A Case of Malignant Small Round Cell Tumor of Temporal Bone with Facial Paralysis
A 5-year old boy visited outpatient clinics for left idiopathic acute facial paralysis (House-Brackmann grade IV). Pure tone audiometry showed normal healing level. Oral steroid medication was prescribed for 10 days as scheduled during admission. On imaging study, temporal magnetic resonance imaging showed a partial fluid signal at the left mastoid air cells and abnormal enhancement at the left facial nerve around the genu area (). He was diagnosed with Bell's palsy. However there was no improvement until a month after discharge. His parents wanted to transfer to another hospital and returned six months later. He showed marked improvement without any treatment and there were no sequelae (House-Brackmann grade I). Three months later, he visited again for left intractable otalgia without facial palsy. He had a medication history of local clinics for the last month. On physical examination, the left tympanic membrane could not be observed due to severe narrowing of left external auditory canal (). Pure tone audiometry showed sensorineuronal hearing loss of 60 dB threshold. Temporal bone computed tomography revealed expansile soft tissue densities and diffuse erosive destruction on left temporal bone (). On the basis of these findings, we suggested aggressive infectious disease or destructive cholesteatoma.\nWe performed an emergency modified radical mastoidectomy under general anesthesia. During the operation, we found a pale, grayish tumor occupying the mastoid and middle ear cavity (). On frozen biopsy, it was suspected to be a MSRCT.\nPathologic examination of the resected tumor showed an infiltrating tumor consisting of small round cells (). The results of immunohistochemical stainings for vimentin, neuron specific enolase (NSE), S-100 protein, pancytokeratin, synaptophysin, chromogranin A, smooth muscle actin, Sarcomeric actin, glial fibrillary acidic protein (GFAP), leuko-cyte common antigen were all negative, so we couldn't categorize the tumor.\nAfter the pathologic confirmation, the patient transferred to hematooncologic department for chemotherapy and radiotherapy.