FINE-NEEDLE ASPIRATION CYTOLOGY OF EXTRAMEDULLARY HEMATOPOIESIS (MYELOID METAPLASIA)

Myeloproliferative disease may be associated with extramedullary hemat opoiesis (EH). Clinically, however, the differential diagnosis of soli d masses in these patients includes not only EH but also inflammatory lesions and malignant neoplasms, including granulocytic sarcoma. We re port the fine-needle aspiration (FNA) cytology of extramedullary hemat opoiesis in five patients with a history of myeloproliferative disease . All of the masses developed subsequent to the diagnosis of myeloprol iferative disease. Two of the patients had chronic myelogenous leukemi a, one had essential thrombocythemia, and two had an unspecified chron ic myeloproliferative disorder. The patients ranged in age from 50 to 88 years, and all presented with solid masses involving the kidney (tw o aspirates), liver (one aspirate), and lymph nodes (three aspirates). One of the lymph node aspirates was from a paratracheal lymph node. C ytologically, the lesions were composed of varying numbers of hematopo ietic cells from all three hematologic cell lines. The Diff-Quik stain was especially helpful in the recognition of the hematopoietic cells such as granulocytic precursors, eosinophils, and megakaryocytes. In s everal cases, the megakaryocytic component was particularly prominent. In one case, the Factor VIII immunoperoxidase stain was used to confi rm the megakaryocytic lineage of the multinucleated cells. The cytolog ic differential diagnosis, which includes granulocytic sarcoma, inflam matory disorders, and other lesions containing multinucleated giant ce lls, is discussed. (C) 1993 Wiley-Liss, Inc.