Indeterminate cell histiocytosis (ICH) is a very rare histiocytic disease. We reported a case of generalized ICH presenting as eroded papules and crusts, accompanied with intermittent fever, pulmonary disorder, lymphadenectasis in the mediastinum, and the retroperitoneum. The histopathology indicated a neoplasm that was composed of small nests of large cells with ample pale cytoplasm. Immunohistochemistry results and the absence of Birbeck granules led us to the diagnosis of ICH. Four months later, the patient died of anemia, ascites, and swelling of the limbs.