P265 Phaeohyphomycosis caused by Rhinocladiella similis mimicking Sporotrichosis

Abstract

Abstract Poster session 2, September 22, 2022, 12:30 PM - 1:30 PM Objective A case of phaeophyphomycosis caused by Rhinocladiella similis with a clinical picture simulating sporotrichosis is described. Methods A 34-year-old male patient, employed in a textile factory presented with multiple subcutaneous nodules on the lateral aspect of the dorsum of the left hand and left forearm. There was a history of mechanical trauma 1 year back. On examination, three to four verrucous ulcerative nodules clustered on the dorsum of the left hand were observed. A preliminary diagnosis of sporotrichosis was made and a punch biopsy was performed from the lesion and subjected to KOH examination, fungal culture, and histopathological examination. ITS sequencing was done to confirm the identity of the isolate. Results The skin punch biopsy from the lesion on the dorsum of the hand showed marked hyperkeratosis, papillomatosis, parakeratosis, acanthosis, and irregular elongation of rete ridges. No fungal structures and neutrophils were seen. On examination with 40% Potassium hydroxide round yeast-like cells were seen. An initial diagnosis of sporotrichosis was established. After 5 days, white to grayish colonies with aerial hyphae were observed on Sabouraud's dextrose agar which eventually turned greenish black on further incubation. Lactophenol cotton blue (LPCB) mount of the slide culture showed thin, hyaline, septate hyphae with oval conidia arranged in a bottle brush pattern around erect conidiophores and also directly arising from the hyphae. The pathogen was confirmed by ITS sequencing as R. similis. Patient was started on itraconazole 200 mg twice daily for 12 weeks. The patient is on regular follow-up and has shown gradual regression of the lesions indicating response to therapy. Conclusion Rhinocladiella similis infections have been reported chiefly from Brazil causing chromoblastomycosis. There have been no reports of infections due to this pathogen from the Indian subcontinent. This report presents the first case of R. similis as an agent of phaeohyphomycosis and calls for the need of a thorough evaluation of these cases so as to manage cases appropriately. It also underlines the need to study and redefine the ecological niche of this pathogen as well as its clinical spectrum.