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Case Reports

Abstract

Trichosporon spp. cause life-threatening infections that can affect children with hematologic malignancies. Prompt diagnosis through early clinical suspicion with confirmed molecular microbiology can significantly impact the outcome in patients with LCH. Due to the rarity of this infection, data are limited; however, it appears that when no hematologic malignancy is known in the patient, the presence of HLH secondary to Trichosporon is highly indicative of an undetected malignancy and warrants further workup. Herein, we present a case of a 2-year-old female with a febrile illness and pancytopenia who revealed five out of eight criteria for the diagnosis of HLH. Further testing found a positive Histoplasmosis antigen in the urine, and HLH secondary to Histoplasmosis was suspected. However, a negative serum antigen questioned the significance of the positive urine antigen. The patient developed a maculopapular rash and deep-seated cutaneous nodules, concerning for cutaneous Histoplasmosis versus a cutaneous manifestation of HLH or a lymphoproliferative malignancy. Examination of the biopsy revealed lobular panniculitis with dense “bean bag” histiocytes consistent with cytophagic histiocytic panniculitis. GMS stain revealed branched septate fungal hyphae and spores in the deep subcutaneous tissue, and PCR sequencing revealed Trichosporon spp. Despite initially normal bone marrow biopsies, repeat bone marrow testing showed a BRAF V600E mutation, concerning for LCH. This case highlights HLH secondary to Trichosporon, which was undetected prior to the biopsy. This process preceded the diagnosis of LCH, emphasizing the importance of skin biopsy in patients with HLH and skin manifestations to ensure timely treatment initiation.