symptoms. A fine needle aspiration biopsy (FNAB) had been conducted at another hospital at the initiative of her general practitioner. The findings were reported to be consistent with an epithelial neoplasia and an immunocytochemical (ICC) assessment of proliferation revealed an (MiB-1) index of 15 %. Blood mixed secretions from the parotid
ED
papilla was the only finding at the initial clinical examination by the Head and Neck surgeon,
PT
besides a confirmation of a palpable elastic resistance with a diameter of 1 cm. Noteworthy is that the patient had sought the attention of her general practitioner as
CE
early as May 2012 for a slight discomfort in the region of the left ear and cheek. This was then regarded as a mild parotitis and the patient was recommended to rinse the mouth with
AC
lemon juice 5 to 6 times daily, after which she sought no further medical assistance in the following year.
A MRI and a new FNAB, this time at our department, were ordered by the Head and Neck surgeon after the initial examination in May 2013. The MRI revealed a contrast absorbing lesion of 1,6 x 1,2 x 1 cm in the left parotid gland and an abnormal dilatation of the parotid duct (figure 1).
4
ACCEPTED MANUSCRIPT Results MICROSCOPIC FINDINGS - CYTOLOGY
RI P
T
With the new FNAB, we concluded that the tumor consisted of two cell populations: One with abundant light cytoplasm containing miniscule vacuoles, and one with an overall oval
SC
shape and scant cytoplasm (figure 2). ICC suggested that the former cell population was negative and the latter positive for p63. Both populations were positive for cytokeratins,
MA NU
CD117 and alpha smooth muscle actin. The findings were reported to support a diagnosis of primary salivary gland tumor, most likely EMCa. A renewed FNAB in June 2013 reinforced this conclusion and reported a MiB-1 index of 25-30 %. An additional X-ray examination of
ED
the chest and a CT-scan of the head, neck and thorax did not add any new information. After these investigations, the patient was admitted for a parotid resection and neck
PT
dissection, including regio 1B, 2A and 3. After receiving the fresh specimen, it was fixated in 10 % phosphate buffered formalin, cut in frontal sections and submitted in its entirety for
CE
histopathological examination. The cut surface of the tumor was whitish, solid and lobulated.
AC
MICROSCOPIC FINDINGS - HISTOPATHOLOGY In the microscope, we found a 3 x 1 x 0,9 cm encapsulated sparsely ductule-forming tumor consisting of two distinct cell populations. The larger ductal epithelial cells, the size of approximately 4-5 lymphocytes, had an abundant cytoplasm, 1-3 round nucleoli and coarse chromatin. The peripheral cell population had an overall oval shape as previously mentioned, the size of approximately 3 lymphocytes and a scant eosinophilic cytoplasm, perceived as a myoepithelial component. The frequency of mitosis was 9 per 10 hpf. The tumor grew intraluminally in the parotid duct and infiltrated the extracapsular fat in a single focus, leaving a 1 mm margin to the cranial resection margin. So far, the entity of a pT3 11
5
ACCEPTED MANUSCRIPT Epithelial-Myoepithelial Carcinoma would be a fitting diagnose to mentioned observations. In this case however, the tumor had further characteristics that called for a more detailed
T
description. Already in H&E staining a third population of sebaceous cells the size of 3-4
RI P
lymphocytes with large cytoplasmatic vacuoles and a nucleus located at the periphery was noticed (figure 3). They were diffusely, still not uniform, distributed over roughly 50 % of the
SC
tumor mass. In some foci they formed aggregations in the center of solid nests of myoepithelial cells, sometimes accompanied by foamy macrophages. In some foci they
sebaceous differentiation (table 1).
MA NU
formed sparser clusters adjacent to the epithelial cells. Immunohistochemistry confirmed the
After making the diagnosis of sebaceous Epithelial-Myoepithelial carcinoma, the
ED
glasses were scanned for digital imaging on a GE Omnyx ™ VL4 scanner (Omnyx LLC, Pittsburgh, PA, USA) and exported from the Omnyx™ Pathologist Work Station for
PT
presentation in this case report.
