Skin biopsy: a pillar in the identification of cutaneous Mycobacterium tuberculosis infection (original) (raw)

Authors

Alejandro Hernández Solis Hospital General de México y Facultad de Medicina, UNAM, Mexico
Norma Estela Herrera González Sección de Posgrado, Escuela Superior de Médicina, IPN, Mexico
Fernando Cazarez Instituto de Diagnóstico y Referencia Epidemiológica, Secretaria de Salud, Mexico
Patricia Mercadillo Pérez Hospital General de México y Facultad de Medicina, UNAM, Mexico
Hiram Olivera Diaz Instituto de Diagnóstico y Referencia Epidemiológica, Secretaria de Salud, Mexico
Alejandro Escobar-Gutierrez Instituto de Diagnóstico y Referencia Epidemiológica, Secretaria de Salud, Mexico
Ileana Cortés Ortíz Instituto de Diagnóstico y Referencia Epidemiológica, Secretaria de Salud, Mexico
Heleodora González González Hospital General de México y Facultad de Medicina, UNAM, Mexico
Arturo Reding-Bernal Hospital General de México y Facultad de Medicina, UNAM, Mexico
Raúl Cícero Sabido Hospital General de México y Facultad de Medicina, UNAM, Mexico

DOI:

Keywords:

cutaneous tuberculosis, polymerase chain reaction (PCR), Mycobacterium tuberculosis

Abstract

Introduction: The present study aimed to establish the frequency and clinical characteristics of cutaneous tuberculosis among Mexican adult patients.

Methodology: Ninety-five patients with clinically compatible lesions to cutaneous tuberculosis participated in the study. All patients were HIV negative and none of them had previous anti-TB treatment. A skin biopsy was taken from every patient suspected of having tuberculosis, and a histopathologic examination was performed as follows: Ziehl-Neelsen staining; culturing of mycobacteria by Löwenstein-Jensen (L-J) medium; Mycobacteria Growth Indicator Tube detection via BACTEC (MGIT-360); and polymerase chain reaction (PCR) with the sequence of insertion IS6110 for Mycobacterium tuberculosis complex.

Results: Tuberculosis was confirmed in 65 out of 95cases (68.4%). Identified lesions were scrofuloderma (42 cases, 64.6%); lupus vulgaris (12 cases, 18.4%); warty tuberculosis (six cases, 9.2%); and papulonecrotic tuberculoid (five cases; 7.7%). The Ziehl-Neelsen staining was positive for acid fast bacilli in nine cases (13.8%) and 48 patients were positive for the PCR amplification (73.8%). All skin biopsies resulted positive for tuberculosis. A positive clinical response to the specific treatment was considered a confirmation for tuberculosis. The noninfectious etiology corresponded to 30 cases (31.6%).

Conclusions: Tuberculosis in developing countries is still an important cause of skin lesions which must be studied via histopathological examination and culture due to their low bacillary load. A PCR test is necessary to obtain faster confirmation of the disease and to establish an early, specific and effective treatment.