Case Report: Necrotizing myositis secondary to a pararectal fistula: diagnostic challenges and multidisciplinary...

Necrotizing soft tissue infections (NSTIs) are rare but life-threatening conditions requiring early diagnosis and aggressive multidisciplinary management. Necrotizing myositis (NM) is an uncommon and particularly severe manifestation, often associated with diagnostic delay and poor outcomes.

We report the case of a 57-year-old man presenting with mild pelvic pain radiating to the posterior thigh. Contrast-enhanced computed tomography revealed a presacral abscess with an extrasphincteric fistulous tract extending into the posterior thigh musculature. Surgical exploration confirmed necrotizing fasciitis with myonecrosis caused by Group A Streptococcus. The patient underwent repeated surgical debridement, broad-spectrum antimicrobial therapy, and adjunctive hyperbaric oxygen therapy, resulting in progressive clinical improvement and complete recovery at six-month follow-up.

This case highlights the importance of early imaging, prompt source control, and multidisciplinary management in atypical NSTIs, while illustrating the potential adjunctive role of HBO₂ in selected patients.