British Journal of Dermatology (1990) 123, 757-763.
Pigmented spindle cell naevus L.REQUENA AND E.SANCHEZ YUS Department of Dermatology, University Hospital of San Carlos, Madrid, Spain Accepted for publication 13 June 1990
SUMMARY
We report 22 cases of pigmented spindle cell naevus (PSCN). The usual appearance of these naevi is that of a heavily pigmented papule found mostly on the legs of young patients. Histologically, PSCN was characterized by symmetrical proliferation of spindle-shaped pigmented melanocytes grouped in large junctional nests. Pagetoid spread of single cells in the overlying epidermis was frequently found. In our opinion, PSCN is a distinctive benign acquired melanocytic naevus that in the past has been frequently misdiagnosed as atypical Spitz naevi or malignant melanoma.
Pigmented spindle cell naevus (PSCN) was first described in 1975 by Reed et al.^ This was considered as a distinct variant of the Spitz naevus. The usual clinical appearance of these lesions was of a slightly dome-shaped smooth and heavily pigmented papule. These were generally 3-6 mm in diameter and have a sharp demarcation from the surrounding skin. They mostly occur on the legs of young women. Histologically they are characterized by symmetrical proliferation of spindle-shaped pigmented melanocytes grouped in large nests confined to the dermo-epidermal junction and papillary dermis. So far there have been a number of reports in the literature of PSCN""'' and recently variants have been described."^' It is likely that the condition is not rare and that many cases are misdiagnosed either as malignant melanoma or as Spitz naevi. The purpose of this report is to present the clinical and histopathological findings of 22 cases of PSCN from our institution. In our opinion, this condition can be differentiated from Spitz naevi and from malignant melanoma. METHODS
The cases reported were from the files of the dermatopathology laboratory of our hospital from 1984 to 1989. The clinical details were obtained from either the available notes or from the referring pathologists. At least four sections stained with haematoxylin and eosin were examined for each case and in Correspondence: Dr Luis Requena, C/ Leopoldo Alas Clarin 4-6 F, 28035 Madrid, Spain.
757
758 L.Requena and E.Sanchez Yus several, multiple serial sections were performed on the lesions. The histological findings were evaluated separately by each author and there was good concordance in the scoring. RESULTS
There was a total of 22 lesions from 22 patients (14 female, eight male). The age range of the patients was 5-34 years (mean 16 years). Sixteen of the lesions were on the legs (including buttocks) and six on the arms (including the shoulders) (Fig. i) . In our patients none of the lesions were on the head, neck or trunk. The papules had a characteristic clinical appearance, they were small and varied in diameter from I to 10 mm (mean 4 mm). They were heavily pigmented, slightly dome-shaped tumours that were sharply demarcated from the adjacent normal skin and had a smooth surface (Fig. 2). The history prior to excision varied from 4 months to 17 years (mean 6 years). None of the lesions were described as being present at birth. The suggested clinical diagnosis included malignant melanoma (three cases), dysplastic naevus (eight cases), mclanocytic naevus (eight cases), angiokeratoma circumscriptum (one case) and PSCN (two cases). Histologically, 19 of the 22 lesions (86",,) were junctional naevi and three (14",)) were compound naevi. No entirely intradcrmal naevi were seen. The lateral demarcation was sharp at the margins in all of the lesions. Usually there were well-defined nests of junctional spindle cells (Fig. 3), Twenty of the lesions showed on low power fairly good symmetry, whereas two of the lesions were composed of junctional nests in half of the tumour and isolated spindle cells at the dermo-epidermal junction in the other hau. Juiici:'. lal lentiginous melanocytic hyperplasia was seen in eight of the lesions. The predominant morphology of the cells in all the lesions was spindle-shaped (Fig. 4). Various locations and shapes of nests of naevus cells were found, but the 'round nests' of spindle cells at the bases of the elongated rete ridges were most frequently seen. Occasional bridging was seen in two of the cases. Cytological atypia was not seen and normal
FIGURE I- Lesions of PSCN located predominantly on tbe leg.
Pigmented spindle cell naevus
FIGURE 2. Pigmented lesion on the thigh of a young mate.