CE
IMMUNOHISTOCHEMICAL FINDINGS
AC
The results of the immunohistochemical staining are summarized in table 1. Epithelial cells in sebaceous EMCa expressed pan-cytokeratin MNF116 (figure 4) as well as high and low-molecular weight cytokeratins and HER2 (figure 5), whereas myoepithelial and sebaceous cells only expressed cytokeratins to a small degree. We found a diffuse, mainly membranous, staining of ductal epithelial cells with DOG1 (figure 6) and that a proportion was stained moderately with p16. PTEN and Prohibitin was staining both the epithelial and the myoepithelial cell population. PMS2, MSH6 and MLH1 (figure 7) were staining all three cell populations. Androgen showed a nuclear staining of sebaceous cells and a faint and focal cytoplasmatic staining of the epithelial and myoepithelial cell populations interpreted as a non-specific binding to mitochondria (figure 8).
6
ACCEPTED MANUSCRIPT Myoepithelial cells were positive for p63 and Calponin (figure 11). NFP showed an unspecific staining of all three cell populations (figure 12). MSH2 (figure 9) and VIM3B4
T
(figure 10) showed stronger immunoreactivity in the myoepithelial cell population than in the
RI P
epithelial.
SC
Sebaceous cells were strongly positive for EMA (figure 13).
A p53 stain was negative. 27 % of the tumor cells expressed Ki67.
MA NU
FOLLOW UP
In addition to details given above, the patient presented in this case report experienced postoperative transient difficulties to raise the corner of her mouth not extending to a full
ED
facial palsy. She was elected for radiotherapy with 5 fractions per week to a total of 64 Gy. An oncologist determined that there was no indication for concomitant Cisplatin. During
PT
radiotherapy the patient experienced local pain in the irradiated area, which was treated with
CE
Paracetamol and Codeine. Just before completion of the radiotherapy, she suffered from intermittent monocular blurred vision. An ultrasound of her carotid arteries was performed in
AC
fear of this being embolic Amaurosis fugax. It was however determined that she suffered from Iritis, a condition that relapsed 5 months later. 10 months post surgery and 6 months after completion of the radiotherapy the patient did not need any analgesics, was working full time and complaining of no other symptoms than slight tiredness and low salivary production. A clinical examination and a pharyngolaryngeal fiberoscopy gave no suspicions of tumor relapse.
7
ACCEPTED MANUSCRIPT Discussion EMCa is a low grade malignant tumor of the salivary glands. The characterization of a novel
T
variant with sebaceous differentiation offers a challenging and precious opportunity for a
RI P
deepened understanding of the tumor type.
SC
Other recently proposed variants with similar characteristics, posing a pitfall in the process of identification of true Sebaceous Epithelial-Myoepithelial carcinomas, include
MA NU
Oncocytic Sebaceous epithelial-myoepithelial carcinoma, Apocrine Epithelial-Myoepithelial carcinoma, Dedifferentiated Epithelial-Myoepithelial Carcinoma and Clear cell Myoepithelial carcinoma 10 12 13 14.
ED
In this case report, we provide a further immunohistochemical characterization of a Sebaceous Epithelial-Myoepithelial carcinoma, including its immunoreactivity for several
PT
previously unreported low- and high molecular weight cytokeratins. P63, P16, DOG1, PTEN,
depiction.
CE
Prohibin, Androgen, HER2, PMS2, MSH2 and MSH6 as well as a unique cytological
AC
Clinical behavior and impact can however not be determined by morphological and cytological appearance or immunophenotype alone. Neither can significant improvements to the accuracy of present diagnostics, prognosis and predictions be made without an effort to link biological and clinical observations to practical morphological characteristics and biomarkers. Future studies of larger patient groups should therefore seek to clarify the nature of Sebaceous Epithelial-Myoepithelial carcinomas in both an epidemiological and a biological context.
