Multifocal Soft Tissue Cryptococcosis In A Renal Transplant Recipient: The Importance Of Suspecting Atypical Pathogens In The Immunocompromised Host

Cryptococcal infection has been documented in 2.8% of solid- organ transplant recipients, with the median time to disease onset being 21 months. Renal transplant recipients account for the majority of cases. Most patients present with central nervous system or disseminated disease, with only a minority having cutaneous manifestations. We present the case of a 47-year-old female renal transplant recipient who presented with refractory acute cellulitis 7 months after transplant. She had received thymoglobulin induction and was on a maintenance immunosuppressive regimen of tacrolimus, mycophenolic acid, and prednisone (5 mg/d). She did not respond to broad-spectrum antibacterial therapy for presumed bacterial cellulitis. Skin and soft tissue biopsies subsequently showed the presence of yeast; Cryptococcus neoformans was recovered in culture. Blood cultures, chest radiography, and cerebrospinal fluid sampling were negative, which resulted in a diagnosis of multifocal soft tissue cryptococcosis, a form of disseminated disease. Serum cryptococcal antigen testing was strongly positive (>= 1:2560). The patient's immunosuppression was reduced, and she received treatment with liposomal-amphotericin B and flucytosine for 2 weeks, which resulted in symptomatic improvement. This was followed by 1 year of consolidation and subsequent maintenance therapy with fluconazole. This case should increase awareness of the broader differential diagnosis of soft tissue infection in immunocompromised patients. Her case mimicked bacterial cellulitis, which delayed administration of effective therapy. Although our patient was initially diagnosed via biopsy, early clinical suspicion and serum cryptococcal antigen testing can lead to the correct diagnosis more rapidly. As transplant patients return to their community providers, heightened vigilance for unusual infections and presentations is warranted. The possibility of a cryptococcal cause for acute soft tissue infection should be considered, even in the absence of pulmonary or central nervous system involvement.