Interdigitating dendritic cell sarcoma involving head and neck region- a report of four cases with review of literature

Interdigitating dendritic cell sarcomas (IDCS) are very rare and aggressive neoplasms that arise from antigen presenting cells. It usually involves lymph nodes, but extra nodal sites are also involved including head & neck region. We report four cases of IDCS involving head & neck region. There were two males and two female patients. Age range was 27 – 75 years. Three cases were extra nodal in location such as mandible, nasoethmoidal region and tonsils. Other case involved right cervical lymph nodes. There were varied histomorphological patterns ranging from spindled to epithelioid appearance, with one case resembling Inflammatory myofibroblastic tumor. All the cases were variably positive for S100, CD68 & LCA. Ki67 index ranged from 10 to 30%. All patients underwent resection with two of them received adjuvant chemotherapy and the other two patients received adjuvant radiotherapy. Two patients had no evidence of disease as on 3 years follow-up. One patient succumbed to the disease in few weeks. One patient was lost to follow-up. Although the incidence of IDCS is extremely rare, this case series highlights the fact that these neoplasms should be considered as differentials in unusual looking tumours.