Abstract
Background : We report a case of granulocytic sarcoma accompanying a mediastinal tumor diagnosed based on pleural effusion cytodiagnosis.
Case : A 50-year-old woman admitted for a right breast tumor and dyspnea associated with facial edema had no abnormalities in blood tests or biochemical profile. Computed tomography (CT) showed pleural thickening and effusion, a mediastinal tumor, and a lymph node lesion. Suspecting either malignant lymphoma or malignant mesothelioma, we cytologically diagnosed the pleural effusion. Findings showed individually dispersed round tumor cells, and cytoplasm showed basophilia with some small vacuoles. Tumor cells showed little cytoplasm, mild pleomorphism, and an irregular contour, and contained multiple nucleoli. Cell views suggested malignant lymphoma, but tumor cells were immunohistochemically negative for CD3, CD20, and CD79a. Giemsa staining identified both azurophilic granules and Auer rods in reexamination. The many peroxidase-positive cells yielded a diagnosis of granulocytic sarcoma based on flow cytometry (FCM) and immunohistochemistry findings.
Conclusion : Cases of granulocytic sarcoma are often diagnosed incorrectly as malignant lymphoma, and we recommend immunohistochemistry evaluation to select the most appropriate treatment and thereby improve prognosis.
