[Follicular dendritic reticulum cell sarcoma in a cervical lymph node].

Follicular dendritic cells (FDC) constitute an essential component of B cell follicles, normally serving as antigen-presenting cells and as cells regulating the germinal center reaction. FDC sarcoma is a very rare tumor. We report the case of a 55-year-old male patient who showed persistent cervical lymph node swelling. On biopsy the tumor consisted of spindle cells with nuclear atypia. Immunophenotypic investigation of the tumor tissue revealed a FDC sarcoma of a cervical lymph node. The tumor cells were characterized immunohistochemically especially by the expression of CD21 and focal expression of CD68. In conclusion, FDC sarcoma has to be considered in cases of tumors of uncertain origin in cervical lymph nodes, tonsils, soft palate, or nasopharynx. For clinical practice, it is important to note that sarcomas in cervical lymph nodes are not necessarily metastases but can be primary tumors.