Ochroconis humicola coexisting with esthesioneuroblastoma: an incidental coloniser or allergen?

Ochroconis humicola, a fish pathogen, is rarely reported to cause disease in human. We report its first isolation from nasal tissue of a human immunodeficiency virus-positive young female patient. Histopathologically, the nasal mass was diagnosed as esthesioneuroblastoma. She presented with right-sided nasal obstruction and bleeding for two and half months. Computed tomography scan showed the nasal mass filling the whole right nasal cavity, maxillary, ethmoid and sphenoid sinuses. The direct microscopy of the nasal tissue and mucin demonstrated the presence of septate hyphae. On culture, O. humicola was isolated from the same tissue and the fungus was identified by morphologic, physiologic and molecular data including sequencing of ITS and 28S rDNA regions. No antifungal was prescribed, and the whole mass was resected out by endoscopic surgery. The patient was treated further by radical radiotherapy. After 1 year of follow-up, patient is stable with no recurrence of tumour. The role of this fungus was not clear, as it may be bystander or producing allergic fungal rhinosinusitis.