Chronic superficial ulcers on the trunk.

Case

A 62-year-old man presented with several painful superficial ulcers on the trunk that began to expand slowly 1 year after inguinal hernia surgery. Physical examination demonstrated 5 ulcerative plaques on a violaceous base with overlying crust (Figs 1 and 2). A punch biopsy was performed, and tissue bacterial, fungal, and acid-fast bacilli cultures demonstrated no growth.

Fig 1

Fig 2

Question 1: Which of the following is the best diagnosis?

Superficial granulomatous pyoderma (SGP)

Ecthyma

Blastomycosis-like pyoderma

Chromomycosis

Factitious ulcer

Answer:

SGP – Correct. SGP is an uncommon variant of pyoderma gangrenosum (PG) characterized by slowly progressive superficial ulcers with vegetative margins and a clean granulating base. Unlike classic PG, SGP most commonly occurs on the trunk and is not significantly associated with systemic conditions.

Ecthyma – Incorrect. Ecthyma is a deep, ulcerative version of impetigo that is characterized by punched-out ulcers, most commonly observed on the lower extremities. The most commonly implicated bacteria include Streptococcus pyogenes and Staphylococcus aureus.

Blastomycosis-like pyoderma – Incorrect. Blastomycosis-like pyoderma is characterized by large verrucous plaques with pustules and an elevated border and is most commonly observed on the distal extremities.

Chromomycosis – Incorrect. Chromomycosis most often presents as a solitary verrucous nodule or plaque on an acral anatomic site.

Factitious ulcer – Incorrect. Factitious ulcers often demonstrate irregular or geographic borders and are induced by patients who assume the sick role without secondary gain.

Question 2: What is the most common anatomic site observed in this disorder?

Trunk

Extremities

Face

Anogenital region

Head and neck

Answer:

Trunk – Correct. SGP most commonly occurs on the trunk. Disseminated disease affects multiple anatomic sites.

Extremities – Incorrect. Classic ulcerative PG typically affects the lower extremities.

Face – Incorrect. While SGP is rarely reported on the face, this is not the most common anatomic site. SGP on the face appears to be refractory to topical and systemic corticosteroids.

Anogenital region – Incorrect. The anogenital region is rarely described in SGP.

Hands and neck – Incorrect. This is not a typical location for SGP.

Question 3: Which of the following descriptions reflects the histopathologic findings in this disorder?

Necrotic epidermis, ulcer, and sparse inflammation

Pigmented yeast with internal transverse septae

Ulceration with dense neutrophilic infiltrate and dermal necrosis

Layered suppurative granuloma with necrosis and suppuration surrounded by histiocytes and plasma cells, along with overlying epidermal hyperplasia

Pseudoepitheliomatous hyperplasia with neutrophilic abscesses and scar-like fibrosis

Answer:

Necrotic epidermis, ulcer, and sparse inflammation – Incorrect. These are nonspecific findings typically observed in factitious ulcer.

Pigmented yeast with internal transverse septae – Incorrect. Medlar or sclerotic bodies undergo binary fission and are characteristic of chromomycosis.

Ulceration with dense neutrophilic infiltrate and dermal necrosis – Incorrect. This describes findings present in classic ulcerative PG, which lacks the layered suppurative granuloma typical of SGP.1, 2, 3, 4

Layered suppurative granuloma with necrosis and suppuration surrounded by histiocytes and plasma cells, along with overlying epidermal hyperplasia – Correct. While nonspecific, these findings are consistent in SGP.1, 2, 3, 4

Pseudoepitheliomatous hyperplasia with neutrophilic abscesses and scar-like fibrosis – Incorrect. Blastomycosis-like pyoderma demonstrates these features; isolation of a pathogenic organism such as Staphylococcus aureus is required for diagnosis.

Conflicts of interest

None disclosed.