Hemangiopericytoma Presenting as an External Auditory Canal Mass

A 35-year-old man presented with a history of progressive, pulsatile, left-sided tinnitus, deafness, headache, and postauricular swelling. Otoscopic examination of the left side revealed a pinkish, glistening, smooth mass with prominent vascular markings on the surface, originating from the posterosuperior part of the canal and occluding the posteroinferior external auditory canal. Only the anterorosuperior quadrant of the tympanic membrane could be visualized (figure 1). Based on the clinical features, which were mainly otologic, a diagnosis of a glomus tumor was made.

Figure 1.

Otoscopic View of the Left Ear Shows a Pinkish Mass in the External Auditory Canal.

Pure-tone audiometry revealed moderate mixed hearing loss on the left side and normal hearing on the right side. Computed tomography showed a large, hyperdense dura-based mass along the left temporal bone invading the mastoid antrum, with destruction of the tegmen tympani. Magnetic resonance imaging revealed a large, well-circumscribed, lobulated mass with multiple vascular flow voids at the center (sunray/spoke-wheel pattern). Radiologically, the diagnosis was suggestive of a petromastoid meningioma.

The patient underwent left suboccipital craniotomy and total resection of the tumor. To our surprise, histopathologic examination of the specimen revealed a diagnosis of hemangiopericytoma. The patient made a good postoperative recovery and underwent radiotherapy to prevent local recurrence. He was asymptomatic and had a normal otoscopic examination at the 10-month follow-up (figure 2).

Figure 2.

The Patient's Otoscopic Examination is Normal at the 10-Month Follow-Up.

Hemangiopericytoma is an uncommon hypervascular mesenchymal neoplasm originating from modified contractile smooth-muscle cells that surround capillaries and postcapillary venules, called pericytes of Zimmerman. Stout and Murray first described hemangiopericytoma as a specific entity in 1942. ¹ It represents less than 2 to 5% of soft-tissue sarcomas and approximately 1% of all vascular tumors. ² Hemangiopericytomas are ubiquitous tumors; they have an almost equal sex distribution and occur at all ages, but with a predilection for middle age. ³ Approximately 13 to 25% of hemangiopericytomas originate in the head and neck region. ⁴ In order of descending frequency, the principal extracranial locations include the orbit, tongue, nasopharynx, nose, paranasal sinuses, mandible, and pharynx. Intracranial hemangiopericytomas represent only 0.29% of all intracranial neoplasms. ⁵

Adequate surgical resection with negative margins appears to be the most appropriate therapy for hemangiopericytoma. Radiotherapy is a necessary complement to surgery to prevent or control local recurrence, and it may be helpful in the therapeutic management of tumors involving vital or delicate anatomic structures, in which dissection becomes risky or impossible.

Although hemangiopericytomas of the temporal bone are uncommon, they should be considered in the differential diagnosis for all hypervascular lesions of the temporal bone.