PCR detection of Mycobacterium tuberculosis in necrotising non-granulomatous lymphadenitis using formalin-fixed paraffin-embedded tissue: a study in Thai patients.
BACKGROUND
Necrotising non-granulomatous lymphadenitis can be observed in several conditions, most notably infection (including tuberculosis, yersiniosis and nocardiasis), Kikuchi-Fujimoto disease and systemic lupus erythematosus.


OBJECTIVE
To evaluate the role of PCR in the detection of Mycobacterium tuberculosis in necrotising non-granulomatous lymphadenitis in Thai patients using formalin-fixed paraffin-embedded tissue.


METHODS
35 patient samples showing necrotising non-granulomatous lymphadenitis were subjected to PCR for detection of the IS6110 sequence of M tuberculosis. For comparison, sections were visually assessed for acid-fast bacilli using the Ziehl-Neelsen stain.


RESULTS
Among 35 cases of necrotising non-granulomatous lymphadenitis, a conclusive diagnosis could be reached in 23 cases: 15 cases of Kikuchi-Fujimoto disease, 6 of tuberculosis and 2 of systemic lupus erythematosus. Of the 6 cases of tuberculous lymphadenitis, 4 (66.6%) were detected by PCR in formalin-fixed paraffin-embedded tissue samples. PCR was positive in 6/12 of the remaining cases (50%) in which a definitive diagnosis could not be reached by other methods.


CONCLUSIONS
Using PCR, a significant percentage (28%) of cases of necrotising non-granulomatous lymphadenitis in this study could be attributed to M tuberculosis. PCR for identification of the organism can be extremely helpful in confirming a diagnosis of tuberculosis when Ziehl-Neelsen staining is negative.
Nopvichai
C
C
Department of Pathology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
Sanpavat
A
A
Sawatdee
R
R
Assanasen
T
T
Wacharapluesadee
S
S
Thorner
P S
PS
Shuangshoti
S
S
D000293:Adolescent; D000328:Adult; D001706:Biopsy; D004269:DNA, Bacterial / Q000302:isolation & purification; D005260:Female; D005557:Formaldehyde; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000302:isolation & purification*; D009336:Necrosis; D009504:Neutrophils / Q000473:pathology; D016612:Paraffin Embedding; D016133:Polymerase Chain Reaction / Q000379:methods; D012680:Sensitivity and Specificity; D014388:Tuberculosis, Lymph Node / Q000175:diagnosis* / Q000473:pathology; D055815:Young Adult
D004269:DNA, Bacterial; D005557:Formaldehyde