Primary Skeletal Muscle Lymphoma: A Case Report and Literature Review

BackgroundLymphomatous involvement of the muscle is a rarely seen disorder, constituting 0.1-1.4% of all extranodal lymphomas. It maybe seen as the intramuscular involvement of disseminated disease, as an extension from adjacent bone or lymph nodes, or asprimary extranodal lymphoma. Primary lymphoma of the skeletal muscle mainly consists of B-cell non-Hodgkin lymphoma(NHL) (>95%).Case PresentationA 50-year-old male patient presented with progressive swelling and pain in his right flank area over a period of one year. Ultrasound(US) was done, and it showed diffuse enlargement of pelvic and limb muscles with hypoechoic regions that irregularlyinfiltrated normal muscle tissue. An incisional biopsy was done, and the histopathologic diagnosis was diffuse large B-cell lymphoma(DLBCL).ConclusionPrimary intramuscular lymphoma is extremely rare. Nevertheless, it should be considered a differential diagnosis in patientspresenting with intramuscular tumors.