Granulomatous lymphadenitis in Taiwan: Unraveling infantile peak and Bacillus Calmette-Gue´rin lymphadenitis

Abstract

Background: Granulomatous lymphadenitis, a histopathological diagnosis, often indicates infections, such as those caused by mycobacterial and fungal agents. Methods: We conducted an analysis of 1098 granulomatous lymphadenitis cases, examining age distribution, lymph node locations, and laterality. Molecular detection of Bacillus Calmette- Gue´rin (BCG) was performed on archived formalin-fixed paraffin-embedded tissue specimens. Results: Our analysis revealed a bimodal age distribution, notably with a minor peak in infants. These infantile cases predominantly featured axillary involvement, frequently occurring on the left side. Positive rates of BCG identification decreased with age: <1 year, 71%; 1e2 year, 33%; 2 e3 year, 13%; 3e4 year, 0%. Remarkably, only one of the 14 cases with molecularly confirmed BCG lymphadenitis had comments regarding BCG in the pathological report. Compared with patients born after 2016 (BCG at 5e8 months), those born before 2016 (BCG at birth) developed BCG lymphadenitis at a wider age range with right skewness (before 2016, 13 11 months [range, 3e33 months] vs. after 2016, 10 2 months [range, 8e13 months]). Four of the 14 BCGpositive cases had congenital heart disease. Seven patients received anti-tuberculosis drugs following surgical excision. No surgical complications were reported. Conclusions: BCG lymphadenitis constitutes a distinctive minor peak within the spectrum of granulomatous lymphadenitis in Taiwan. Pathologists should consider the possibility of BCG infection, especially in cases of infantile axillary, supraclavicular, neck lymphadenopathies on the left side. Moreover, BCG administration at 5e8 months may reduce delayed-onset BCG lymphadenitis.