The Diagnostic Utility of PCR in FFPE Skin Biopsies with Inconclusive Histopathology for Suspected Cutaneous Leishmaniasis: A Pilot Study from Colombia.

Cutaneous Leishmaniasis (CL) is a tropical disease endemic in many regions of Latin America. Its clinical diagnosis is often supported by histopathological analysis of skin biopsies; however, parasite detection by microscopy can be challenging, particularly in chronic or pauciparasitic lesions, leading to inconclusive results.

Objective: This study aimed to evaluate the utility of polymerase chain reaction (PCR) as a confirmatory diagnostic tool for CL in formalin-fixed, paraffin-embedded (FFPE) biopsies with inconclusive histopathology.

Methods: We analyzed 16 FFPE skin biopsy samples from patients with clinical suspicion of CL. All cases underwent routine histopathological evaluation using hematoxylin and eosin staining and were classified as inconclusive. DNA was extracted and PCR was performed, targeting the ITS1 and miniexon regions of Leishmania spp.

Results: PCR successfully amplified Leishmania DNA in 8 (50%) out of 16 samples when both targets were utilized, confirming infection. These findings highlight the additional benefits of molecular tools in cases with inconclusive histopathology, thereby enhancing diagnostic accuracy and enabling species-level identification in certain instances.

Conclusions: PCR proved to be a valuable diagnostic complement to histopathology in clinically and histologically suspected cases of CL without visible parasites. Its implementation may improve diagnostic accuracy and timely treatment in endemic areas.