A 70-Year-Old Kidney Transplant Recipient Presenting With Persistent Leg Cellulitis

Diagnosis: Disseminated cryptococcosis with cutaneous manifestations. The patient presented with well-demarcated cellulitis (Figure 1). Histologic sections of skin demonstrated an unremarkable epidermis. In the dermis, there was a mixed inflammatory cell infiltrate surrounding numerous yeast-like fungal organisms that, when highlighted with mucicarmine and Fontana-Masson stains, were consistent withCryptococcus (Figure 2). Fungal culture of skin biopsy grew Cryptococcus neoformans. Serum cryptococcal antigen from day 3 was positive. Cerebrospinal fluid (CSF) obtained on day 3 revealed 7 white blood cells/ mm, 378 red blood cells/mm, glucose of 51 mg/dL, and protein of 41 mg/dL and was positive by cryptococcal lateral flow assay. The CSF Gram stain demonstrated fungal organisms, and culture grew C. neoformans 4 days later. Blood cultures obtained on hospital day 2 also grew C. neoformans on hospital day 7. A diagnosis of disseminated cryptococcosis with cutaneous involvement was made. Cryptococcosis is a serious infectious complication in recipients of solid organ transplant (SOT). Cryptococcus neoformans, a basidiomycetous, encapsulated yeast, has been identified in soil samples worldwide, particularly in areas contaminated by bird or pigeon droppings. The estimated incidence of cryptococcosis in SOT recipients is 1.56% (range, 0.45%–4.1%) [1, 2]. Cutaneous cryptococcosis in SOT typically arises from hematogenous spread following primary pulmonary infection, although direct skin inoculation has been reported [3]. Early data on cutaneous cryptococcal disease was limited to case reports and case series [2], but in a recent prospective SOT cohort study, cutaneous cryptococcosis was the third most common manifestation [4]. It was the most common manifestation in a case series of liver transplant recipients receiving tacrolimus [5], and patients receiving tacrolimus have been shown to have more cutaneous involvement than patients receiving non-tacrolimusbased immunosuppression [2]. Cutaneous manifestations of cryptococcosis are incredibly varied and include acneform lesions, purpura, papules, vesicles, nodules, tumors, abscess, ulcers, sinus tracts, plaques resembling ecchymoses, and superficial granulomas [6]. SOT patients with cryptococcal cutaneous disease often present with cellulitis [2, 4], and lower extremity involvement is most common [4], with multiple sites involved Figure 2. Skin biopsy (original magnification ×600). Fontana-Masson stain revealing melanin precursors in the yeast cell wall and accentuating the variable yeast size and morphology (red arrows) and narrow-based budding (yellow arrows). Figure 1. Photograph of the lower extremities showing well-demarcated cellulitis diagnosed as cutaneous cryptococcosis.