Mucor irregularis infection and lethal midline granuloma: a case report and review of published literature.

Mucor irregularis (Rhizomucor variabilis) infection and lethal midline granuloma (LMG) are characterized by progressive swelling, ulceration, and destruction of the central face that is usually fatal. Pathological features are inflammation, necrosis, and granulation. LMG has been called by various names, and in recent years, it has been known as NK/T cell lymphoma. However, diagnosis still relies on the progressive necrosis course rather than malignancy in histology. The disease has long challenged physicians, particularly when it worsens with radiotherapy or chemotherapy but sometimes achieves total remission without anti-malignancy therapies. We describe a 35-year-old man who had typical clinical-pathological symptoms of LMG, which turned out to be primary M. irregularis infection; that was diagnosed by positive tissue culture and fungal elements in histology. The patient was successfully treated with antifungal therapy (liposomal amphotericin B, total 4,600 mg and amphotericin B total 277 mg, over a duration of 70 days). We hereby review current knowledge about the epidemiology, clinical manifestations, radiographic characteristics, and pathologic features of LMG with those of M. irregularis infection and their associations. We conclude that primary M. irregulars infection can mimic the clinico-pathological symptoms of LMG and the condition responds favorably to aggressive antifungal therapy.