Diabetic myonecrosis

Biopsy cultures for bacteria, fungi, acid-fast bacilli and stains are negative in simple myonecrosis.

MRI is the exam of choice and shows increased signal on T2 weighted images within areas of muscle oedema.

Contrast enhancement is helpful but must be weighed against the risk of Nephrogenic Systemic Fibrosis as many diabetics have underlying chronic kidney disease.

Arteriography reveals large and medium vessel arteriosclerosis occasionally with dye within the area of tissue infarction.

[2] A large number of conditions may cause symptoms and signs similar to diabetic myonecrosis and include: deep vein thrombosis, thrombophlebitis, cellulitis, fasciitis, abscess, haematoma, myositis, pseudothrombophlebitis (ruptured synovial cyst), pyomyositis, parasitic myositis, osteomyelitis, calcific myonecrosis, myositis ossificans, diabetic myotrophy, muscle strain or rupture, bursitis, vasculitis, arterial occlusion, haemangioma, lymphoedema, sarcoidosis, tuberculosis, cat-scratch disease, amyloidosis, as well as tumours of lipoma, chondroma, fibroma, leiomyoma, and sarcoma.

Coronal fat suppressed STIR image demonstrating enlargement and increased signal in the left adductor muscle group with associated subcutaneous edema in a patient with diabetic myonecrosis.
Axial fat suppressed T2 weighted MRI image showing hyperintense signal and enlargement of the left thigh adductor muscle group in diabetic myonecrosis.
Axial fat suppressed post gadolinium contrast enhancement MRI image showing absent enhancement in the left thigh adductor muscles centrally indicating necrosis in diabetic myonecrosis.