FIGURE 3. Sharp lateral demarcation that was presem in all lesions.
759
760
L.Requena and E.Sanchez Yus
FIGURE 4. Spindle cells of the lesions showing abundant melanin bui no atypia.
mitotic figures were seen in only one of the lesions. In the three compound naevi there was a decrease in cell size and the amount of cytoplasm at the base of the lesion. This maturation at the base was evident from the cell size but it remained spindle-shaped. Epidermal invasion by single cells or by small nests was seen in 19 of the cases. This intraepidermal spread was always in the overlying epidermis of the naevus, and there were no solitary melanocytes or nests extending laterally beyond the main component of the tumour. Junctional nests of spindle melanocytic cells were seen in the upper part of the intradermal eccrine duct (Fig. 5) and in the infundibular segment of the hair follicles in the tumour in seven of the lesions. Eosinophilic globules (Kamino bodies} were found in seven lesions at or near the dermo-epidermal junction and in one case these were heavily pigmentcd. Some degree of epidermal hyperplasia was identified in 14 of the lesions, being moderate in 10 and marked in four. In three of the cases there was a rather atrophic epidermis. Nearly all (21 out of 22) had easily identifiable pigment both in the nests of tumour cells and in the overlying epidermis. In the most pigmented lesions there was an abundant amount of melanin in the horny layer and many heavily pigmented macrophages in a band-like arrangement beneath the tumour nests. Varying degrees of inflammatory responses were seen at the base of the lesion in all but one of the cases. These were most marked in six and moderate in 15. A slight lamellar fibroplasia of the papillary dermis was identified in only one of the cases. Some degree of capillary proliferation in the superficial vascular plexus was seen in all but two of the lesions. DISCUSSION
Pigmented spindle cell naevus is a clinicopathological entity that is under-recognized hy dermatologists and dermatopathologists. In a series of cases of PSCN over a period of 5 ^
Pigmenied spindle cell naevus
761
•;
c
L.Requena and E.Sanchez Yus
762
TABLE I. Cases of pigmented spindle cell naevus reported in the literature
Author
Year
Gartmann Sagebiel el al} Sau ei al.''
1981 1984 1984
Schubert" Smith' Kolde et al.
1986 1987 1987 1989
Barnhillw^/.'" This series
Number of cases
Sex of the patients male/female
28
95
9/19 30/60 39/56
8 40
3/5 14/26
91
2
i/i
7
4/3 8/14
22
Age (years)
Site of the lesions
Age range Average age Lower limbs Upper limbs Other areas 4-40 ? 2 5-56 25-3 88 cases in the first four decades of the life 3-50 22 8 2-44 6-24 15 6-39 29 16 5-34
7
9 38
23
12 30
75
3 22 2
4 16
there were only four cases in which the correct diagnosis was previously suggested by the chnicians. In our scries of patients the correct diagnosis was only suspected in two of the 22 cases. However, in all the published reports on PSCN there is a marked similarity in the pathological and clinical features of the cases (Table i). The typical lesion is a small pigmented naevus most frequently located on the legs of young females. Because of the marked pigmentation of the lesion there is often a suspicion that it is a malignant melanoma. The presence of large pigmented spindle cells on histology may frequently lead to the diagnosis of malignant melanoma by the pathologist, who is not aware of this variant of benign melanocytic naevus. The histological features arc quite characteristic and PSCN should be differentiated clearly from malignant melanoma and Spitz naevus. Recently, a variant of PSCN has been reported with features of Spitz naevus"^ in which there were fascicles of plump or slightly cpithclioid spindle cells with the presence of cytological atypia. It is our opinion that lesions such as this should be classified as cases of Spitz naevus with abundant melanin pigmentation. A frequent finding in our series of cases was the pagetoid spread of single cells in the overlying epidermis. This feature in a pigmented melanocytic lesion raises the possibility of a malignant melanoma of the superficial spreading type.'' Intraepidermal sprcadof tumour cells in PSCN is almost always confined to the overlying epidermis with no solitary melanocytes or nests of atypical melanocytes extending laterally beyond the main component of the naevus. In malignant melanoma this pagetoid spread usually extends beyond the lateral margins of the lesion. There is, as yet, little information as to the biological behaviour of PSCN, but so far in the documented cases there have been no reports of metastases."'^ This condition should be regarded as a benign melanocytie naevus. REFERENCES 1 Reed RJ, Ichinose H, Clark WH, Jr, Mihm MC, Jr. Common and uncommon melanocytic nevi and borderline melanomas. Seniin Oncol 1975; 2: 119-47. 2 Sagebiel RW, Chinn EK, Egbert BM. Pigmented spindle cell nevus. Clinical and histological review of 90 cases. Am J Surg Paihol 1984; 8: 645-53, 3 Smith NP. The pigmented spindle cell tumor of Reed; An underdiagnosed lesion. Seiuw Diag Paihol 1987; 4:75-87. 4 Gartmann H. Der pigmentierte Spindelzellentumor (PSC-T). Z Hauikr 1981; s6: 862-76.
