A 50-year-old man presented with an annular plaque located on the medial aspect of the left lower extremity. The lesion was painless, ulcerated, and indurated, and had been present for approximately one year. There was no history of trauma to the site. The patient lived most of his life in Southwest Asia, but had no other significant travel history. He was otherwise healthy.
On physical examination, the patient had a large (3 × 6 cm) ulcer on his left lower extremity with a larger area of surrounding erythema (Figures 1 and 2). The ulcer was growing despite topical steroid treatment. More recently, a similar smaller ulceration appeared on the lateral aspect of his right lower extremity.
The answer is E: localized cutaneous leishmaniasis. Lesions occur on exposed skin as a result of Leishmania infection after inoculation from a sandfly bite. Leishmania infections often occur in troops returning to the United States after serving in the Middle East or Southwest Asia. The initial manifestation of a pink papule enlarges into a nodule or plaque, eventually becoming a painless, indurated, annular ulcer. The lesion heals over months to years and leaves an atrophic, depressed scar. Localized cutaneous leishmaniasis is oriented along skin creases, and causes inflammatory satellite papules and induration beneath the lesion.1
Histopathology, culture, or polymerase chain reaction can be used to diagnose localized cutaneous leishmaniasis. Determining the species can guide treatment, but success is variable.2
Mycobacterium fortuitum, M. chelonae, and M. abscessus are considered rapid-growing, atypical mycobacteria. They can cause a large fluctuant abscess, which progresses to a solitary ulcerated, indurated lesion. These infections often occur after a penetrating injury or a surgical procedure in immunosuppressed patients. Diagnosis is made with mycobacterial cultures from skin lesions.3
Basal cell carcinoma is typically a pearly white, dome-shaped papule with telangiectatic surface vessels. It can also present as a pigmented, superficial, scaly plaque; an ulcer with indurated borders; or a yellow, firm, ill-defined mass (morpheaform). Most basal cell carcinomas occur on the head and neck. It is associated with exposure to ultraviolet B light. Diagnosis is by biopsy.4
Cutaneous anthrax is caused by Bacillus anthracis. It begins as a painless, often pruritic papule that enlarges into a vesicle or bulla within 24 hours. The vesicle becomes hemorrhagic, followed by ulcer formation with a painless black eschar. Marked edema and erythema develop, often with associated satellite vesicles. The eschar usually falls off within two weeks. Cutaneous anthrax spontaneously resolves in 90% of patients. Diagnosis is made by Gram stain or culture; a full-thickness punch biopsy should be obtained for histology, polymerase chain reaction testing, and immunochemistry studies.5
Erythema induratum, a form of nodular vasculitis, presents as crops of tender, violaceous nodules and plaques on the posterior lower extremities that evolve over several weeks. The lesions often ulcerate and drain. The disorder is overwhelmingly more common in women, usually in middle age. Erythema induratum is a reaction usually associated with M. tuberculosis, Nocardia, Pseudomonas, and Fusarium infections; however, it can also be associated with thrombophlebitis, hypothyroidism, rheumatoid arthritis, Crohn disease, and chronic lymphocytic leukemia.6
|Atypical mycobacteria infection
|Mycobacterium fortuitum, M. chelonae, M. abscessus
|Large fluctuant abscess progressing to a solitary ulcerated, indurated lesion; often occurs at the siteof a penetrating injury or surgery
|Basal cell carcinoma
|Associated with exposure to ultraviolet B light
|Pearly white, dome-shaped papule with telangiectatic surface vessels or ulcer with indurated borders; located on the head and neck
|Painless, often pruritic papule that enlarges into a vesicle or bulla; black eschar and surrounding edema and erythema
|Reaction associated with multiple infections, usually M. tuberculosis, Nocardia, Pseudomonas, and Fusarium; also associated with thrombophlebitis, hypothyroidism, rheumatoid arthritis, Crohn disease, and chronic lymphocytic leukemia
|Crops of tender, violaceous nodules and plaques on the posterior lower extremities
|Localized cutaneous leishmaniasis
|Leishmania parasite, transmitted by sandfly vector
|Pink papule enlarges into a nodule or plaque, eventually becoming a painless, indurated, annular ulcer; usually occurs on exposed skin
The opinions and assertions contained herein are the private views of the authors and not to be construed as official or as reflecting the views of the U.S. Air Force, U.S. Army, and the Department of Defense.