Interdigitating reticulum cell sarcoma with unusual features.

A case of interdigitating reticulum cell sarcoma is reported in a cervical lymph node of a 67-year-old man who had a previously diagnosed nodular lymphocytic lymphoma in the same anatomic location. Ultrastructurally, the neoplastic cells contained cylindrical confronting cisternae, and associated benign lymphocytes had tubuloreticular structures in their cytoplasm. The patient was treated with combination chemotherapy-radiation therapy and is alive and well with no evidence of disease approximately 2 years after completing therapy. The clinical and pathologic features of previously reported cases of interdigitating reticulum cell sarcomas are compared to those of the reported case.