Subcutaneous Nasal Schwannoma in a Pediatric Patient: A Rare Case Report with Emphasis on Histopathology's Role in Differential Diagnosis.

BACKGROUND Schwannomas are rare and benign tumors of the nerve sheath, composed of Schwann cells, and they are extremely rare in the nasal area. Here, we report a case that presented to our clinic as a growing nasal mass and was found to be a unilateral subcutaneous schwannoma. There have been a few previous cases reported of such patients having nasal obstruction, epistaxis, or other symptoms, but our patient did not. We stress the importance of considering schwannoma in the differential diagnosis of nasal masses, even in pediatric patients, and the role of histopathology differentiating it from other diagnoses such as neurofibroma. CASE REPORT Our patient was a 9-year-old girl with a painless nasal swelling on the nasal bridge that she first noticed 2 years ago, which started growing gradually and began to become firm. She was otherwise asymptomatic and had no relevant family history. Histopathology revealed an encapsulated spindle cell tumor with both hypo- and hyper-cellular areas, and immunohistochemistry showed that the tumor was strongly positive for S-100 and negative for both desmin and CD34, with blood vessels marking. A final diagnosis of schwannoma was made. CONCLUSIONS We presented a case of nasal septal schwannoma, emphasizing the importance of considering schwannoma in the differential diagnosis of nasal masses, and the role of histopathology to rule out other possible diagnoses.