A rare case report of mixed olfactory neuroblastoma: Carcinoma with review of literature.

Background: Olfactory neuroblastoma (ONB) is a rare malignant neuroectodermal tumor of the nasal cavity. Mixed olfactory neuroblastoma which contains areas of divergent differentiation is even rare. Till date, only 4 cases of mixed olfactory neuroblastomas have been reported.

Case Description: We report the case of a 46-year-old male who presented with the chief complaints of nasal bleeding and nasal obstruction since 4 months. Radiological imaging was suggestive of a large heterogeneous mass in the left superior nasal cavity with extensions into bilateral maxillary, ethmoidal, and sphenoidal sinuses, as well as into the anterior cranial fossa. Bifrontal osteoplastic craniotomy and excision of the intracranial part of the tumor from above and transnasal endoscopic removal of the mass in the nasal cavities and paranasal sinuses from below was done. Postoperative radiological imaging was suggestive of gross complete excision of the mass. Histopathological diagnosis was "mixed olfactory neuroblastoma-carcinoma (squamous and glandular differentiation) Hyams grade IV." On immunohistochemistry, the tumor cells were positive for neuron specific enolase (NSE), synaptophysin, chromogranin, and CD56 and peripherally for S100. Because of personal reasons, the patient did not take adjuvant radiotherapy. He presented again after 2 months with a full blown recurrence of esthesioneuroblastoma with similar extensions as before. The patient is now planned for salvage surgery followed by adjuvant chemoradiation.

Conclusion: We report the 5 case in the world of mixed olfactory neuroblastoma-carcinoma with squamous and glandular differentiation. From an analysis of the findings in the 5 reported cases of mixed olfactory neuroblastomas, one might infer that a separate subcategory of ONB, i.e., mixed ONB, should be considered because mixed ONBs have an aggressive behavior, high rates of recurrence, and these tumors should be treated aggressively by multimodality treatment.