8
ACCEPTED MANUSCRIPT Footnotes Source of Support: Nil
AC
CE
PT
ED
MA NU
SC
RI P
T
Conflict of Interest: None declared
9
ACCEPTED MANUSCRIPT References Barnest, L., Eveson, J., Reichart, P. & Sidransky, D. WHO classification of tumours. Pathology and genetics. Tumours of the head and neck. (2005). 2. Brocheriou, C., Auriol, M., de Roquancourt, A., Gaulard, P. & Fornes, P. [Epithelialmyoepithelial carcinoma of the salivary glands. Study of 15 cases and review of the literature]. Ann Pathol 11, 316-325 (1991). 3. Fonte, D., Aguas, L. N., Alves, L., Sotto-Mayor, C. & Pinto, G. [Epithelialmyoepithelial carcinoma of parotid gland: a tumor of low grade malignancy?]. Acta Med Port 24 Suppl 3, 675-680 (2011). 4. Shinozaki, A. et al. Sebaceous epithelial-myoepithelial carcinoma of the salivary gland: clinicopathologic and immunohistochemical analysis of 6 cases of a new histologic variant. Am J Surg Pathol 32, 913-923 (2008). 5. Seethala, R. R. An update on grading of salivary gland carcinomas. Head Neck Pathol 3, 69-77 (2009). 6. Nagao, T. “Dedifferentiation” and high-grade transformation in salivary gland carcinomas. Head Neck Pathol 7 Suppl 1, S37-S47 (2013). 7. Lima, F. J., Porto, D. E., Cavalcante, J. R., Oka, S. C. & Godoy, G. P. Epithelialmyoepithelial carcinoma of high grade transformation: the case report in the buccal mucosa. Open Dent J 6, 111-117 (2012). 8. Park, J. O., Jung, C. K., Sun, D. I. & Kim, M. S. An unusual presentation of aggressive epithelial-myoepithelial carcinoma of the nasal cavity with high-grade histology. J Laryngol Otol 125, 1286-1289 (2011). 9. Seethala, R. R., Barnes, E. L. & Hunt, J. L. Epithelial-myoepithelial carcinoma: a review of the clinicopathologic spectrum and immunophenotypic characteristics in 61 tumors of the salivary glands and upper aerodigestive tract. Am J Surg Pathol 31, 44-57 (2007). 10. Wang, B. et al. Primary salivary clear cell tumors--a diagnostic approach: a clinicopathologic and immunohistochemical study of 20 patients with clear cell carcinoma, clear cell myoepithelial carcinoma, and epithelial-myoepithelial carcinoma. Arch Pathol Lab Med 126, 676-685 (2002). 11. Compton, C. C. et al. AJCC Cancer Staging Atlas A Companion to the Seventh Editions of the AJCC Cancer Staging Manual and Handbook (Springer New York : Imprint: Springer, New York, NY, 2012). 12. Seethala, R. R., Richmond, J. A., Hoschar, A. P. & Barnes, E. L. New variants of epithelial-myoepithelial carcinoma: oncocytic-sebaceous and apocrine. Arch Pathol Lab Med 133, 950-959 (2009). 13. Seethala, R. R. Oncocytic and apocrine epithelial myoepithelial carcinoma: novel variants of a challenging tumor. Head Neck Pathol 7 Suppl 1, S77-S84 (2013). 14. Baker, A. R. et al. Dedifferentiated epithelial-myoepithelial carcinoma: analysis of a rare entity based on a case report and literature review. Int J Surg Pathol 21, 514-519 (2013).
AC
CE
PT
ED
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SC
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T
1.
10
ACCEPTED MANUSCRIPT Figure and table legends Figure 1: T1 weighted MRI revealing a contrast-absorbing (10 ml gadoteric acid i.v.) lesion
RI P
T
in the left parotid gland. Figure 2: Direct smear Cytology revealed two cell populations. One with abundant light
SC
cytoplasm containing miniscule vacuoles, and one with an overall oval shape and scant cytoplasm.
