Soft-tissue amyloidoma of the extremities: a case report and review of literature

Amyloidosis is a heterogeneous group of disorders characterized by extracellular deposition of unique protein fibrils. Amyloidosis may be hereditary or acquired, and the deposits may be focal, localized, or systemic in distribution. The least common presentation of an amyloid deposition is as a discrete mass called amyloidoma or amyloid tumor. Although described at various body sites, soft-tissue amyloidoma in an extremity is exceedingly rare. We report such a case of a large amyloidoma in the thigh, which simulated a soft-tissue sarcoma. In spite of attaining a very large size over a course of more than 20 years, the clinical course and the histology of this lesion were benign. Awareness of this entity will allow this rare diagnosis to be considered, prevent confusion with malignant disease, and allow appropriate management and patient reassurance. A review of literature on soft-tissue amyloidomas of extremities is also being presented. (orig.)