An atypical cause of sporotrichosis in a cat

Abstract

A nine-year-old domestic cat from Melbourne, Australia, presented with a non-ulcerated nodule on its nasal bridge. A fungal infection of the subcutis was diagnosed based on histopathology and culture of a white mould, which was identified as Sporothrix pallida complex by ITS1-5.8S-ITS2 and β-tubulin gene sequencing. The cat was treated by cytoreduction, itraconazole and subsequently posaconazole, which eventually resulted in regression of residual infected tissues and clinical resolution.

Keywords: Itraconazole; Posaconazole; Sporothrix pallida; Sporotrichosis.

Fig. 1

Side and front view of the cat immediately following debulking surgery. Residual swelling of the bridge of the nose is present.

Fig. 2

(Left) H&E-stained histology section showing intracellular eukaryotic organisms (arrows) as well as some scattered extracellular organisms. (Right) PAS-stained section revealing hyphae and conidia and/or yeast forms. The measure bar in each photo is 10 µm.

Fig. 3

(Top) Colony morphology on Sabouraud's dextrose agar after 14 days at 26 °C, and (bottom) lactophenol cotton blue wet preparation showing clavate conidia typical of Sporothrix spp. The measure bar is 5 µm.