[Interdigitating dendritic cell sarcoma/tumor: a clinicopathologic study].

OBJECTIVE: To study the clinicopathologic characteristics and diagnostic criteria of interdigitating dendritic cell sarcoma/tumor (IDCS/T).

METHODS: The clinical features, histologic findings and results of immunohistochemical study in six cases of IDCS/T were analyzed, with review of literature.

RESULTS: The age of patients ranged from 20 to 68 years. The sites of involvement included lymph node, tonsil and soft tissue. Histologically, the tumor cells were arranged in sheets, fascicles or whorls and intimately admixed with abundant lymphocytes and plasma cells. They were oval to spindly in shape and contained pale eosinophilic cytoplasm, oval nuclei and distinct nucleoli.Immunohistochemical study showed that the tumor cells were positive for S-100 protein and CD68.

CONCLUSIONS: IDCS/T is a rare malignant tumor with poor prognosis. It carries distinctive histologic pattern and immunophenotype. The entity needs to be distinguished from follicular dendritic cell sarcoma/tumor, anaplastic large cell lymphoma and other spindle cell sarcomas in occurring soft tissue.