MA NU
Figure 3: Paraffin section (H&E, 20x) showing 2 distinct epithelial (arrowheads) and myoepithelial (*) cell populations, as well as a third population of sebaceous cells (arrows). Figure 4: Immunhistochemical staining for CkMNF116. Positive immunreactivity highlights
ED
epithelial cells, whereas both myoepithelial and sebaceous cells are stained focally and
PT
weakly.
Figure 5: Epithelial cells, but not myoepithelial or sebaceous, showed membranous
CE
immunreactivity for HER2.
AC
Figure 6: DOG1 staining the epithelial cells diffusely. Figure 7: Nuclei of both the epithelial and myoepithelial cell population were stained by MLH1. Figure 8: The faint staining of Androgen was interpreted as a non-specific binding to mitochondria. Figure 9 and 10: MSH2 and VIM3B4 were showing immunoreactivity in both the epithelial and myoepithelial cell population, somewhat stronger in the former compared to the latter.
11
ACCEPTED MANUSCRIPT Figure 11: Immunohistochemical staining with Calponin. A strong positive staining indicated the myoepithelial cells and a weaker staining the epithelial cells, whilst there was no staining
T
of the sebaceous cells.
RI P
Figure 12: NFP showed strong immunoreactivity in the myoepithelial cells.
SC
Figure 13: EMA highlighted the sebaceous cells.
Table 1: Immunoreactivity for each antibody is described separately according to each
MA NU
respective tumor cell population in the following order: ⁺⁺ equals positive staining in >50 % of tumor cells. ⁺ equals positive staining in 1 – 50 % of tumor cells, – equals positive staining in
S1092-9134(14)00049-5 doi: 10.1016/j.anndiagpath.2014.04.004 YADPA 50935
To appear in:
Annals of Diagnostic Pathology
Received date: Accepted date:
28 April 2014 28 April 2014
Please cite this article as: St˚ alhammar Gustav, Elmberger G¨oran, Sebaceous EpithelialMyoepithelial Carcinoma of the Parotid gland: A case report of a new histologic variant, Annals of Diagnostic Pathology (2014), doi: 10.1016/j.anndiagpath.2014.04.004
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT Title page Sebaceous Epithelial-Myoepithelial Carcinoma of the Parotid gland: A case report of a
RI P
T
new histologic variant. Gustav Stålhammar1,2 M.D.
SC
Göran Elmberger3 M.D. PhD.
MA NU
From St. Erik Eye Hospital1, Department of Oncology and Pathology2 at Karolinska Institutet, Stockholm, Sweden and Department of Clinical Pathology3, Örebro University
ED
Hospital, Örebro, Sweden.
Corresponding author: Gustav Stålhammar M.D.
AC
CE
Phone: 0046-8-6723000
PT
Email: [email protected]
1
ACCEPTED MANUSCRIPT Abstract and Key Words Abstract: Epithelial-myoepithelial carcinoma (EMCa) is a double-cell layered low grade
T
malignant tumor, representing approximately 1 % of all salivary gland tumors 1 2 3. Its
RI P
histological characteristic is that of an inner layer of cuboidal epithelial cells with dense granular cytoplasm and central or basal rounded nucleus, and an outer layer of clear,
SC
polygonal myoepithelial cells, together forming ductal structures in a lobulated papillary or
MA NU
cystic pattern. Although solid components of clear cells is not uncommon, and squamous differentiation, spindle cells and oncocytic appearance is a well-documented histologic feature of EMCa, sebaceous differentiation as a precise histologic variant has to our knowledge only been suggested by Shinozaki et al in 2008 4. In this report, we present a case
ED
of a carcinoma of the parotid gland in a 59-year old female patient, with an immunophenotype supporting the proposed entity of sebaceous epithelial-myoepithelial
PT
carcinoma.
