Eosinophil rich infiltrate in secondary syphilis a rare histopathological variant

Vidya D. Kharkar, Harish B. Rajendran


Secondary syphilis is a sexually transmitted infection, which is referred to as “the great imitator” and has a wide spectrum of clinical manifestations. Syphilis is classically associated with plasma cells and the presence of eosinophils usually argues against a diagnosis of syphilis. The differential diagnosis for eosinophil-rich skin lesions often includes a drug reaction, arthropod-bite reaction, allergic contact dermatitis, and a response to a helminth infestation. However, many unrelated entities, such as infections, neoplasms, and inflammatory dermatoses can have prominent eosinophilic infiltrate. We report a case of secondary syphilis which on histopathology showing psoriasiform hyperplasia with superficial perivascular infiltrate and on higher magnification these infiltrate were predominantly lymphohistiocytic along with the moderate amount of eosinophils with a paucity of plasma cells. This case report is presented to highlight the need for including secondary syphilis as one of the differential diagnoses in the presence of eosinophil-rich infiltrate when it is suspected clinically.


Secondary syphilis, Eosinophils, Histopathology

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