1. Presented by Kelly Craven MD, PhD and reviewed by Sean Zhang MD, PhD

Clinical Vignette

An adult patient presented to the doctor's office with lower extremity pain. Upon examination, they were found to have a large annular plaque with raised, scaly erythematous borders. They remembered it started as a tiny little spot after outdoor work several years ago and that is has now spread quite a bit over the last few months. Vital signs are stable and a CBC is within normal limits, but the automated differential shows an increased absolute eosinophil count at 0.62 K/cu mm (0.12-0.3 K/cu mm). A CT scan of the lesion shows exophytic skin masses which do not extend into the subcutaneous tissue and prominent adenopathy. A skin biopsy showed pseudoepitheliomatous hyperplasia with intraepidermal microabscesses.









Fig 1: Skin biopsy (H&E). Arrows highlight intraepidermal microabscesses.





Fig 2: Skin Biopsy (GMS). A GMS stain highlights a minute cluster of fungal organisms within the superficial stratum corneum (top: low power view with organisms between the dots, bottom: high power view with arrow highlighting yeast forms with cigar shape).



Fig 3: Fungal culture .



Fig 4: Slide prep shows a mold form with conidia in clusters or flowerettes.

Question:

What is the causative organism?