Acute monocytic leukemia recurring as bilateral perilimbal infiltrates. Immunohistochemical and ultrastructural confirmation.

A 28-year-old woman developed leukopenia and slight cervical lymphadenopathy. Bone marrow aspiration and special stains established the diagnosis of acute monocytic leukemia. Following chemotherapy a complete hematologic remission was elicited. Seven months later, she consulted an ophthalmologist because of bilateral conjunctival lesions. Ophthalmologic examination showed subconjunctival, perilimbal grayish-pink infiltrates. A conjunctival biopsy disclosed sheets of mononuclear cells consistent with acute monocytic leukemia. Four months later, she developed cutaneous lesions in the face and chest wall. Subsequent biopsies of conjunctiva and skin and immunohistochemical demonstration of muramidase in the tumor cells supported the diagnosis of monocytic leukemia. Electron microscopic studies were particularly valuable and disclosed that more than 80% of the leukemic cells contained two types of cytoplasmic complexes of rough endoplasmic reticulum that displayed both tubular and helical configurations. These complexes differed morphologically from the ribosome-lamellar complexes observed in hairy cell leukemia and other hematologic disorders.