Muscle lymphoma

Muscle lymphoma is a rare manifestation of lymphoma.

Epidemiology

Muscle lymphoma is rare, representing <2% of all lymphomas. The average age of presentation is 70 years .

Clinical presentation

Focal swelling and/or pain along with B-type symptoms . Any muscle can be involved but most commonly :

• thigh
• trunk
• upper limb
• leg

Pathology

Muscle lymphoma is typically the non-Hodgkin type. It can manifest in two ways :

• metastatic spread from primary disease (e.g. nodal, osseous)
• primary lesion (i.e. primary muscle lymphoma), which is less common

Risk factors

• HIV/AIDS 

Radiographic features

MRI

Muscle enlargement with focal mass or diffuse abnormal signal :

• T1: iso- or hyperintense to normal muscle
• T2: intermediate signal intensity to fat and muscle
• Gad (C+): diffuse (more common), thick peripheral and/or septal marginal enhancement

Differential diagnosis

Other soft tissue tumors should be considered :

• metastatic carcinoma
• rhabdomyosarcoma
• extraskeletal Ewing sarcoma

Infection (pyomyositis) should also be considered.