AMER IC AN JOURNAL OF OT OLA RYNGOLOGY–H E A D A N D NE CK M E D ICI N E AN D S U RGE RY X X (2 0 1 5) XXX –XXX
Available online at www.sciencedirect.com
ScienceDirect www.elsevier.com/locate/amjoto
Spontaneous resolution of a petrous apex cholesterol granuloma☆,☆☆,★ Robert J. Yawn, Alex D. Sweeney, Matthew L. Carlson, George B. Wanna⁎ Department of Otolaryngology–Head and Neck Surgery, Vanderbilt University, Nashville, TN, USA
ARTI CLE I NFO
A BS TRACT
Article history:
Cholesterol granuloma is the most common primary lesion of the petrous apex.
Received 23 October 2015
Management of petrous apex cholesterol granuloma has evolved in recent years from primary surgical treatment to conservative observation. In this article, a case of spontaneous resolution of a petrous apex cholesterol granuloma is described. To the authors’ knowledge, this is the first known report of spontaneous involution of a petrous apex cholesterol granuloma. Radiographic differential diagnosis of petrous apex lesions and the natural history of cholesterol granulomas are discussed. © 2015 Elsevier Inc. All rights reserved.
1.
Introduction
Cholesterol granulomas are the most common primary lesions of the petrous apex, comprising 60% of all pathology arising within this region [1]. A large number of patients are diagnosed incidentally or after obtaining imaging for nonlocalizing headache. Management trends for these lesions have evolved over time, from routine surgery to primary observation with serial imaging. With this trend, natural history data has become increasingly important. Herein we report a case in which spontaneous resolution of a cholesterol granuloma of the petrous apex occurred.
2.
Case
A 13-year-old boy was referred to a neurologist for a 4-month history of generalized fatigue and migraine headaches lasting 3–6 hours that were bilateral and had associated double
vision. Cranial nerve exam was benign and extraocular movements were intact. Magnetic resonance imaging (MRI) was obtained which demonstrated a 1.5 × 0.8 cm left-sided cystic petrous apex lesion that was consistent with cholesterol granuloma (Fig. 1A and B). Specifically, T1-weighted sequences revealed iso- to hyper-intense signal without contrast, and T2-weighted images demonstrated uniform hyperintense signal. Diffusion weighted imaging did not demonstrate restricted diffusion. Temporal bone computed tomography (CT) revealed an expansile lesion with smooth margins, and without erosion of the cochlea or petrous carotid canal (Fig. 1C). The patient was subsequently referred to the authors’ center in 2012 for further evaluation and management. On examination, otomicroscopy revealed mild bilateral retraction of the pars flaccida without debris accumulation and an audiogram showed normal down sloping to mild conductive hearing loss bilaterally. After evaluation, the authors recommended serial imaging and medical therapy for migraine,
☆
Disclosures: Each of the above authors has contributed to, read, and approved the enclosed manuscript. This manuscript is original and it, or any part of it, has not been previously published; nor is it under consideration for publication elsewhere. ★ Institutional Review Board Approval: 131963. ⁎ Corresponding author at: Department of Otolaryngology–Head and Neck Surgery, The Bill Wilkerson Center for Otolaryngology and Communication Sciences, 7209 Medical Center East, South Tower 1215 21st Avenue South, Nashville, TN, 37232-8605, USA. Tel.: +1 615 322 6180; fax: +1 615 343 9556. E-mail addresses: [email protected], [email protected] (G.B. Wanna).
☆☆
http://dx.doi.org/10.1016/j.amjoto.2015.10.013 0196-0709/© 2015 Elsevier Inc. All rights reserved.