CE
Key Words: Sebaceous Epithelial-Myoepithelial carcinoma, Epithelial-Myoepithelial
AC
carcinoma, Parotid gland, Salivary glands. Suggested running head: Sebaceous EMCa
2
ACCEPTED MANUSCRIPT Text
T
INTRODUCTION
RI P
Salivary gland carcinomas comprise a diverse and challenging minority of head and neck malignancies 1 5. Currently, WHO lists 41 malignant and benign variants in their histological
SC
classification of primary tumors of the salivary glands. Of these, 24 are recognized as malignant epithelial tumors with a wide range in prognosis 1. As histological tumor grade is
MA NU
one of the most important predictors of outcome 1 3 4 6 7 8, general categories of high grade lesions with roughly 40 % 5-year survival to low grade lesions with 85-90 % 5-year survival can be identified 1. After a stratification of this nature, Epithelial-Myoepithelial carcinoma
ED
would be sorted to the latter category.
Although increasing the number of histological variants and the diversity of this group
PT
of tumors is not an end in itself, acknowledging distinct entities and thereby making
CE
meaningful classifications possible is. In their 2007 review, Seethala et al 9 reports a sebaceous differentiation in 8 out of 61(13 %) epithelial-myoepithelial tumors, and comment
AC
that this, so far, has not been regarded as part of the morphologic spectrum of EMCa. They do not, however, provide further characterizations or clinicopathologic data of the findings. Shinozaki et al 4 conclude that their findings indicate that sebaceous EMCa is a low grade tumor with comparable prognosis to EMCa, with the obvious reservation that confirmation in much larger series than their 6 cases is required. Note that there are previous observations of EMCa being a tumor with a propensity for locoregional recurrence 1 3 10.
3
ACCEPTED MANUSCRIPT CASE REPORT A 59-year old Caucasian woman came to our attention in May 2013 after being referred from
T
the Department of Head and Neck Surgery, Karolinska University Hospital, Stockholm. The
RI P
patient’s clinical history included a complete hysterectomy for adenocarcinoma of the cervix, a fracture of the olecranon and a recent shingles, now in complete remission. She had during
SC
the previous 2-3 months noted a growing resistance on the left cheek but experienced no pain
MA NU
or other symptoms. A fine needle aspiration biopsy (FNAB) had been conducted at another hospital at the initiative of her general practitioner. The findings were reported to be consistent with an epithelial neoplasia and an immunocytochemical (ICC) assessment of proliferation revealed an (MiB-1) index of 15 %. Blood mixed secretions from the parotid
ED
papilla was the only finding at the initial clinical examination by the Head and Neck surgeon,
PT
besides a confirmation of a palpable elastic resistance with a diameter of 1 cm. Noteworthy is that the patient had sought the attention of her general practitioner as
CE
early as May 2012 for a slight discomfort in the region of the left ear and cheek. This was then regarded as a mild parotitis and the patient was recommended to rinse the mouth with
AC
lemon juice 5 to 6 times daily, after which she sought no further medical assistance in the following year.
A MRI and a new FNAB, this time at our department, were ordered by the Head and Neck surgeon after the initial examination in May 2013. The MRI revealed a contrast absorbing lesion of 1,6 x 1,2 x 1 cm in the left parotid gland and an abnormal dilatation of the parotid duct (figure 1).
4
ACCEPTED MANUSCRIPT Results MICROSCOPIC FINDINGS - CYTOLOGY
RI P
T
With the new FNAB, we concluded that the tumor consisted of two cell populations: One with abundant light cytoplasm containing miniscule vacuoles, and one with an overall oval
SC
shape and scant cytoplasm (figure 2). ICC suggested that the former cell population was negative and the latter positive for p63. Both populations were positive for cytokeratins,
MA NU
CD117 and alpha smooth muscle actin. The findings were reported to support a diagnosis of primary salivary gland tumor, most likely EMCa. A renewed FNAB in June 2013 reinforced this conclusion and reported a MiB-1 index of 25-30 %. An additional X-ray examination of
ED
the chest and a CT-scan of the head, neck and thorax did not add any new information. After these investigations, the patient was admitted for a parotid resection and neck
PT
dissection, including regio 1B, 2A and 3. After receiving the fresh specimen, it was fixated in 10 % phosphate buffered formalin, cut in frontal sections and submitted in its entirety for
CE
histopathological examination. The cut surface of the tumor was whitish, solid and lobulated.
