A Rare Case of Leukemic Involvement in Pleural Effusion

Abstract

INTRODUCTION: Acute Myelogenous Leukemia (AML) is the most common form of acute leukemia in the adult population, accounting for approximately 80% of acute leukemias in adults. The incidence of AML increases with advancing age. In patients younger than 65 years, the incidence is approximately 1.3 per 100000 people, while patients older than 65 years, the incidence is approximately 12.2 per 100000. Hematologic malignancies, such as acute and chronic leukemias, rarely result in pleural effusion during their clinical course. Pulmonary complications of AML are observed in 19%, infection being the most common. Most cases of leukemic pleural effusion reflect disease severity and have been associated with a poor prognosis.CASE PRESENTATION: This is a case of a 36 year-old male with a past medical history of AML with complex cytogenetics (rearrangements 11q, 17q, 17p); treated with Cytarabine and Daunorubicin who came to the emergency room due to general malaise and epigastric pain. Vitals signs remarkable for tachycardia. Physical examination showed decreased breath sounds on left lower lung and dullness to percussion. Laboratories were remarkable for leukopenia, normocytic anemia and normal platelet count. Renal/hepatic function and electrolyte levels were within normal limits. During hospitalization, patient presented with shortness of breath, tachycardia and decreased peripheral saturation. Chest CT Scan was completed and revealed pulmonary infiltrates with miliary pattern and pleural trabecules associated with a moderate left sided pleural effusion. The patient was initiated on Levofloxacin and consulted to Pneumology services for further work up. Bronchoscopy with BAL was performed and was negative for infection. A thoracentesis was completed and consistent with exudative fluid per lights criteria. Cytology revealed large monomorphic population of atypical blastoid cells showing hypochromcatic irregular nuclei, nucleoli and scant cytoplasm. Immunohistochemistry positive for CD3, CD4, CD15, CD 34, CD68 and Myeloperoxidase with a Ki67. These findings are suggestive of granulocytic sarcoma (chloroma).DISCUSSION: Leukemic involvement of the pleura can manifest with pleural effusion, pleural masses or thickening, or a combination of the two. In leukemic patients, common causes of pleural effusion include bacterial or viral infections, or disseminated solid tumors and complication of chemotherapy. Pleural effusions in these patients are more likely to be benign than malignant.CONCLUSIONS: Pleural effusions may be the first presentation of a hematologic malignancy or may develop during the course of the disease. These are a rare occurrence in patients with AML also known as granulocytic sarcoma or pleural chloroma. This demonstrates the importance of the cytopathology specimens obtained in pleural fluid since an early detection of any determined disease could guide effective therapy.