PMC9755212_01
Panel (A) Ulceration (4 cm in diameter) within a psoriatic plaque on the right abdomen of the obese patient receiving anti-TNF therapy (adalimumab). Panel (B) Up to 10 cm pseudolymphomatous tumor surrounded by a psoriatic plaque on the right knee of the patient caused by cutaneous Leishmania infantum infection under anti-TNF therapy and erythematosquamous plaque on the right tibia. Panel (C) Erythematosquamous plaque on the right abdomen of the patient after cessation of adalimumab therapy. Panel (D) Erythematosquamous plaque on the right knee and shin of patients after cessation of adalimumab therapy.
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F1
Moreover, the patient showed erosive and partly ulcerating plaques and nodules, some of them covered by distinct brown crusts, at the right forearm, right knee, left flank and the abdomen (Figures 1A,B). In hematoxylin-eosin (Figure 1C), Giemsa (Figure 1D) and Feulgen stains, intracellular Leishmania amastigotes with kinetoplasts were seen, which were identified by culture, miniexon PCR and restriction fragment length polymorphism-analysis as L. infantum.
Panel (A) Histopathology shows a dense nodular, perivascular, periadnexal and interstitial infiltration of mainly T-cells and lymphocytes (Hematoxylin-eosin stain, x25) Panel (B) Immunohistochemistry with CD3 antibodies (x25). Histopathology shows multiple intracellular amastigotes with peripheral nuclei and kinetoplasts in Hematoxylin-eosin stain Panel (C) and in Giemsa stain Panel (D) (x400 magnification each).
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F2
Two repeat biopsies and histologies from morphologically different lesions on the right forearm and right flank revealed an interface dermatitis with pseudolymphomatous infiltrates, thickening of the epidermis, follicular hyperparakeratosis, and perivascular, periadnexal, superficially accentuated lymphocytic infiltrates with a preponderance of T cells (Figures 2A,B). Tissue clonality analyses demonstrated polyclonal IgH and TCR gamma chain gene expression, thus excluding lymphoma. The therapy with adalimumab was stopped, while treatment with methotrexate was continued (Figure 2).
Time course of the patient's medical history, treatment, and Leishmania infantum infection. The red star marks the time of detection of L. infantum in skin biopsies. PsA, psoriasis arthropathica.
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F3
During regular medical follow-up for almost 5 years the clinical condition of the patient remained stable (Figure 3).