Pigmented spindle cell naevus 5 6 7 8
763
Smith NP, Der pigmentierte Spindelzelltumor, Typus Reed. Hauiarzt 1985; 36 CSuppl. VII): 190-2. Schubert E. Der pigmenrierte Spindelzelltumor. Z Hauikr 1986; 61: 827-9. Kolde G, Vakilzadeh F. Der pigmentierte Spindelzellentumor. Haurarzt 1987; 38: 743-5Smith NP, Tbe pigmented spindle cell tumor of Reed. An underrecognised lesion, Br J Dermatol 1983; 109 (Suppl. 24): 39. 9 Sau P, Graham JH, Helwig EB. Pigmented spindle cell nevus. Arch Dermatol 1984; 120: 1615. 10 Barnbill RL, Mihm MC, Jr. Pigmented spindle cell naevus and its variants: distinction from melanoma. Br J Dermatol 1989; 121: 717-26. 11 Kamino H, Ackerman AB. Malignant melanoma in situ: the evolution of malignant melanoma within the epidermis. In: Pathology of Malignant Aielauoma (Ackerman AB, ed). New York: Masson, 1981: 59-81.
Pigmented spindle cell naevus L.REQUENA AND E.SANCHEZ YUS Department of Dermatology, University Hospital of San Carlos, Madrid, Spain Accepted for publication 13 June 1990
SUMMARY
We report 22 cases of pigmented spindle cell naevus (PSCN). The usual appearance of these naevi is that of a heavily pigmented papule found mostly on the legs of young patients. Histologically, PSCN was characterized by symmetrical proliferation of spindle-shaped pigmented melanocytes grouped in large junctional nests. Pagetoid spread of single cells in the overlying epidermis was frequently found. In our opinion, PSCN is a distinctive benign acquired melanocytic naevus that in the past has been frequently misdiagnosed as atypical Spitz naevi or malignant melanoma.
Pigmented spindle cell naevus (PSCN) was first described in 1975 by Reed et al.^ This was considered as a distinct variant of the Spitz naevus. The usual clinical appearance of these lesions was of a slightly dome-shaped smooth and heavily pigmented papule. These were generally 3-6 mm in diameter and have a sharp demarcation from the surrounding skin. They mostly occur on the legs of young women. Histologically they are characterized by symmetrical proliferation of spindle-shaped pigmented melanocytes grouped in large nests confined to the dermo-epidermal junction and papillary dermis. So far there have been a number of reports in the literature of PSCN""'' and recently variants have been described."^' It is likely that the condition is not rare and that many cases are misdiagnosed either as malignant melanoma or as Spitz naevi. The purpose of this report is to present the clinical and histopathological findings of 22 cases of PSCN from our institution. In our opinion, this condition can be differentiated from Spitz naevi and from malignant melanoma. METHODS
The cases reported were from the files of the dermatopathology laboratory of our hospital from 1984 to 1989. The clinical details were obtained from either the available notes or from the referring pathologists. At least four sections stained with haematoxylin and eosin were examined for each case and in Correspondence: Dr Luis Requena, C/ Leopoldo Alas Clarin 4-6 F, 28035 Madrid, Spain.