AC
MICROSCOPIC FINDINGS - HISTOPATHOLOGY In the microscope, we found a 3 x 1 x 0,9 cm encapsulated sparsely ductule-forming tumor consisting of two distinct cell populations. The larger ductal epithelial cells, the size of approximately 4-5 lymphocytes, had an abundant cytoplasm, 1-3 round nucleoli and coarse chromatin. The peripheral cell population had an overall oval shape as previously mentioned, the size of approximately 3 lymphocytes and a scant eosinophilic cytoplasm, perceived as a myoepithelial component. The frequency of mitosis was 9 per 10 hpf. The tumor grew intraluminally in the parotid duct and infiltrated the extracapsular fat in a single focus, leaving a 1 mm margin to the cranial resection margin. So far, the entity of a pT3 11
5
ACCEPTED MANUSCRIPT Epithelial-Myoepithelial Carcinoma would be a fitting diagnose to mentioned observations. In this case however, the tumor had further characteristics that called for a more detailed
T
description. Already in H&E staining a third population of sebaceous cells the size of 3-4
RI P
lymphocytes with large cytoplasmatic vacuoles and a nucleus located at the periphery was noticed (figure 3). They were diffusely, still not uniform, distributed over roughly 50 % of the
SC
tumor mass. In some foci they formed aggregations in the center of solid nests of myoepithelial cells, sometimes accompanied by foamy macrophages. In some foci they
sebaceous differentiation (table 1).
MA NU
formed sparser clusters adjacent to the epithelial cells. Immunohistochemistry confirmed the
After making the diagnosis of sebaceous Epithelial-Myoepithelial carcinoma, the
ED
glasses were scanned for digital imaging on a GE Omnyx ™ VL4 scanner (Omnyx LLC, Pittsburgh, PA, USA) and exported from the Omnyx™ Pathologist Work Station for
PT
presentation in this case report.
CE
IMMUNOHISTOCHEMICAL FINDINGS
AC
The results of the immunohistochemical staining are summarized in table 1. Epithelial cells in sebaceous EMCa expressed pan-cytokeratin MNF116 (figure 4) as well as high and low-molecular weight cytokeratins and HER2 (figure 5), whereas myoepithelial and sebaceous cells only expressed cytokeratins to a small degree. We found a diffuse, mainly membranous, staining of ductal epithelial cells with DOG1 (figure 6) and that a proportion was stained moderately with p16. PTEN and Prohibitin was staining both the epithelial and the myoepithelial cell population. PMS2, MSH6 and MLH1 (figure 7) were staining all three cell populations. Androgen showed a nuclear staining of sebaceous cells and a faint and focal cytoplasmatic staining of the epithelial and myoepithelial cell populations interpreted as a non-specific binding to mitochondria (figure 8).
6
ACCEPTED MANUSCRIPT Myoepithelial cells were positive for p63 and Calponin (figure 11). NFP showed an unspecific staining of all three cell populations (figure 12). MSH2 (figure 9) and VIM3B4
T
(figure 10) showed stronger immunoreactivity in the myoepithelial cell population than in the
RI P
epithelial.
SC
Sebaceous cells were strongly positive for EMA (figure 13).
A p53 stain was negative. 27 % of the tumor cells expressed Ki67.
