A Rare Case of Cytokeratin-Positive Interstitial Reticulum Cell Sarcoma and Review of the Entity.

The tumors of dendritic/reticulum cells constitutes the rarest tumors affecting the lymphoid tissues. Among them tumors derived from fibroblastic reticular cells (FBRCs) are very rare, and those of cytokeratin (CK)-positive interstitial reticulum cells (CIRCs) origin are even more rare. These tumors can be easily misdiagnosed as tumors of other dendritic cells, myofibroblastic tumors or even metastatic poorly differentiated carcinomas. Less than twenty such cases have been reported in the literature till date. We present such a rare case of CIRC sarcoma in cervical lymph node of a 64-year-old man.