Please cite this article as: Yawn RJ, et al, Spontaneous resolution of a petrous apex cholesterol granuloma, Am J Otolaryngol– Head and Neck Med and Surg (2015), http://dx.doi.org/10.1016/j.amjoto.2015.10.013
2
AMER ICA N JOURNAL OF OT OLA RYNGOLOGY–H E A D A N D N E CK M EDI CI N E AN D S U RGE RY X X (2 0 1 5) XXX –XXX
Fig. 1 – (A) Axial post-contrast T1- and (B) axial T2-weighted MRI demonstrating a heterogenous 1.5 × 0.8 cm lesion of the left petrous apex most consistent with cholesterol granuloma (white arrow). (C) Axial computed tomography of the temporal bone demonstrating bony expansion of the left petrous apex (arrow head).
which improved his symptoms. Follow-up imaging at 1.5 years showed no appreciable change in the lesion; however, his most recent MRI at 2.5 years from diagnosis showed complete resolution (Fig. 2).
3.
Discussion
Cholesterol granulomas are benign, expansile, cystic lesions that may develop in many locations, including the mediastinum, orbit, paranasal sinuses, and temporal bone. Histologically, cholesterol granulomas are characterized by chronic inflammation, fibrous tissue reaction, cholesterol crystals, and foreign body giant cells [2]. The histopathogenesis of cholesterol granuloma is controversial and can be potentially explained by either the obstruction-vacuum theory or exposed marrow hypothesis [3]. Classically, MRI demonstrates hyperintense, precontrast T1- and T2-weighted imaging. However, these lesions frequently exhibit heterogenous signal resulting from varying composition. CT generally reveals expansile remodeling of the normal bony architecture of the petrous apex. The radiologic differential diagnosis of petrous apex cholesterol granuloma is wide and includes asymmetric bone marrow deposition or pneumatization, benign
Fig. 2 – (A) Axial T1- and (B) T2-weighted MRI 2.5 years after diagnosis demonstrating resolution of the left petrous apex cholesterol granuloma (white arrow).
effusion, classic epidermoid, “white epidermoid” (epidermoid tumor with high protein content), mucocele, and skull base malignancy (chondrosarcoma versus metastasis). Marrow asymmetry typically shows hyperintense signal on T1weighted imaging that subtracts with fat saturation, and hypointense signal on T2-weighted imaging with no evidence of bony remodeling or expansion on CT. An effusion lacks bony erosion and exhibits hypointense signal on T1-, and hyperintensity on T2-weighted imaging. Epidermoid tumors are non-contrast enhancing, hypointense on T1weighted imaging, hyperintense on T2-weighted imaging, and show restricted diffusion on diffusion-weighted imaging (DWI). Petrous apex mucoceles typically present as hypointense lesions on T1-weighted and hyperintense on T2-weighted imaging that enhance with gadolinium administration. Epidermoid tumors that have central hemorrhage (“white epidermoid”) can show heterogenous intensity or isointensity on T1-weighted imaging thereby appearing similar to cholesterol granuloma on MRI. Chondrosarcoma and other malignancies are commonly hypo- to iso-intense on T1- and hyperintense on T2weighted sequences, with avid contrast uptake. Historically, primary surgical management was routinely employed for cholesterol granulomas of the petrous apex. However, more recent evidence has begun to support an initial observation strategy as many cysts do not grow, and some symptoms at the time of presentation can be difficult to attribute to the cyst [4,5]. Headache, in particular, can be a difficult symptom to address in this patient population given that coexisting headache etiologies, such as migraines, can complicate the presumed symptom profile of a small lesion confined to the petrous apex. In the present case, treating the patient for migraines led to improvement of his symptoms prior to resolution of the cholesterol granuloma. At the authors’ center, we generally recommend primarily managing petrous apex cholesterol granulomas with initial observation and serial imaging, except in the rare cases where decompression may alleviate symptoms clearly attributable to mass effect, such as cranial neuropathy. There is limited understanding of the natural history of these lesions, but many appear to remain quiescent over
Please cite this article as: Yawn RJ, et al, Spontaneous resolution of a petrous apex cholesterol granuloma, Am J Otolaryngol– Head and Neck Med and Surg (2015), http://dx.doi.org/10.1016/j.amjoto.2015.10.013
AMER IC AN JOURNAL OF OT OLA RYNGOLOGY–H E A D A N D NE CK M E D ICI N E AN D S U RGE RY X X (2 0 1 5) XXX –XXX
extended periods of time. Accounting for the spontaneous resolution observed in this index case is currently a matter of speculation. Two theories are that the lesion may have spontaneously drained or the inflammatory process propagating the lesion may have “burned out”. It is also curious that this case involved an adolescent boy, since most cholesterol granulomas are diagnosed after the 4th decade of life. It seems plausible that improvement in Eustachian tube function, involution of the marrow in the petrous apex, or even hormonal events may have also influenced cyst resolution. To the authors’ knowledge, there are no other published reports of spontaneous resolution of a petrous apex cholesterol granuloma. This case adds to the evidence for conservative treatment in patients with small or medium sized lesions and limited symptoms.
