Interdigitating dendritic cell sarcoma (IDCS) is an aggressive
neoplasm of which fewer than 25 cases have been reported in the world literature. This
malignancy is difficult to diagnose because of its rarity, and because of the subtle histopathologic features that distinguish IDCS from similar
tumors arising from reticular cells. To date, there exists no consensus on a standard chemotherapeutic regimen for IDCS. Patients with this
malignancy have been treated with
chemotherapy regimens used against non-Hodgkin's
lymphomas. Responses to these regimens have been variable, but mostly unsuccessful. In this article we describe a case of IDCS occurring in a 44 year old female who presented with
abdominal pain and inguinal
adenopathy. Staging of the
tumor with CT scan, PET scan, and bone marrow biopsy demonstrated inguinal and abdominal
lymphadenopathies, a large mass encasing the small bowel, and extensive liver infiltration. Morphologic and cytochemical analysis of biopsies from the abdominal mass and inguinal node were consistent with a diagnosis of IDCS, and immunohistochemical stains of the lymph node were positive for CLA, Kp-1, S-100, while negative for CD1a, CD3, CD20, CKER, and HMB45. Treatment of this patient with ABVD
chemotherapy resulted in rapid clinical improvement with a marked decrease in
tumor burden after two cycles of ABVD, and a complete response after six cycles of
therapy.