Diagnosis of nontuberculous mycobacterial lymphadenitis: the role of fine-needle aspiration.

Nontuberculous mycobacterial lymphadenitis often presents a diagnostic challenge. This study aimed to evaluate the role of fine-needle aspiration cytology in the diagnosis of nontuberculous mycobacterial lymphadenitis in children. We conducted a retrospective review of fine-needle aspiration cytology performed in patients < 17 year-old with subacute lymphadenitis from 2003 to 2016 in a tertiary hospital in Spain. Confirmed nontuberculous mycobacterial lymphadenitis (isolation of nontuberculous mycobacterial in culture from fine-needle aspiration cytology or biopsy samples) and probable nontuberculous mycobacterial lymphadenitis ("granulomatous inflammation" in cytopathologic examinations from fine-needle aspiration cytology or biopsy and clinical-epidemiological history compatible with nontuberculous mycobacterial) were selected. Forty-one patients with nontuberculous mycobacterial lymphadenitis were included: 14 confirmed and 27 probable. Fine-needle aspiration cytology was done in all of them. For 34 patients with excised lymphadenopathy, cytopathology from fine-needle aspiration cytology was concordant with biopsy in 100% cases. Culture results were available from 78.0% (32/41) of patients with fine-needle aspiration cytology and from 85.3% (29/34) with excisional biopsy. Among 22 patients with microbiological results from fine-needle aspiration cytology and biopsy, fine-needle aspiration cytology allowed advanced results in concordance with biopsy or with positive isolation not found in biopsy in 90.1% (20/22) of patients. Sensitivity of nontuberculous mycobacterial cultures obtained by fine-needle aspiration cytology compared to biopsy was 45.5% vs. 36.4% (p = 0.07). Two patients with previous skin alterations presented fistulas after fine-needle aspiration cytology (4.9%); no other complications were described.Conclusion: Fine-needle aspiration cytology provides quick cytopathologic information and is an accurate and safe technique for the diagnosis of nontuberculous mycobacterial lymphadenitis, especially in cases with challenging work-up. What is Known: • Nontuberculous mycobacterial (NTM) infection is an important cause of subacute lymphadenitis in children. • Fine-needle aspiration cytology (FNAC) is an available technique for the diagnosis of lymphadenitis of unknown etiology. What is New: • FNAC is an accurate and safe technique for the diagnosis of NTM lymphadenitis in children. • FNAC can provide reliable samples for cytopathological studies and even a better sensitivity for microbiological culture than excisional biopsy in the study of suspected NTM lymphadenitis.