3
REFERENCES
[1] Gore MR, Zanation AM, Ebert CS, et al. Cholesterol granuloma of the petrous apex. Otolaryngol Clin North Am 2011;44:1043–58. [2] Hoa M, House JW, Linthicum FH, et al. Petrous apex cholesterol granuloma: pictorial review of radiological considerations in diagnosis and surgical histopathology. J Laryngol Otol 2013; 127:339–48. [3] Jackler RK, Cho M. A new theory to explain the genesis of petrous apex cholesterol granuloma. Otol Neurotol 2003;24:96–106. [4] Castillo MP, Samy RN, Isaacson B, et al. Petrous apex cholesterol granuloma aeration: does it matter? Otolaryngol Head Neck Surg 2008;138:518–22. [5] Mosnier I, Cyna-Gorse F, Grayeli AB, et al. Management of cholesterol granulomas of the petrous apex based on clinical and radiologic evaluation. Otol Neurotol 2002;23:522–8.
Please cite this article as: Yawn RJ, et al, Spontaneous resolution of a petrous apex cholesterol granuloma, Am J Otolaryngol– Head and Neck Med and Surg (2015), http://dx.doi.org/10.1016/j.amjoto.2015.10.013
Available online at www.sciencedirect.com
ScienceDirect www.elsevier.com/locate/amjoto
Spontaneous resolution of a petrous apex cholesterol granuloma☆,☆☆,★ Robert J. Yawn, Alex D. Sweeney, Matthew L. Carlson, George B. Wanna⁎ Department of Otolaryngology–Head and Neck Surgery, Vanderbilt University, Nashville, TN, USA
ARTI CLE I NFO
A BS TRACT
Article history:
Cholesterol granuloma is the most common primary lesion of the petrous apex.
Received 23 October 2015
Management of petrous apex cholesterol granuloma has evolved in recent years from primary surgical treatment to conservative observation. In this article, a case of spontaneous resolution of a petrous apex cholesterol granuloma is described. To the authors’ knowledge, this is the first known report of spontaneous involution of a petrous apex cholesterol granuloma. Radiographic differential diagnosis of petrous apex lesions and the natural history of cholesterol granulomas are discussed. © 2015 Elsevier Inc. All rights reserved.
1.
Introduction
Cholesterol granulomas are the most common primary lesions of the petrous apex, comprising 60% of all pathology arising within this region [1]. A large number of patients are diagnosed incidentally or after obtaining imaging for nonlocalizing headache. Management trends for these lesions have evolved over time, from routine surgery to primary observation with serial imaging. With this trend, natural history data has become increasingly important. Herein we report a case in which spontaneous resolution of a cholesterol granuloma of the petrous apex occurred.
2.
