A physician-validated, board-style question from the Active Transport QBank. Try it, then check the reasoning for every option.
A 42-year-old woman with well-controlled HIV on antiretroviral therapy comes to the physician because of a 2-week history of a painless lesion on her right calf. Many years ago, she had a maculopapular rash over her trunk, palms, and soles that resolved spontaneously. Physical examination shows a 4-cm firm, non-tender, indurated ulcer with a moist, dark base and rolled edges. There is a similar lesion at the anus. Results of rapid plasma reagin testing are positive. Which of the following findings is most likely on microscopic examination of these lesions?
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A
Epidermal hyperplasia with dermal lymphocytic infiltrateIncorrect. Epidermal hyperplasia with dermal lymphocytic infiltrate is nonspecific and characteristic of secondary syphilis or other reactive dermatoses, not the gummas of tertiary syphilis.
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B
Lichenoid hyperplasia with superficial neutrophilic infiltrateIncorrect. Lichenoid hyperplasia with neutrophilic infiltrate suggests psoriasiform/neutrophilic dermatoses, not a syphilitic gumma.
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C
Ulcerated epidermis with plasma cell infiltrateIncorrect. Plasma-cell-rich ulcerated epidermis is the histology of the primary chancre, not the granulomatous gumma of tertiary syphilis.
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D
Coagulative necrosis surrounded by fibroblast and macrophage infiltrateCorrect. Coagulative necrosis surrounded by fibroblasts and macrophages describes a gumma - the granulomatous lesion of tertiary syphilis seen years after the primary chancre and secondary rash.
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E
Pseudoepitheliomatous hyperplasia with eosinophilic infiltrateIncorrect. Pseudoepitheliomatous hyperplasia with eosinophils is characteristic of fungal or parasitic infections, not the granulomatous gumma of tertiary syphilis.
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Answer: D. An HIV-positive patient with a remote history of resolved maculopapular palm-and-sole rash (classic secondary syphilis) now presents with a painless, firm, indurated ulcer with rolled edges and a similar perianal lesion, plus a positive RPR. This is gummatous (tertiary) syphilis - a granuloma-like late manifestation occurring years to decades after primary infection.
Gummas are noninfectious granulomatous lesions caused by a delayed hypersensitivity response to residual treponemes. On histopathology, they show coagulative necrosis surrounded by epithelioid macrophages, fibroblasts, and a perivascular lymphoplasmacytic infiltrate - similar to a tuberculous granuloma but typically with prominent plasma cells. They can involve skin, bone, liver, or any organ and may ulcerate as in this patient.
Distinguishing histology: primary syphilis (chancre) shows ulcerated epidermis with a dense plasma cell infiltrate (choice C is the chancre histology, not the gumma); secondary syphilis shows perivascular plasma cells with psoriasiform epidermal hyperplasia. The temporal sequence (primary chancre years ago, secondary rash that resolved, now late lesion in HIV) together with the morphologic description points to a gumma, which is the coagulative necrosis option.
**Why each option:**
**A.** Epidermal hyperplasia with dermal lymphocytic infiltrate is nonspecific and characteristic of secondary syphilis or other reactive dermatoses, not the gummas of tertiary syphilis.
**B.** Lichenoid hyperplasia with neutrophilic infiltrate suggests psoriasiform/neutrophilic dermatoses, not a syphilitic gumma.
**C.** Plasma-cell-rich ulcerated epidermis is the histology of the primary chancre, not the granulomatous gumma of tertiary syphilis.
**D.** Coagulative necrosis surrounded by fibroblasts and macrophages describes a gumma - the granulomatous lesion of tertiary syphilis seen years after the primary chancre and secondary rash.