Interdigitating dendritic cell tumor.

Interdigitating dendritic cell tumor is an extremely rare neoplasm that mainly occurs in lymph nodes. In this case report, we describe the histopathological and clinical features of a typical interdigitating dendritic cell case in a 30-year-old Saudi female who presented with a painless unilateral left neck mass. Microscopically, the lesional tissue in the affected lymph node showed whorls and fascicles of spindle cells intermingling with small lymphocytes. The neoplastic cells were strongly and diffusely positive for S-100 protein, vimentin and alpha 1-antichemotrypsin and focally for macrophages marker (CD68). The combined morphological features and immunohistochemical results were diagnostic of interdigitating dendritic cell tumor.