Case
A 13-year-old boy was referred to a neurologist for a 4-month history of generalized fatigue and migraine headaches lasting 3–6 hours that were bilateral and had associated double
vision. Cranial nerve exam was benign and extraocular movements were intact. Magnetic resonance imaging (MRI) was obtained which demonstrated a 1.5 × 0.8 cm left-sided cystic petrous apex lesion that was consistent with cholesterol granuloma (Fig. 1A and B). Specifically, T1-weighted sequences revealed iso- to hyper-intense signal without contrast, and T2-weighted images demonstrated uniform hyperintense signal. Diffusion weighted imaging did not demonstrate restricted diffusion. Temporal bone computed tomography (CT) revealed an expansile lesion with smooth margins, and without erosion of the cochlea or petrous carotid canal (Fig. 1C). The patient was subsequently referred to the authors’ center in 2012 for further evaluation and management. On examination, otomicroscopy revealed mild bilateral retraction of the pars flaccida without debris accumulation and an audiogram showed normal down sloping to mild conductive hearing loss bilaterally. After evaluation, the authors recommended serial imaging and medical therapy for migraine,
☆
Disclosures: Each of the above authors has contributed to, read, and approved the enclosed manuscript. This manuscript is original and it, or any part of it, has not been previously published; nor is it under consideration for publication elsewhere. ★ Institutional Review Board Approval: 131963. ⁎ Corresponding author at: Department of Otolaryngology–Head and Neck Surgery, The Bill Wilkerson Center for Otolaryngology and Communication Sciences, 7209 Medical Center East, South Tower 1215 21st Avenue South, Nashville, TN, 37232-8605, USA. Tel.: +1 615 322 6180; fax: +1 615 343 9556. E-mail addresses: [email protected], [email protected] (G.B. Wanna).
☆☆
http://dx.doi.org/10.1016/j.amjoto.2015.10.013 0196-0709/© 2015 Elsevier Inc. All rights reserved.
Please cite this article as: Yawn RJ, et al, Spontaneous resolution of a petrous apex cholesterol granuloma, Am J Otolaryngol– Head and Neck Med and Surg (2015), http://dx.doi.org/10.1016/j.amjoto.2015.10.013
2
AMER ICA N JOURNAL OF OT OLA RYNGOLOGY–H E A D A N D N E CK M EDI CI N E AN D S U RGE RY X X (2 0 1 5) XXX –XXX
Fig. 1 – (A) Axial post-contrast T1- and (B) axial T2-weighted MRI demonstrating a heterogenous 1.5 × 0.8 cm lesion of the left petrous apex most consistent with cholesterol granuloma (white arrow). (C) Axial computed tomography of the temporal bone demonstrating bony expansion of the left petrous apex (arrow head).
which improved his symptoms. Follow-up imaging at 1.5 years showed no appreciable change in the lesion; however, his most recent MRI at 2.5 years from diagnosis showed complete resolution (Fig. 2).
3.
Discussion
Cholesterol granulomas are benign, expansile, cystic lesions that may develop in many locations, including the mediastinum, orbit, paranasal sinuses, and temporal bone. Histologically, cholesterol granulomas are characterized by chronic inflammation, fibrous tissue reaction, cholesterol crystals, and foreign body giant cells [2]. The histopathogenesis of cholesterol granuloma is controversial and can be potentially explained by either the obstruction-vacuum theory or exposed marrow hypothesis [3]. Classically, MRI demonstrates hyperintense, precontrast T1- and T2-weighted imaging. However, these lesions frequently exhibit heterogenous signal resulting from varying composition. CT generally reveals expansile remodeling of the normal bony architecture of the petrous apex. The radiologic differential diagnosis of petrous apex cholesterol granuloma is wide and includes asymmetric bone marrow deposition or pneumatization, benign
Fig. 2 – (A) Axial T1- and (B) T2-weighted MRI 2.5 years after diagnosis demonstrating resolution of the left petrous apex cholesterol granuloma (white arrow).
