Cutaneous mucormycosis caused by Mucor irregularis: a case report

Abstract

A 39-year-old female patient presented with a painful plaque with ulcers on the right cheek for 2 months. She had acute myeloid leukemia for 1 year. After treatment, the patient achieved remission, but experienced recurrence half a year prior to the presentation. Skin examination showed a violaceous plaque measuring 5 cm × 5 cm in size on the right cheek with erosions and ulcers in the center, whose surface was covered with yellowish brown crusts. Granulation tissues were observed on the plaque, and yellow pus was exuded after the crusts were removed. The boundary of the plaque was sharp and slightly elevated, and there was obvious tenderness on palpation. Laboratory examination revealed increased white blood cell (WBC, 28.75 × 109/L) and lymphocyte counts (27.17 × 109/L) , but decreased neutrophil (1.05 × 109/L) and red blood cell counts (2.20 × 1012/L) , hemoglobin level (69 g/L) and platelet count (84 × 109/L) in the peripheral blood. The hepatic and renal function, electrolyte level and electrocardiogram were normal. Hematoxylin and eosin (HE) staining and periodic acid-Schiff staining of the lesion showed a large number of lymphocytes and histiocytes infiltrating in the dermis and broad aseptate hyphae. The fungal microculture yielded broad hyalinea septate hyphae, fungal rhizoids, stolons and spherical sporangia. The isolated fungus was identified as Mucor irregularis by using molecular biology techniques. The patient was diagnosed with primary cutaneous mucormycosis caused by Mucor irregularis complicated by acute myeloid leukemia. Then, the patient was treated with oral hydroxyurea at a dose of 0.5 g thrice a day, a single-dose intravenous infusion of 4 units of red blood cell suspension, and intravenous drip infusion of amphotericin B at an initial dose of 5 mg/d, which increased by 5 mg every day until 25 mg/d (about 0.5 mg·kg-1·d-1) . After the treatment, the lesion gradually became flat and smaller. After 12-day treatment, the patient was discharged because of a certain reason, and finally lost to follow-up. Key words: Mucormycosis; Leukemia, myeloid; Amphotericin B; Mucorirregularis