Photo Quiz: The Black Mold

A 58-year-old Indian male with end-stage kidney disease from presumed glomerulonephritis underwent a deceased-donor renal transplant in January 2018. Induction immunosuppression included basiliximab, thymoglobulin, and steroids due to high immunological risk. Maintenance immunosuppression included prednisolone at 10 mg daily, tacrolimus (calcineurin inhibitor) at 2 mg daily, and mycophenolic acid at 720 mg once in the morning and 540 mg once at night. The patient received cytomegalovirus (CMV) prophylaxis with valganciclovir for 6 months, as both the donor and recipient were CMV IgG positive, and trimethoprim-sulfamethoxazole prophylaxis against Pneumocystis pneumonia.

Eleven months after the transplant, he presented with an isolated, painless soft tissue plaque over his left elbow, progressively enlarging over 3 months, with purulent discharge from a sinus. He had no fever, constitutional symptoms, or other systemic complaints. He worked as a security guard. There was no history of penetrative trauma, animal bites, acupuncture, or use of alternative medicine.

On examination, a hyperpigmented, brown, verrucous plaque was seen on the medial aspect of the left elbow, with pus extruding from a sinus (Fig. 1A). The elbow had full range of motion, and there was no effusion or warmth. The renal graft was nontender, and examination of the rest of the systems was unremarkable.

FIG 1.

(A) Isolated hyperpigmented, brown, erythematous, verrucous plaque on left elbow with discharging sinus. (B) Multinucleated giant cell with dematiaceous fungal elements (arrow) displaying short-beaded hyphae (total magnification, ×400; hematoxylin and eosin stain). (C) Fungal elements displaying short-beaded hyphae (arrow) and yeast forms (arrowhead) (total magnification, ×400; Grocott’s methenamine silver stain).

He was prescribed amoxicillin-clavulanic acid for a week, with no improvement. Ultrasound of the lesion showed a small subcutaneous lobulated collection. Skin biopsy was undertaken. The histology showed a nonnecrotizing granulomatous infiltrate with epithelioid histiocytes in the dermis, multinucleated giant cells, and neutrophilic collections. Pigmented fungal elements, mainly in the form of small yeast forms and torulose hyphae (hyphae that are swollen and constricted at intervals, resulting in a beaded appearance), were seen. No acid-fast bacilli were seen, and the dermis was slightly acanthotic (Fig. 1B and C). There was no growth on bacterial or mycobacterial cultures. Fungal cultures on Sabouraud dextrose agar with chloramphenicol (Thermo Fisher, Waltham, MA) demonstrated growth at 30°C after 3 days’ incubation and at 37°C after 8 days’ incubation. The mold was darkly pigmented, with a suede-like texture. Microscopically, septate hyphae giving rise to torulose hyphae were seen. Annellides were also seen, with numerous conidia clustered at the tips. Other characteristics of the mold included absence of growth at 40°C and 15% salinity, with growth in 0.4% cycloheximide (Mycosel agar; Becton, Dickinson, Franklin Lakes, NJ). Excision of the lesion was subsequently performed, which revealed fungal organisms with yeast forms and torulose hyphae. The patient was started on a course of itraconazole at 200 mg once per day, and the tacrolimus dose was reduced to avoid drug toxicity.

For answer and discussion, see https://doi.org/10.1128/JCM.02195-20 in this issue.