Soft-tissue hemangioblastoma of the retroperitoneum: a case study and review of the literature.

A 71-year-old woman was found to have a solid retroperitoneal mass measuring 7 x 6 cm on a computed tomography scan. The tumor was not connected to the spinal cord or large nerves. It was resected and showed the typical histology of hemangioblastoma, that is, numerous capillaries and stromal cells with focal cytoplasmic vacuolization. Immunohistochemical study revealed that the tumor stromal cells were positive for S-100 protein, neuron-specific enolase, and inhibin-α, supporting the diagnosis. In addition, the tumor cells labeled for carbonic anhydrase IX and brachyury. The diffuse strong carbonic anhydrase IX expression suggested that soft-tissue hemangioblastoma may share with central nervous system hemangioblastoma the tumorigenic mechanism involving the von Hippel-Lindau gene product and hypoxia-inducible factor. The brachyury expression observed in this case, albeit focal and weak, may implicate embryonic hemangioblasts as a potential line of differentiation, as was proposed in central nervous system hemangioblastoma. The patient is well 4 years after the surgery without any recurrence. A review of the literature revealed that soft-tissue hemangioblastoma is typically a solid tumor found in older females and often involves the retroperitoneum/pelvis.