Resident Dermatologist: Kevin Donnelly, MD

Attending Dermatologist: Susan Massick, MD

Dermatopathologist: Catherine Chung, MD


64 y.o. male with a history of undifferentiated mixed connective tissue disease on longterm methotrexate and prednisone presents with several week history of pain and swelling of his right hand, which progressed to ulcerations and necrosis (figures 1-2). He reports his hand is very painful with limited range of motion due to pain. He also reports new indurated, firm, erythematous purple nodules with deep tenderness on left and right thighs and right inner arm (not pictured). He endorses fever/chills and night sweats, but denies weight changes. Lesions failed to improve with systemic antibiotics, antivirals, and caspofungin. A skin biopsy was performed for further evaluation.

Figure 1: Right hand: Several punched out ulcers with surrounding erythema and erosions, tender to palpation

Figure 2: Punched erosion with surrounding erythema at the base of the 1st MCP. Several erosions on the 3rd digit. Ulcerations and dry gangrene at the tip of the 2nd digit. Superficial erosion and erythematous nodule of the hypothenar eminence

Punch biopsy demonstrates an infiltrate in the dermis that extends to the subcutaneous fat.

High power magnification demonstrates parasitized organisms within histiocytes (arrows)

Grocott Methamine Silver (GMS) stain decorates the parasitized organisms.

What is the most likely diagnosis?

  1. Disseminated histoplasmosis
  2. Autoimmune vasculitis
  3. Bacterial cellulitis
  4. Disseminated herpes simplex
Disseminated histoplasmosis