Histiocytic sarcoma of the eyelid.

Histiocytic Sarcoma is a rare malignant hematopoietic neoplasm that can present in extranodal sites including lymph nodes, skin, gastrointestinal tract, and the central nervous system. Only 10% of cases manifest as skin lesions and very few are reported in the head and neck. The authors report a case of histiocytic sarcoma of the eyelid in a 72-year-old male that was clinically diagnosed as a chalazion.