Indolent Acremonium strictum infection in an immunocompetent patient

A 35‐year‐old housewife presented with an 11‐year history of a painless lesion on the right cheek, which had enlarged over the last 2 years. She had no history of travel or trauma. Various topical and systemic antimicrobial and antifungal agents, such as fluconazole, ketoconazole, sulbactam/ampicillin, and mupirocin, had been prescribed, with a probable diagnosis of pyoderma and blastomycosis, without significant benefit. Her medical history was otherwise unremarkable. Dermatologic examination revealed a well‐circumscribed, erythematous, infiltrative, 8 × 10 cm plaque covering the right cheek and a 2 × 3.5 cm vegetative, ulcerated lesion on the chin ( Fig. 1). There were no sinus tracts or grains. 1Erythematous, infiltrative plaque covering the right cheek, and vegetative, ulcerated lesion on the chin The following laboratory test results were within the normal limits: complete blood count, blood biochemistry, urinalysis, immunoglobulins and complement levels, T lymphocyte, CD4 and CD8 cell counts, and response to mitogens. X‐Rays of the chest and maxillar and mandibular bones were normal. Routine bacterial cultures were negative. Skin biopsies and fungal and mycobacterial cultures were taken with a preliminary diagnosis of deep fungal or mycobacterial infection. Dermatopathologic examination revealed irregular epidermal hyperplasia with follicular plugging. A dense nodular lymphohistiocytic infiltrate was observed within the reticular dermis, with many multinucleated giant cells and plasma cells. In higher magnification, even in hematoxylin and eosin sections, large septate hyphae and spores were noticeable. Periodic acid–Schiff stain revealed abundant fungal structures within the giant cells and extracellularly throughout the inflammatory infiltrate ( Fig. 2). Lymphocytes were rather sparse in comparison to the large amount of microorganisms within the tissue. 2Periodic acid–Schiff‐positive hyphae with phialides and yeast‐like phialoconidia (arrow) within the tissue (× 400) Fungal cultures were performed on Sabouraud's dextrose agar and, within 1 week of incubation, white fungal colonies were observed. On multiple passages at 26 °C, white tufted colonies with a salmon‐colored base had formed ( Fig. 3). Native preparations from the cultured colonies revealed septate hyphae, and 90° angled branches, together with phialides decorated with ellipsoidal conidia with rounded edges ( Fig. 4). These findings were consistent with Acremonium strictum, a saprophytic fungus. 3Fungal culture: salmon‐colored base of the colonies4Lactophenol cotton blue (× 40): 90° branching septate hyphae with ellipsoidal, round‐ended conidia Further laboratory examinations revealed no systemic involvement. Following the diagnosis of Acremonium infection, amphotericin B therapy and surgical excision of the tumoral lesion were planned, but the patient refused further treatment and failed to respond to our follow‐up attempts.