Fine-needle aspiration of a presacral myelolipoma: a case presentation with flow cytometry and immunohistochemical studies.

Myelolipomas are benign soft-tissue tumors predominantly found in the adrenal gland. Extra-adrenal myelolipomas are rare, with about 30 previous cases reported. Approximately half of the reported cases were located in the presacral region. These were usually found at autopsy or during the workup of vague abdominal symptoms. Histologically, these lesions show bone marrow elements, with adipose tissue and scattered lymphoid aggregates. Radiologically-guided fine-needle aspiration (FNA) is helpful in establishing the diagnosis, thus obviating resection in some patients. We report on a case of an incidental presacral myelolipoma that underwent examination by computer tomography, magnetic resonance imaging, FNA, and immunohistochemical staining. This lesion was also analyzed by flow cytometry. To our knowledge, the use of the latter technique in the characterization of such tumors has not been previously reported.