Bilateral intramuscular pseudotumor in a bodybuilder.

A 29-year-old bodybuilder presented with a bilateral palpable and painful soft tissue mass in the deltoid region. CT scan showed a bilateral intramuscular mass within the deltoid muscle with intralesional fat (not shown). For further differentiation and exclusion of a fat-containing sarcomatous lesion, MRI of both shoulders was performed. Axial T1-weighted images (WI) of the right shoulder showed a heterogeneous mass lesion containing multiple fatty components (Fig. A, arrows). Axial T1-WI of the left shoulder depicted a mass with a T1-hyperintense fatty component and marked fat-fluid level (Fig. B, arrow). The lesion also demonstrated a fat-fluid level on a sagittal fat suppressed T2-WI (Fig. C, arrow). The presence of a bilateral fat containing soft tissue mass, combined with a history of local steroid injections were highly suggestive of pseudotumoral fat necrosis with surrounding inflammation rather than a fat-containing sarcoma. Because the lesions were painful, surgical removal was done. Pathological examination of the resection specimens showed fragments of necrotic muscle tissue with cystic degeneration, foamy macrophages and granulomatous foreign body inflammation. These findings confirmed the imaging diagnosis. Because both lesions showed no signs of malignancy and the patient was relieved of his complaints, no further follow-up exams were planned.