P303 An unusual case of isolated gluteal abscess

Abstract Poster session 2, September 22, 2022, 12:30 PM - 1:30 PM Background Mucormycosis is an invasive infection caused by fungi belonging to the order Mucorales. The angioinvasive disease caused by these fungi can prove to be fatal despite appropriate treatment. We report an unusual case of a gluteal abscess caused by a probable mucormycosis in an apparently immunocompetent individual. Case Description A 68-year-old gentleman hailing from a rural area of Bihar, India presented with a painful swelling over the left buttock region for 4 weeks. He was a known hypertensive and had ischemic heart disease. He denied any history of fever. The lump had gradually increased in size. He was a retired school teacher with a farmland and reared livestock at home. He was a non-vegetarian and denied any addictions. He had a history of intermittent lower backache for which he used to take occasional intramuscular analgesic injections over his buttocks from a local medical practitioner. On examination, the swelling was about 4 cm X 4 cm in size, fluctuant, with ill-defined margins over the lateral region of the left buttock. The swelling was tender, warm, and not fixed to underlying structures. Systemic examination was unremarkable. Ultrasound examination revealed an ∼7.2 × 4.2 × 7.8 cm cystic lesion with a volume of 126cC. It was located predominantly in subcutaneous fat extending into muscular plane with septa and solid components in the left gluteal region (Fig. 1). It had thick walls and fine internal echoes within. Other investigations were unremarkable except for glycosylated Hb, which was 6.2%. Incision and drainage were done. During the procedure, it was seen as a cyst with a thick wall that was removed in toto. The contents were explored after removal and were found to be yellowish black with mucoid consistency. Histopathological examination revealed numerous broad, ribbon-like, aseptate fungal hyphae with right-angled branching infiltrating the inflamed tissue (Fig.2). There were numerous epithelioid granulomas surrounding the fungal elements in the soft tissue of the wall. The findings were consistent with a fungal abscess caused by mucormycosis. Culture of the fluid/pus was negative. Thus, a diagnosis of mucormycotic gluteal abscess was made and patient was commenced on 50 mg of amphotericin B deoxycholate in view of financial restraints. High resolution computed tomography of chest was done which was unremarkable. He developed an acute kidney injury after 2 doses of amphotericin B deoxycholate which was then stopped. Oral posaconazole was started. He has developed bilateral leg swelling post-oral posaconazole and is commenced on oral spironolactone for the same. The postoperative wound has healed well and there is no new swelling or tenderness over the area. He is planned for further follow-up. Conclusions Isolated gluteal abscess caused by mucormycosis is rare in an apparently immunocompetent host. We assume that repeated intramuscular injections might have caused traumatic inoculation of fungus into the host which led to this outcome.