757
758 L.Requena and E.Sanchez Yus several, multiple serial sections were performed on the lesions. The histological findings were evaluated separately by each author and there was good concordance in the scoring. RESULTS
There was a total of 22 lesions from 22 patients (14 female, eight male). The age range of the patients was 5-34 years (mean 16 years). Sixteen of the lesions were on the legs (including buttocks) and six on the arms (including the shoulders) (Fig. i) . In our patients none of the lesions were on the head, neck or trunk. The papules had a characteristic clinical appearance, they were small and varied in diameter from I to 10 mm (mean 4 mm). They were heavily pigmented, slightly dome-shaped tumours that were sharply demarcated from the adjacent normal skin and had a smooth surface (Fig. 2). The history prior to excision varied from 4 months to 17 years (mean 6 years). None of the lesions were described as being present at birth. The suggested clinical diagnosis included malignant melanoma (three cases), dysplastic naevus (eight cases), mclanocytic naevus (eight cases), angiokeratoma circumscriptum (one case) and PSCN (two cases). Histologically, 19 of the 22 lesions (86",,) were junctional naevi and three (14",)) were compound naevi. No entirely intradcrmal naevi were seen. The lateral demarcation was sharp at the margins in all of the lesions. Usually there were well-defined nests of junctional spindle cells (Fig. 3), Twenty of the lesions showed on low power fairly good symmetry, whereas two of the lesions were composed of junctional nests in half of the tumour and isolated spindle cells at the dermo-epidermal junction in the other hau. Juiici:'. lal lentiginous melanocytic hyperplasia was seen in eight of the lesions. The predominant morphology of the cells in all the lesions was spindle-shaped (Fig. 4). Various locations and shapes of nests of naevus cells were found, but the 'round nests' of spindle cells at the bases of the elongated rete ridges were most frequently seen. Occasional bridging was seen in two of the cases. Cytological atypia was not seen and normal
FIGURE I- Lesions of PSCN located predominantly on tbe leg.
Pigmented spindle cell naevus
FIGURE 2. Pigmented lesion on the thigh of a young mate.
FIGURE 3. Sharp lateral demarcation that was presem in all lesions.
759
760
L.Requena and E.Sanchez Yus
FIGURE 4. Spindle cells of the lesions showing abundant melanin bui no atypia.
mitotic figures were seen in only one of the lesions. In the three compound naevi there was a decrease in cell size and the amount of cytoplasm at the base of the lesion. This maturation at the base was evident from the cell size but it remained spindle-shaped. Epidermal invasion by single cells or by small nests was seen in 19 of the cases. This intraepidermal spread was always in the overlying epidermis of the naevus, and there were no solitary melanocytes or nests extending laterally beyond the main component of the tumour. Junctional nests of spindle melanocytic cells were seen in the upper part of the intradermal eccrine duct (Fig. 5) and in the infundibular segment of the hair follicles in the tumour in seven of the lesions. Eosinophilic globules (Kamino bodies} were found in seven lesions at or near the dermo-epidermal junction and in one case these were heavily pigmentcd. Some degree of epidermal hyperplasia was identified in 14 of the lesions, being moderate in 10 and marked in four. In three of the cases there was a rather atrophic epidermis. Nearly all (21 out of 22) had easily identifiable pigment both in the nests of tumour cells and in the overlying epidermis. In the most pigmented lesions there was an abundant amount of melanin in the horny layer and many heavily pigmented macrophages in a band-like arrangement beneath the tumour nests. Varying degrees of inflammatory responses were seen at the base of the lesion in all but one of the cases. These were most marked in six and moderate in 15. A slight lamellar fibroplasia of the papillary dermis was identified in only one of the cases. Some degree of capillary proliferation in the superficial vascular plexus was seen in all but two of the lesions. DISCUSSION
Pigmented spindle cell naevus is a clinicopathological entity that is under-recognized hy dermatologists and dermatopathologists. In a series of cases of PSCN over a period of 5 ^
Pigmenied spindle cell naevus
761
•;
c
L.Requena and E.Sanchez Yus
762
TABLE I. Cases of pigmented spindle cell naevus reported in the literature
Author
Year
Gartmann Sagebiel el al} Sau ei al.''
