Skin biopsy: a pillar in the identification of cutaneous Mycobacterium tuberculosis infection.
BACKGROUND
The present study aimed to establish the frequency and clinical characteristics of cutaneous tuberculosis among Mexican adult patients.


METHODS
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 95 cases (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.
Facultad de Medicina, UNAM, Hospital General de México, Mexico. drhernandezsolis@yahoo.com.mx
Alejandro
A
Hernández Solis
Norma Estela
NE
Herrera González
Fernando
F
Cazarez
Patricia
P
Mercadillo Pérez
Hiram Olivera
HO
Olivera Diaz
Alejandro
A
Escobar-Gutierrez
Ileana
I
Cortés Ortíz
Heleodora
H
González González
Arturo
A
Reding-Bernal
Raúl Cícero
RC
Sabido
D000293:Adolescent; D000328:Adult; D000368:Aged; D000995:Antitubercular Agents / Q000008:administration & dosage; D001431:Bacteriological Techniques; D001706:Biopsy / Q000379:methods*; D003470:Culture Media / Q000737:chemistry; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D006651:Histocytochemistry; D006801:Humans; D008297:Male; D008800:Mexico; D008853:Microscopy; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction / Q000379:methods; D012867:Skin / Q000382:microbiology* / Q000473:pathology; D016896:Treatment Outcome; D014382:Tuberculosis, Cutaneous / Q000175:diagnosis* / Q000382:microbiology / Q000473:pathology; D055815:Young Adult
D000995:Antitubercular Agents; D003470:Culture Media; D004251:DNA Transposable Elements; D004269:DNA, Bacterial