Skull base osteomyelitis (Necrotising otitis externa) following temporal bone resection and flap reconstruction.

Necrotising otitis externa (NOE) is a life-threatening infection of the external auditory canal with skull base involvement. We report a case of Citrobacter koseri skull base osteomyelitis with NOE-like features, presenting three months following skull base surgery. A 69-year-old man underwent a left lateral temporal bone resection and pinnectomy with thoracodorsal artery perforator flap reconstruction for extensive basal cell carcinoma. Interval computed tomography and magnetic resonance imaging demonstrated enhancement deep to the flap with skull base and nasopharyngeal involvement, raising concern for recurrence. A postnasal space biopsy excluded malignancy, but cultures isolated C. koseri. Following multidisciplinary review, NOE was diagnosed, and oral cotrimoxazole was initiated, with clinical and radiological improvement. This case highlights the challenges in diagnosing postoperative infection after complex skull-base reconstruction.