1981 1984 1984
Schubert" Smith' Kolde et al.
1986 1987 1987 1989
Barnhillw^/.'" This series
Number of cases
Sex of the patients male/female
28
95
9/19 30/60 39/56
8 40
3/5 14/26
91
2
i/i
7
4/3 8/14
22
Age (years)
Site of the lesions
Age range Average age Lower limbs Upper limbs Other areas 4-40 ? 2 5-56 25-3 88 cases in the first four decades of the life 3-50 22 8 2-44 6-24 15 6-39 29 16 5-34
7
9 38
23
12 30
75
3 22 2
4 16
there were only four cases in which the correct diagnosis was previously suggested by the chnicians. In our scries of patients the correct diagnosis was only suspected in two of the 22 cases. However, in all the published reports on PSCN there is a marked similarity in the pathological and clinical features of the cases (Table i). The typical lesion is a small pigmented naevus most frequently located on the legs of young females. Because of the marked pigmentation of the lesion there is often a suspicion that it is a malignant melanoma. The presence of large pigmented spindle cells on histology may frequently lead to the diagnosis of malignant melanoma by the pathologist, who is not aware of this variant of benign melanocytic naevus. The histological features arc quite characteristic and PSCN should be differentiated clearly from malignant melanoma and Spitz naevus. Recently, a variant of PSCN has been reported with features of Spitz naevus"^ in which there were fascicles of plump or slightly cpithclioid spindle cells with the presence of cytological atypia. It is our opinion that lesions such as this should be classified as cases of Spitz naevus with abundant melanin pigmentation. A frequent finding in our series of cases was the pagetoid spread of single cells in the overlying epidermis. This feature in a pigmented melanocytic lesion raises the possibility of a malignant melanoma of the superficial spreading type.'' Intraepidermal sprcadof tumour cells in PSCN is almost always confined to the overlying epidermis with no solitary melanocytes or nests of atypical melanocytes extending laterally beyond the main component of the naevus. In malignant melanoma this pagetoid spread usually extends beyond the lateral margins of the lesion. There is, as yet, little information as to the biological behaviour of PSCN, but so far in the documented cases there have been no reports of metastases."'^ This condition should be regarded as a benign melanocytie naevus. REFERENCES 1 Reed RJ, Ichinose H, Clark WH, Jr, Mihm MC, Jr. Common and uncommon melanocytic nevi and borderline melanomas. Seniin Oncol 1975; 2: 119-47. 2 Sagebiel RW, Chinn EK, Egbert BM. Pigmented spindle cell nevus. Clinical and histological review of 90 cases. Am J Surg Paihol 1984; 8: 645-53, 3 Smith NP. The pigmented spindle cell tumor of Reed; An underdiagnosed lesion. Seiuw Diag Paihol 1987; 4:75-87. 4 Gartmann H. Der pigmentierte Spindelzellentumor (PSC-T). Z Hauikr 1981; s6: 862-76.
Pigmented spindle cell naevus 5 6 7 8
763
Smith NP, Der pigmentierte Spindelzelltumor, Typus Reed. Hauiarzt 1985; 36 CSuppl. VII): 190-2. Schubert E. Der pigmenrierte Spindelzelltumor. Z Hauikr 1986; 61: 827-9. Kolde G, Vakilzadeh F. Der pigmentierte Spindelzellentumor. Haurarzt 1987; 38: 743-5Smith NP, Tbe pigmented spindle cell tumor of Reed. An underrecognised lesion, Br J Dermatol 1983; 109 (Suppl. 24): 39. 9 Sau P, Graham JH, Helwig EB. Pigmented spindle cell nevus. Arch Dermatol 1984; 120: 1615. 10 Barnbill RL, Mihm MC, Jr. Pigmented spindle cell naevus and its variants: distinction from melanoma. Br J Dermatol 1989; 121: 717-26. 11 Kamino H, Ackerman AB. Malignant melanoma in situ: the evolution of malignant melanoma within the epidermis. In: Pathology of Malignant Aielauoma (Ackerman AB, ed). New York: Masson, 1981: 59-81.
