Enlarging erythematous plaque with multiple draining sinus tracts

Presenter: Ryan Jawitz, DO

Dermatology Program: St. Joseph Mercy Hospital

Program Director: Daniel Stewart, DO

Submitted on: October 15, 2010

CHIEF COMPLAINT: “Rash on the right hand”

CLINICAL HISTORY: A 78-year-old male presented with a 2-month history of an erythematous plaque on his right hand that started after gardening. The plaque was non-pruritic and non-painful but has been draining a purulent discharge for the last six weeks. His medical history included diabetes mellitus type 2, coronary artery disease, chronic obstructive pulmonary disease, hypertension, prostate cancer, and laryngeal cancer treated with radiation. The plaque was treated as cellulitis with both oral and IV antibiotics for the prior two months, however, it continued to enlarge.

PHYSICAL EXAM:
Physical examination revealed a large indurated and hyperkeratotic erythematous plaque covering his right wrist and dorsal forearm, which expressed copious amounts of pus from sinus tracts when pressure was applied. There was no streaking, tenderness, or arthralgia of the wrist joint.

LABORATORY TESTS:

The bacterial culture and gram stain were negative for organisms. Fungal culture grew Pseudoallescheria boydii.

DERMATOHISTOPATHOLOGY:

In the biopsy, there was a cyst-like cavity in the dermis lined by fragments of epithelium suggestive of a cyst wall with an adjacent suppurative and granulomatous inflammatory cell infiltrate. Neutrophils, macrophages, and multinucleated giant cells were noted in the infiltrate. A Periodic acid-Schiff (PAS) stain highlighted fungal elements in the multinucleated giant cells as well as in the areas of abscess formation.