Cutaneous leishmaniasis (CL) is an endemic infectious disease, representing a large public health problem worldwide1. In Brazil, an average of 30,000 cases are reported annually. Usually, CL is transmitted by infected phlebotomine sand fly bites, and a subclinical infection in the host has been proven1. There are a few reports that describe unusual modes of parasite infection, such as through direct contact, rat bites, accidental laboratory inoculation2,3, localized trauma4,5, and the use of immunomodulators such as anti-tumor necrosis factor (TNF)-alpha6,7. Here, we report a case of American tegumentary leishmaniasis (ATL) following electrocoagulation for a seborrheic keratosis skin lesion.
A previously healthy 59-year-old female Brazilian biologist who often travels to ATL endemic areas underwent an electrocoagulation procedure to remove two hyperchromic squamous stable lesions, that appeared after 50 years of age, when the patient was no longer traveling to endemic areas. Clinically and dermoscopically, both lesions were diagnosed as seborrheic keratosis: one on the nose and the other on the thigh. Two months later, with no reported travel to endemic ATL regions, erythematous nodules emerged on the surgical scars. One month later, the nodules were removed and sent for histopathology, fungal, bacterial, and mycobacterial direct examinations and cultures, which were reported to be negative. Only 6 months later and after the third biopsy, the histopathology showed a lymphohistiocytic infiltrate with granulomas and multinucleated cells, and some rare roundish forms compatible with amastigotes, which were confirmed by immunohistochemistry. A skin fragment tested positive for Leishmania culture, and the parasite was identified as L. (V.) braziliensis using a polymerase chain reaction (PCR) assay and restriction enzyme analysis8. Montenegro skin test and indirect immunofluorescence assay results were positive and human immunodeficiency virus (HIV) serology test results were negative. She was treated with 2g of liposomal amphotericin B and had completely healed by the time of this report (Figure 1 and Figure 2).
Here, we reported the case of an immunocompetent patient with no previous sign of leishmaniasis. After undergoing a very common dermatological procedure for the removal of two well-defined benign lesions on distant parts of the body, after a short period of time, she presented with simultaneous CL lesions on both sites. This presentation reinforces the idea that electrocoagulation may have triggered ATL.
In the Americas, the main species that causes ATL is L. (V.) braziliensis8. Previous studies of Leishmaniaserology, Montenegro skin tests, and the presence of Leishmania DNA identified using PCR techniques have shown that in Brazilian endemic areas, 10% of the population has subclinical infections7. It is also important to note that there are some reported cases of primary or secondary CL lesions after localized trauma, and these lesions can appear months later4,5. In our experience of more than 2,000 cases of ATL, we have observed 3 cases triggered by trauma: one after a bicycle trauma on the ankle cause by L. (L.) amazonensis9; one after a snake bite; and one after a laser hair removal procedure. In addition, previous studies in murine models infected with Leishmania support the possibility of metastatic cutaneous lesions at sites of trauma5.
Considering the concepts presented above, we may consider that trauma generates an inflammatory cascade that favors Leishmania dissemination and lesion formation in previously infected patients. This hypothesis is supported by the local formation of immunosuppressive cytokines and transformation of growth factor-p that exacerbates lesion development. Previous studies in Balb-c mice infected with L. (V). braziliensis have shown that these factors could reactivate the subclinical infection10,11. Our patient was a biologist that lived for 9 years in Rio de Janeiro, Brazil, and travelled several times to endemic regions. She presented typical lesions of seborrheic keratosis, the diagnosis of which was confirmed by clinical and dermatoscopy examinations, and that appeared when she no longer travelled.
In this case and in others found in the literature, we note that the clinical presentation is usually characterized by nodules, plaques, and papules that are not typical unique ulcers, making the diagnosis even more difficult. It is important to differentiate this case, wherein an immunocompetent patient had a previous subclinical Leishmaniainfection, from the previously referenced cases in which the parasite was inoculated by agents other than phlebotomine sand flies2,3. It is believed that disease activation was triggered by the electrocoagulation procedure, characterized as the known locus minoris resistentiae phenomenon12.
Histopathology is the gold standard examination for the diagnosis of seborrheic keratosis, but those lesions are a part of dermatologists’ daily practice; seborrheic keratosis lesions exhibit unique clinical characteristics, with no malignant potential, and are cured by electrocoagulation procedures. In addition, dermatoscopy examinations are also commonly performed.
ATL is a dynamic disease, the pathophysiology of which is not well understood because of the continually changing environmental, demographic, and human behavioral factors. It is important for all physicians to be aware of the possibility of CL lesion onset at the sites of dermatological and aesthetical procedures in endemic and nonendemic areas, as the world is globalized and leishmaniasis is considered a re-emerging disease.