Soft-tissue amyloidoma

Localized plantar amyloidosis: case report and review of the literature

Amyloidosis may be hereditary or acquired and the deposits can be focal, localized, or systemic in distribution. A discrete mass of amyloid deposition is called an amyloidoma and is the least common presentation. Soft tissue amyloidoma in an extremity is exceedingly rare. Amyloidomas can mimic malignant neoplasms both clinically and radiologically. We report a case of an amyloidoma in the foot, which has not been previously described. Clinical history, pathology, and immunohistochemistry and appearance by MRI are described. Knowledge of this atypical lesion, in its various forms, is important for experts in musculoskeletal radiology, pathology, surgery, and oncology to appreciate as it can prevent confusion with more sinister disease processes such as malignancy. Early recognition can help guide appropriate management in a timely fashion.

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

Amyloidoma (tumoral amyloidosis) is defined as a solitary localized tumorlike deposit of amyloid, in the absence of systemic amyloidosis. Amyloidoma is the least common presentation of tissue amyloid deposition and may be of AL-type or AA-type. It has been reported in many anatomic sites including the respiratory, genitourinary, and gastrointestinal tracts, as well as internal viscera, the central nervous system, skin, breast, and soft tissues. Amyloidoma of soft tissues is extremely rare and occurs mainly in the mediastinum and abdomen. Soft tissue amyloidoma of the extremities is even more uncommon and, when strictly defined, only 11 such cases are reported in the English language to date. Most have been of AA-type and have occurred on the leg. Some have been associated with local trauma, surgery, infection, or peripheral vascular disease, and a few patients have been diabetic. We report the case of a soft tissue amyloidoma on the leg of an 85-year-old woman. Clinically, it was a subcutaneous nodule on the left shin, of approximately 4 years duration. Traumatic fat necrosis was suspected. On excision a firm gray/tan, lobulated, soft tissue mass, measuring 2.3 cm in greatest dimension, was observed. At the microscopic level, it was seen to consist mainly of amyloid, associated with a giant cell granulomatous reaction, a patchy lymphocytic infiltrate, and focal microcalcification. The features were those of a soft tissue amyloidoma of the extremity. Persistence of congophilia after pretreatment with permanganate in this case suggested the presence of AL amyloid.

Soft Tissue Amyloidoma of the Extremities: A Case Report and Review of the Literature

The deposition of amyloid as a distinct, clinically apparent mass is uncommon, particularly in soft tissues. Among reported sites of soft tissue amyloidomas, the extremities are quite rare. Amyloid tumors can mimic malignant neoplasms both clinically and radiologically. We report a case of AA amyloidoma presenting in the deltoid region with radiological features suggesting sarcoma. Cytomorphology from fine-needle aspiration material, tissue histology, and appearance by magnetic resonance imaging are described. The literature on soft tissue amyloidoma is reviewed.

Recurrent Amyloidoma of Soft Tissue With Exuberant Giant Cell Reaction

Amyloidoma (localized tumorlike amyloidosis) in the soft tissues is rare. We present an instructive case of recurrent amyloidoma in the soft tissue of the ankle in a 45-year-old man with multiple surgical procedures and chronic osteomyelitis of the underlying bones. The lesion evaded diagnosis because of a florid giant cell reaction that led to various misdiagnoses, including giant cell tumor of tendon sheath, foreign body reaction secondary to surgery, and pseudogout. This case demonstrates the importance of considering the possibility of amyloidoma when a giant cell–rich lesion is encountered in the soft tissues.

Soft tissue amyloidoma with features of plasmacytoma: a case report and review

Soft tissue amyloidoma is rare, and soft tissue amyloidoma associated with plasmacytoma and without evidence of systemic amyloidosis is even more rare. We report a case of soft tissue amyloidoma associated with an apparently localized monoclonal proliferation of plasma cells (plasmacytoma).