INDETERMINATE CELL HISTIOCYTOSIS - A RARE HISTIOCYTIC DISORDER

A 64-year-old woman, otherwise healthy, presented with multiple reddis h-brown, slightly yellowish papules on the face and neck, which had de veloped 3 years earlier. The lesions were painless and nonpruritic and varied in diameter from 1 to 5 mm. Histological and immunohistochemic al examination of cutaneous biopsies revealed a diffuse dermal infiltr ate composed mainly of histiocytes which expressed both Langerhans cel l as well as monocytic/macrophages cell marker characteristics. Electr on microscopic studies revealed no Birbeck granules within the cylopla sm of the neoplastic cells. leading to a diagnosis of indeterminate ce ll histiocytosis. Indeterminate cell histiocytosis is a very rare dise ase characterized by the proliferation of indeterminate histiocytes wh ich morphologically and immunophenotypically resemble Langerhans cells but lack Birbeck granules.