MA NU
FOLLOW UP
In addition to details given above, the patient presented in this case report experienced postoperative transient difficulties to raise the corner of her mouth not extending to a full
ED
facial palsy. She was elected for radiotherapy with 5 fractions per week to a total of 64 Gy. An oncologist determined that there was no indication for concomitant Cisplatin. During
PT
radiotherapy the patient experienced local pain in the irradiated area, which was treated with
CE
Paracetamol and Codeine. Just before completion of the radiotherapy, she suffered from intermittent monocular blurred vision. An ultrasound of her carotid arteries was performed in
AC
fear of this being embolic Amaurosis fugax. It was however determined that she suffered from Iritis, a condition that relapsed 5 months later. 10 months post surgery and 6 months after completion of the radiotherapy the patient did not need any analgesics, was working full time and complaining of no other symptoms than slight tiredness and low salivary production. A clinical examination and a pharyngolaryngeal fiberoscopy gave no suspicions of tumor relapse.
7
ACCEPTED MANUSCRIPT Discussion EMCa is a low grade malignant tumor of the salivary glands. The characterization of a novel
T
variant with sebaceous differentiation offers a challenging and precious opportunity for a
RI P
deepened understanding of the tumor type.
SC
Other recently proposed variants with similar characteristics, posing a pitfall in the process of identification of true Sebaceous Epithelial-Myoepithelial carcinomas, include
MA NU
Oncocytic Sebaceous epithelial-myoepithelial carcinoma, Apocrine Epithelial-Myoepithelial carcinoma, Dedifferentiated Epithelial-Myoepithelial Carcinoma and Clear cell Myoepithelial carcinoma 10 12 13 14.
ED
In this case report, we provide a further immunohistochemical characterization of a Sebaceous Epithelial-Myoepithelial carcinoma, including its immunoreactivity for several
PT
previously unreported low- and high molecular weight cytokeratins. P63, P16, DOG1, PTEN,
depiction.
CE
Prohibin, Androgen, HER2, PMS2, MSH2 and MSH6 as well as a unique cytological
AC
Clinical behavior and impact can however not be determined by morphological and cytological appearance or immunophenotype alone. Neither can significant improvements to the accuracy of present diagnostics, prognosis and predictions be made without an effort to link biological and clinical observations to practical morphological characteristics and biomarkers. Future studies of larger patient groups should therefore seek to clarify the nature of Sebaceous Epithelial-Myoepithelial carcinomas in both an epidemiological and a biological context.
8
ACCEPTED MANUSCRIPT Footnotes Source of Support: Nil
AC
CE
PT
ED
MA NU
SC
RI P
T
Conflict of Interest: None declared
9
ACCEPTED MANUSCRIPT References Barnest, L., Eveson, J., Reichart, P. & Sidransky, D. WHO classification of tumours. Pathology and genetics. Tumours of the head and neck. (2005). 2. Brocheriou, C., Auriol, M., de Roquancourt, A., Gaulard, P. & Fornes, P. [Epithelialmyoepithelial carcinoma of the salivary glands. Study of 15 cases and review of the literature]. Ann Pathol 11, 316-325 (1991). 3. Fonte, D., Aguas, L. N., Alves, L., Sotto-Mayor, C. & Pinto, G. [Epithelialmyoepithelial carcinoma of parotid gland: a tumor of low grade malignancy?]. Acta Med Port 24 Suppl 3, 675-680 (2011). 4. Shinozaki, A. et al. Sebaceous epithelial-myoepithelial carcinoma of the salivary gland: clinicopathologic and immunohistochemical analysis of 6 cases of a new histologic variant. Am J Surg Pathol 32, 913-923 (2008). 5. Seethala, R. R. An update on grading of salivary gland carcinomas. Head Neck Pathol 3, 69-77 (2009). 6. Nagao, T. “Dedifferentiation” and high-grade transformation in salivary gland carcinomas. Head Neck Pathol 7 Suppl 1, S37-S47 (2013). 7. Lima, F. J., Porto, D. E., Cavalcante, J. R., Oka, S. C. & Godoy, G. P. Epithelialmyoepithelial carcinoma of high grade transformation: the case report in the buccal mucosa. Open Dent J 6, 111-117 (2012). 