Authors: Assoc Prof Patrick Emanuel, Dermatopathologist, Auckland, New Zealand, 2013.
Infection of the dimorphic fungus, Sporothrix schenckii (sporotrichosis) usually occurs following percutaneous implantation of infected vegetable matter.
Histology of sporotrichosis
In sporotrichosis, sections show epidermalhyperplasia overlying a marked acute and chronicinflammatory response (figure 1). Higher power shows the inflammationinfiltrates the overlying epidermis (figure 2). The infiltrate is polymorphous with giant cells, histiocytes, and focalneutrophilicmicroabscess formation (figure 3). Careful examination of multiple sections is required to identify the causative organisms (figure 4, arrows).
The organisms may be yeast-like, elongated or rarely hyphal. “Sporothrix asteroids” are densely eosinophilic yeast forms with a surrounding ray of eosinophilic material (figure 4, arrows)