Isolated mediastinal amyloidosis mimicking a neoplastic lesion.

Isolated mediastinal amyloidosis is a rare condition. We report an unusual case of amyloid presented as an isolated mass, entirely confined within anterior mediastinum and FDG-avid, mimicking a neoplastic lesion. Because the differential diagnosis included several diseases as lymphoma, a biopsy via mediastinotomy was attended to avoid unnecessary sternotomy. The pathological results diagnosed to be an amyloidosis. The patient was asymptomatic and biopsy allowed an exact diagnosis, thus we decided against the complete excision. No monoclonal gammopathy and/or amyloid deposition were found. Thus, other treatments as high-dose melphalan and/or autologous stem cell transplantation were not indicated.