A Case of Pyomyositis and Primary Thigh Abscess in a Systemic Lupus Erythematous Patient MimickingThigh Hematoma

Routes of extension of infection into the thigh can"nbe either direct, through the subcutaneous tissue, or"nthrough naturally occurring defects in the abdominal"nwall. These include: (1) Along the psoas muscle deep"nto the inguinal ligament; (2) Through the femoral"ncanal; (3) By way of the obturator foramen; and (4)"nThrough the sacrosciatic notch. Pyomyositis is a"nprimary deep bacterial infection of the skeletal muscle"nwithout contiguous spread from adjacent structures,"nusually accompanied by abscess formation within"nthe skeletal muscle, but may also present as a diffuse"ninflammatory or a rapidly progressing myonecrotic"nprocess. Pyomyositis in patients with SLE has rarely"nbeen reported. Because of its rarity and often vague"nclinical presentation, it is unlikely to be considered"nduring the initial differential diagnosis. Moreover,"nthe diagnosis may be delayed as the affected muscle is"ndeeply situated and local signs are not apparent. This"ndelay in diagnosis may result in increased morbidity"nand sometimes a significant mortality rate. Here,"nwe describe a 57-year-old woman, known case of"nSLE with pyomyositis and primary left thigh abscess"nthat mimicked DVT in physical examination and"nhematoma in MRI. The purpose of this report was to"ndraw attention to this rare occurrence and to highlight"nthe etiology, presentation and the imaging features.