Interdigitating dendritic cell sarcoma: analysis of two original extra-nodal cases and review of literature.

Interdigitating dendritic cell sarcoma (IDCS) is a rare, highly malignant tumor with a poor prognosis, and current knowledge of this tumor is limited. It is reported that lymph nodes are the primary localization sites. However, in recent years, many primary IDCS have also been reported in the extra-nodal sites, which undoubtedly increases the difficulty of diagnosis. There are very few reports that systematically analyze the clinicopathologic features of IDCS. Here we described two cases of extra-nodal IDCS and reviewed the literature of 44 other published cases of extra-nodal IDCS. Thus, the clinical symptoms, pathological diagnosis, and therapeutic effects of 46 cases of extra-nodal IDCS were summarized in detail. Considering the paucity of available data with regard to IDCS, a thorough and detailed summary would help to better diagnose and treat this neoplasm.