effusion, classic epidermoid, “white epidermoid” (epidermoid tumor with high protein content), mucocele, and skull base malignancy (chondrosarcoma versus metastasis). Marrow asymmetry typically shows hyperintense signal on T1weighted imaging that subtracts with fat saturation, and hypointense signal on T2-weighted imaging with no evidence of bony remodeling or expansion on CT. An effusion lacks bony erosion and exhibits hypointense signal on T1-, and hyperintensity on T2-weighted imaging. Epidermoid tumors are non-contrast enhancing, hypointense on T1weighted imaging, hyperintense on T2-weighted imaging, and show restricted diffusion on diffusion-weighted imaging (DWI). Petrous apex mucoceles typically present as hypointense lesions on T1-weighted and hyperintense on T2-weighted imaging that enhance with gadolinium administration. Epidermoid tumors that have central hemorrhage (“white epidermoid”) can show heterogenous intensity or isointensity on T1-weighted imaging thereby appearing similar to cholesterol granuloma on MRI. Chondrosarcoma and other malignancies are commonly hypo- to iso-intense on T1- and hyperintense on T2weighted sequences, with avid contrast uptake. Historically, primary surgical management was routinely employed for cholesterol granulomas of the petrous apex. However, more recent evidence has begun to support an initial observation strategy as many cysts do not grow, and some symptoms at the time of presentation can be difficult to attribute to the cyst [4,5]. Headache, in particular, can be a difficult symptom to address in this patient population given that coexisting headache etiologies, such as migraines, can complicate the presumed symptom profile of a small lesion confined to the petrous apex. In the present case, treating the patient for migraines led to improvement of his symptoms prior to resolution of the cholesterol granuloma. At the authors’ center, we generally recommend primarily managing petrous apex cholesterol granulomas with initial observation and serial imaging, except in the rare cases where decompression may alleviate symptoms clearly attributable to mass effect, such as cranial neuropathy. There is limited understanding of the natural history of these lesions, but many appear to remain quiescent over
Please cite this article as: Yawn RJ, et al, Spontaneous resolution of a petrous apex cholesterol granuloma, Am J Otolaryngol– Head and Neck Med and Surg (2015), http://dx.doi.org/10.1016/j.amjoto.2015.10.013
AMER IC AN JOURNAL OF OT OLA RYNGOLOGY–H E A D A N D NE CK M E D ICI N E AN D S U RGE RY X X (2 0 1 5) XXX –XXX
extended periods of time. Accounting for the spontaneous resolution observed in this index case is currently a matter of speculation. Two theories are that the lesion may have spontaneously drained or the inflammatory process propagating the lesion may have “burned out”. It is also curious that this case involved an adolescent boy, since most cholesterol granulomas are diagnosed after the 4th decade of life. It seems plausible that improvement in Eustachian tube function, involution of the marrow in the petrous apex, or even hormonal events may have also influenced cyst resolution. To the authors’ knowledge, there are no other published reports of spontaneous resolution of a petrous apex cholesterol granuloma. This case adds to the evidence for conservative treatment in patients with small or medium sized lesions and limited symptoms.
3
REFERENCES
[1] Gore MR, Zanation AM, Ebert CS, et al. Cholesterol granuloma of the petrous apex. Otolaryngol Clin North Am 2011;44:1043–58. [2] Hoa M, House JW, Linthicum FH, et al. Petrous apex cholesterol granuloma: pictorial review of radiological considerations in diagnosis and surgical histopathology. J Laryngol Otol 2013; 127:339–48. [3] Jackler RK, Cho M. A new theory to explain the genesis of petrous apex cholesterol granuloma. Otol Neurotol 2003;24:96–106. [4] Castillo MP, Samy RN, Isaacson B, et al. Petrous apex cholesterol granuloma aeration: does it matter? Otolaryngol Head Neck Surg 2008;138:518–22. [5] Mosnier I, Cyna-Gorse F, Grayeli AB, et al. Management of cholesterol granulomas of the petrous apex based on clinical and radiologic evaluation. Otol Neurotol 2002;23:522–8.
Please cite this article as: Yawn RJ, et al, Spontaneous resolution of a petrous apex cholesterol granuloma, Am J Otolaryngol– Head and Neck Med and Surg (2015), http://dx.doi.org/10.1016/j.amjoto.2015.10.013
