Pleural effusion as the initial extramedullary manifestation of Acute Myeloid Leukemia

Leukemias rarely debut by pleural involvement as the first manifestation of the hematologic malignancy. This complication is most commonly seen in solid tumors such as carcinomas of the breast, lung, gastrointestinal tract and lymphomas. We present a case of a 66 year old male who presented with a pleural leukemic infiltration of his undiagnosed Acute Myeloid Leukemia that was not a complication of the disease extension, but the acute presentation of the illness. Progressive shortness of breath for two weeks, cough, clear sputum and weight loss were the initial complaints. Serum dyscrasia suggested a hematologic abnormality. A chest x-ray performed demonstrated a buildup of fluid with layering in the left pleural cavity. Diagnostic thoracentesis suggested an exudative etiology with cytology remarkable for 62% leukemic myeloblast. The diagnosis was confirmed by bone marrow biopsy with expression of the antigens CD 34+ and CD13+, with unfavorable cytogenetic prognosis and a trisomy 21 chromosomal defect. Chemotherapy was initiated, though no remission achieved with induction chemotherapy. Complications and disease progression precludes in the patient's death. Although rare, due to the unusual presentation of the disease, this case clearly demonstrates the importance of biochemical analysis and cytopathology specimens obtained in pleural fluid.