Emphysematous osteomyelitis due to Escherichia coli in multiple myeloma.

A 74-year-old woman with multiple myeloma (MM) presented with fever and diffuse abdominal pain. She had received 2 cycles of chemotherapy with thalidomide-cyclophosphamide-dexamethasone for relapsed MM after previous chemotherapy with bortezomib-melphalan-prednisolone and lenalidomide-dexamethasone.

She developed septic shock, and Escherichia coli was observed in her blood culture. She gradually improved with antibiotics (meropenem). Chest computed tomography (CT) showed incidental intraosseous gas in her sternum ( A ) and T6 vertebra ( B ), which was absent on CT images taken 3 months prior. Following the diagnosis of emphysematous osteomyelitis due to E. coli , antibiotics and supportive care were continued. The patient recovered and was discharged 20 days later.

Intraosseous gas is a sign of emphysematous osteomyelitis caused by gas-forming organisms. Important differential diagnoses include degenerative diseases, trauma (including iatrogenic), or less commonly, neoplasm. However, when a patient with MM presents with bone lesions and concomitant intraosseous gas, the lesion could be misinterpreted as a destructive manifestation of MM without suspicion of infection.

These CT findings call attention to various bony manifestations of MM. Our findings also raise concern about osteomyelitis and/or emphysematous osteomyelitis, especially in a patient with confirmed bacteremia and bony manifestations.