Subscapularis pyomyositis presenting as shoulder stiffness mistaken as frozen shoulder in young female: a case report

Pyomyositis of the shoulder region in young healthy patients is rare but can lead to fatal overwhelming sepsis. Here we present the case of an otherwise healthy 32-year-old female patient with pain and stiffness in the right shoulder. Initial treatment with physical therapy and injection was ineffective. Magnetic resonance imaging of the right shoulder suggested subscapularis intramuscular sarcoma but excision of the muscle and biopsy revealed organized subscapularis pyomyositis. This case demonstrates the importance of investigating predisposing conditions in young patients with painful stiffness mimicking frozen shoulder that does not respond to nonoperative treatment.