Osteoma in the External Auditory Canal: Two Cases of a Rare Tumor

By June 7, 2019

Jeong, Junhui1; Moon, In Seok2; Choi, Hyun Seung1
1 Department of Otorhinolaryngology, National Health Insurance Service Ilsan Hospital, Goyang, Korea;
2 Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Korea.

Osteoma of the external auditory canal (EAC) is a rare benign tumor with an estimated incidence of 0.05%. Osteoma is a slow growing mass and usually induces no symptoms. However, a mass in the EAC that is suspicious for osteoma should be carefully evaluated, because a large osteoma can cause symptoms.

– Patients: We present two cases of this rare tumor; a 23-year-old woman with symptoms of aural fullness in the right ear and a 19-year-old man with mild symptoms of aural fullness in the right ear.
– Interventions: Diagnostic and therapeutic.

– Main Outcome Measures: With microscope assistance, the mass was surgically excised at the level of the peduncle with the patient under local anesthesia. The base of the excised mass was drilled with a diamond burr to remove all osseous lesions.
– Results: Histopathologic findings showed lamellated bone covered with periosteum and squamous epithelium, consistent with osteoma. Eleven months after surgery, the patients were without symptoms and had not experienced any tumor recurrence.
– Conclusions: EAC osteoma is similar to exostosis, and they should be differentiated. Although there have been debates over differentiating the two diseases, they are histopathologically different. EAC osteoma is rare and can be observed without immediate therapy if there are no symptoms. However, excision should be actively considered in symptomatic patients for the following reasons: osteomas can grow, surgical excision is more difficult with larger masses, and EAC cholesteatomas can develop secondary to EAC obstruction.
– Additional Information: None.