170 Extramedullary Hematopoiesis in a Pleural Biopsy: A Case Report

Abstract

Extramedullary hematopoiesis is a rare complication of some hematologic disorders, and lung as a site for this process is even more rare. We present the case of a 54-year-old woman with a known history of primary myelofibrosis who presented with a seven-week history of dyspnea, palpitations, dizziness, and lightheadedness. Chest imaging showed a left-sided pleural effusion, atelectasis, and sclerotic bony structures that were suspicious for malignancy. Pleural biopsy showed maturing erythroid and myeloid cells, small clusters of erythroid and myeloid precursors, dysplastic megakaryocytes, and aggregates of small mature lymphocytes. This case highlights the importance of knowing a patient’s clinical history. In addition, pathologists should be aware of these rare presentations of extramedullary hematopoiesis so as to not overinterpret their clinical significance or confuse them with a neoplastic process.