Diagnostic challenges of single plaque-like lesion paucibacillary leprosy

The diagnosis of single-lesion paucibacillary leprosy remains a challenge. Reviews by expert dermatopathologists and quantitative polymerase chain reaction (qPCR) results obtained from 66 single-plaque biopsy samples were compared. Histological findings were graded as high (HP), medium (MP) or low (LP) probability of leprosy or other dermatopathy (OD). Mycobacterium leprae-specific genes were detected using qPCR. The biopsies of 47 out of 57 clinically diagnosed patients who received multidrug therapy were classified as HP/MP, eight of which were qPCR negative. In the LP/OD (n = 19), two out of eight untreated patients showed positive qPCR results. In the absence of typical histopathological features, qPCR may be utilised to aid in final patient diagnosis, thus reducing overtreatment and delay in diagnosis.

Diagnóstico da hanseníase paucibacilar com lesão única / Leprosy diagnosis with single plaque skin lesions

Introdução: Apesar do recente declínio dos coeficientes de detecção de casos novos, a hanseníase permanece endêmica no Brasil e em outros países do mundo. O diagnóstico da doença se baseia nos aspectos clínicos, embora o índice baciloscópico e a histopatologia sejam usados como suporte para o diagnóstico. Nas formas paucibacilares, bacilos são raramente detectados e o exame histopatológico pode ser inconclusivo. Neste estudo,analisamos os aspectos clínicos e histopatológicos de pacientes com suspeita de hanseníase paucibacilar e estabelecemos a contribuição do PCR no manejo clínico destes casos.Pacientes e Métodos: Foram estudados 66 pacientes com lesão cutânea única em placa,atendidos no Ambulatório Souza Araújo (ASA) da Fundação Oswaldo Cruz, Rio de Janeiro,Brasil, no período de janeiro de 2008 a dezembro de 2011. Dois patologistas independentes,que não tinham informações sobre a história clínica dos pacientes, realizaram a reanálisehistopatológica. Os pacientes foram classificados como Alta (A), Média (M) e Baixa (B)probabilidade do diagnóstico de hanseníase ou outras dermatoses (O). O DNA foi extraído defragmentos de biópsias de pele e os níveis de M. leprae Ag85B e 16S rDNA foram estimadosusando a amplificação por PCR quantitativo (qPCR). Resultados: O qPCR foi positivo em 46/66 (69.7 por cento) das amostras de pele. Dos 66 pacientes, 57 (86.3 por cento) tinham recebidotratamento com poliquimioterapia (PQT) baseado nos aspectos clínicos e histopatológicos. Aassociação entre o resultado do PCR e a variável tratamento mostrou que entre os 19pacientes classificados como L+O, 2 pacientes com PCR positivo não tinham recebidotratamento e 6 pacientes com PCR negativo tinham sido tratados com PQT por 6 meses.Conclusão: Concluímos que o qPCR é uma ferramenta útil para o diagnóstico e o manejoclínico dos pacientes com suspeita de hanseníase paucibacilar, nos casos em que ahistopatologia não é conclusiva...

Background: Despite recent decline in detection rates, leprosy remains endemic in Brazil andin others countries around the world. Frequently, the disease diagnosis is based only onclinical aspects, although the bacteriological index in skin smears and histopathologicalexamination are used to support conclusions. In paucibacillary forms, bacilli are rarelydetected, and histopathological examination may not be conclusive. In this study, we analisedthe clinics and histopathological aspects of patients suspected of paucibacillary leprosy andtry to establish the contribution of PCR to the clinical management of these cases. Methods:We evaluated 66 patients with single-plaque skin lesions who attended the Leprosy OutpatientUnit of Oswaldo Cruz Foundation, Rio de Janeiro, Brazil, between 2008 and 2011. Twoindependent pathologists who were blinded to the patients’ clinical details performedpathological reanalysis of slides. Patients were classified as High (H), Medium (M), and Lowprobability (L) for the diagnosis of leprosy or another dermatosis (O). DNA was extractedfrom the fragments of skin biopsies, and the levels of M. leprae Ag85B and 16S rDNA wereestimated using qPCR amplification. Findings: The qPCR was positive in 46/66 (69.7 percent) ofskin samples. Out of 66 patients, 57 (86.3 percent) received multidrug therapy (MDT) based onclinical and histopathological examination. The association between previous treatment andqPCR results showed that among 19 patients classified as L+O, 2 qPCR-positive patientswere not treated, whereas 6 patients with negative qPCR results were treated with MDT for 6months. Conclusion: In conclusion, qPCR is a useful tool to diagnosis and clinicalmanagement in suspected cases of paucibacilary leprosy in cases with inconclusivehistopathology...