Interdigitating dendritic cell sarcoma presenting in the nasal region.

Interdigitating dendritic cell sarcoma (IDCS) is an extremely rare neoplasm derived from antigen-presenting cells. IDCS displays aggressive behavior in a third of all cases, and the most common involvement is a solitary lymph node. We report the case of an 87-year-old woman with a right nasal mass. She underwent a wide local excision and right functional lymphadenectomy. Histopathological, immunohistochemical and molecular studies were consistent with the diagnosis of IDCS. Although it is extremely rare, this case suggests that extranodal IDCS should be considered in the differential diagnosis of undifferentiated fusiform neoplasms.