Cutaneous cryptococcosis resembling keratoacanthoma

Abstract

Cutaneous cryptococcosis is a manifestation of systemic cryptococcal infection, characterized by polymorphic skin lesions that can make diagnosis challenging. We report an HIV-positive patient with a solitary facial nodule, initially diagnosed as keratoacanthoma. Histopathology, fungal culture, and cerebrospinal fluid analysis confirmed disseminated cryptococcosis with central nervous system involvement caused by Cryptococcus neoformans genotype VNI. He was treated with amphotericin B followed by fluconazole, resulting in complete clinical resolution. This case underscores the need to consider disseminated cryptococcosis in the differential diagnosis of tumorlike skin lesions, particularly in HIV-positive patients.

FIGURE 1:. Clinical presentation, histopathological findings, and long-term outcome in a case of cutaneous cryptococcosis mimicking keratoacanthoma. Clinical presentation: (a) Firm, rounded, skin-colored nodule on the patient’s face, with well-demarcated borders and a central keratinous crust. (b) Postoperative aspects six months after lesion excision and antifungal treatment. (c) No signs of recurrence observed after 10 years of clinical follow-up. Histopathological findings: (d) Hematoxylin and eosin (H&E) stain showing a dense dermal inflammatory infiltrate composed predominantly of lymphocytes, histiocytes, and epithelioid cells (original magnification ×100). (e) Mucicarmine stain highlighting thickened polysaccharide capsules of yeast-like fungal cells (original magnification ×400; scale bar = 10 µm). (f) Grocott-Gomori’s methenamine silver (GMS) stain revealing numerous oval fungal structures with thick, dark-stained cell walls within the dermis (original magnification ×400; scale bar = 10 µm).