CHRONIC LUPOID LEISHMANIASIS - EVALUATION BY POLYMERASE CHAIN-REACTION

Background: The cutaneous lesions in chronic lupoid leishmaniasis rese mble those of lupus vulgaris, both clinically and histologically. The differential diagnosis is difficult and may depend on the detection of a few Leishmania amastigotes in the histologic sections, the growth o f the promastigotes in cultures, or the identification of amastigotes by other techniques. Polymerase chain reaction was used to detect Leis hmania amastigote DNA in tissue samples obtained from 65 patients with chronic lupoid leismaniasis, and the results were confirmed by Southe rn blot analysis. Observations: The histologic findings of a predomina ntly epithelioid cell granuloma surrounded by lymphocytic infiltrate i n chronic lupoid leishmaniasis are very similar to those observed in l upus vulgaris. Extensive histologic examination of the sections in thi s series revealed occasional macrophages containing a few amastigotes in only 12 cases. Cultures in NNN medium yielded Leishmania promastigo tes in 20 cases. Polymerase chain reaction studies using a Leishmania- specific primer identified Leishmania DNA in 30 of 63 cases, and those using a Mycobacterium tubeuculosis primer were found to be negative f or mycobacteria in 47 cases tested, including 11 cases with a positive tuberculin skin reaction. Conclusions: The histologic findings in chr onic lupoid leishmaniasis resemble those of lupus vulgaris. Polymerase chain reaction studies were useful in identifying amastigotes in 30 ( 47.6%) of 63 cases. This study confirms the presence of DNA molecules of Leishmania amastigotes in samples of formalin-fixed, paraffin-embed ded granulomatous tissue obtained from patients with chronic lupoid le ishmaniasis.