8. Park, J. O., Jung, C. K., Sun, D. I. & Kim, M. S. An unusual presentation of aggressive epithelial-myoepithelial carcinoma of the nasal cavity with high-grade histology. J Laryngol Otol 125, 1286-1289 (2011). 9. Seethala, R. R., Barnes, E. L. & Hunt, J. L. Epithelial-myoepithelial carcinoma: a review of the clinicopathologic spectrum and immunophenotypic characteristics in 61 tumors of the salivary glands and upper aerodigestive tract. Am J Surg Pathol 31, 44-57 (2007). 10. Wang, B. et al. Primary salivary clear cell tumors--a diagnostic approach: a clinicopathologic and immunohistochemical study of 20 patients with clear cell carcinoma, clear cell myoepithelial carcinoma, and epithelial-myoepithelial carcinoma. Arch Pathol Lab Med 126, 676-685 (2002). 11. Compton, C. C. et al. AJCC Cancer Staging Atlas A Companion to the Seventh Editions of the AJCC Cancer Staging Manual and Handbook (Springer New York : Imprint: Springer, New York, NY, 2012). 12. Seethala, R. R., Richmond, J. A., Hoschar, A. P. & Barnes, E. L. New variants of epithelial-myoepithelial carcinoma: oncocytic-sebaceous and apocrine. Arch Pathol Lab Med 133, 950-959 (2009). 13. Seethala, R. R. Oncocytic and apocrine epithelial myoepithelial carcinoma: novel variants of a challenging tumor. Head Neck Pathol 7 Suppl 1, S77-S84 (2013). 14. Baker, A. R. et al. Dedifferentiated epithelial-myoepithelial carcinoma: analysis of a rare entity based on a case report and literature review. Int J Surg Pathol 21, 514-519 (2013).
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ACCEPTED MANUSCRIPT Figure and table legends Figure 1: T1 weighted MRI revealing a contrast-absorbing (10 ml gadoteric acid i.v.) lesion
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in the left parotid gland. Figure 2: Direct smear Cytology revealed two cell populations. One with abundant light
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cytoplasm containing miniscule vacuoles, and one with an overall oval shape and scant cytoplasm.
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Figure 3: Paraffin section (H&E, 20x) showing 2 distinct epithelial (arrowheads) and myoepithelial (*) cell populations, as well as a third population of sebaceous cells (arrows). Figure 4: Immunhistochemical staining for CkMNF116. Positive immunreactivity highlights
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epithelial cells, whereas both myoepithelial and sebaceous cells are stained focally and
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weakly.
Figure 5: Epithelial cells, but not myoepithelial or sebaceous, showed membranous
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immunreactivity for HER2.
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Figure 6: DOG1 staining the epithelial cells diffusely. Figure 7: Nuclei of both the epithelial and myoepithelial cell population were stained by MLH1. Figure 8: The faint staining of Androgen was interpreted as a non-specific binding to mitochondria. Figure 9 and 10: MSH2 and VIM3B4 were showing immunoreactivity in both the epithelial and myoepithelial cell population, somewhat stronger in the former compared to the latter.
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ACCEPTED MANUSCRIPT Figure 11: Immunohistochemical staining with Calponin. A strong positive staining indicated the myoepithelial cells and a weaker staining the epithelial cells, whilst there was no staining
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of the sebaceous cells.
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Figure 12: NFP showed strong immunoreactivity in the myoepithelial cells.
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Figure 13: EMA highlighted the sebaceous cells.
Table 1: Immunoreactivity for each antibody is described separately according to each
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respective tumor cell population in the following order: ⁺⁺ equals positive staining in >50 % of tumor cells. ⁺ equals positive staining in 1 – 50 % of tumor cells, – equals positive staining in
