Low grade B cell lymphoma arising in a background of multifocal extra-adrenal myelolipoma

Myelolipomas are rare, benign, non-functioning tumors composed of an admixture of mature adipose tissue and hematopoietic elements. Extra-adrenal myelolipomas are extremely rare, but have been reported in multiple sites including the omentum, presacral, and retroperitoneal areas, along with the thorax, kidneys, liver and stomach. We report a case of a 68-year-old man with low-grade B-cell lymphoma arising in a background of recurrent multifocal extra-adrenal myelolipoma. Pathological evaluation of the lesion and bone marrow showed foci of lymphoid aggregate that were confirmed to be monoclonal B lymphoma by flow cytometry. To our knowledge, this is only the third reported case to feature such a rare combination of diseases. The clinical, radiological, and pathological differential diagnostic findings are discussed.