Primary extranodal lymphoma of skeletal muscles: a report of four cases.

Approximately one-fourth of non-Hodgkin's lymphomas originate in extranodal sites. True primary involvement of soft tissues is quite uncommon and only a few well-documented cases are reported in the literature. We report four cases of primary skeletal muscle lymphoma. Three of the four cases presented with a diffuse large B-cell lymphoma. The clinical history of two cases confirmed that soft tissue masses should be promptly biopsied, since the differential diagnosis comprises benign lesions, as well as sarcoma, primary or metastatic carcinoma, melanoma and lymphoma. As lymphomas have to be treated primarily according to the tumour histology and disease extent, treatment of primary skeletal muscle lymphomas must be planned with these factors in mind. For patients presenting with diffuse large cell histology, a CHOP-like regimen alone or a combined modality with radiotherapy seem to be proper approaches.