The patient was a 27-year-old Chinese woman who was a laboratory doctor in a hospital involved in the treatment of sputum samples from patients with TB. The patient had never received immunosuppressive treatment, was serologically negative for HIV and hepatitis, and had no family history of TB. She was admitted to a hospital following a 7-day history of hoarseness without fever, cough, expectoration, emaciation, sweating, sore throat, or other non-specific symptoms such as anorexia, fatigue, and muscle aches. The patient's chest computed tomography (CT) and routine blood chemistry results, erythrocyte sedimentation rate (ESR), and tumour markers were all normal. The results of the acid-fast stain test of sputum smear and mycobacterial identification on throat secretion by the polymerase chain reaction (PCR) were all negative. The laryngoscopy revealed laryngeal mucosa hyperaemia and milky hyperplastic lesion in the bilateral vocal cords (Figure 1a). Histological analysis of the biopsy specimen from the vocal cords revealed granulomas with inflammatory cell infiltration in the squamous epithelium and interstitial tissue (Figure 2a) and negative results of periodic acid-Schiff stain (PAS), acid-fast stain (Figure 2b), and Gomori methenamine silver stain (GMS).
We cut the biopsy vocal cords directly, digested the homogenised tissues with proteinase K, and prepared template deoxyribonucleic acid (DNA) for PCR amplification. The mycobacteria gene chips (Mycobacteria Identification Array Kit and Tuberculosis Drug Resistance Detection Array Kit, CapitalBio Corp., China) were used to identify the bacteria and resistance genes. The results showed that MTB was positive (Figure 3a), and the detection of resistance genes indicated that rifampin and isoniazid had a wild-type genotype (Figure 3b and c).
Consequently, the patient was diagnosed with laryngeal TB and was treated with an antibiotic regimen combining rifampicin (10 mg/kg/day), isoniazid (5 mg/kg/day), pyrazinamide (30 mg/kg/day), and ethambutol (20 mg/kg/day) for 3 months and subsequently rifampicin (10 mg/kg/day), isoniazid (5 mg/kg/day), and ethambutol (20 mg/kg/day) for 9 months. After 1 year of well-tolerated treatment, the patient recovered, and the hyperplastic lesion in the vocal cords completely disappeared under laryngoscopy (Figure 1b).
The authors received research approval from Institutional Medical Ethic Review Board.
Informed consent was obtained from the patient included in this study.