A case of laryngeal tuberculosis observed with high-magnification endoscopy

We have few opportunities to observe patients with of laryngeal tuberculosis, because this disease only exists in less than 1% exist in all of pulmonary tuberculosis patients. However, laryngeal tuberculosis is important as a differential diagnosis with a superficial cancer. Currently the diagnosis of this rare condition will probably increase, as we have the opportunity when performing upper gastrointestinal endoscopy (UGS) to screen the pharyngeal and a laryngeal region at the same time. This case report concerns a laryngeal tuberculosis patient in whom a superficial laryngeal cancer was first suspected under a high-magnification endoscopic diagnosis. The patient was a man in his 50's with pharyngalgia. The doctor whom the patient consulted first discovered a superficial lesion in the epiglottis with a laryngeal fiberoscopy, and referred the patient to our hospital as having a suspicious malignant tumor. UGS findings revealed an obscure lesion which was reddish with white coat in the laryngeal side of the epiglottis. High-magnification endoscopy with narrow band imaging showed an atypical vessel pattern and granulated structure, the so-called frog spawn, without a normal vessel pattern. The finding was enough to remind us of malignant lesions. The histopathological findings from the biopsy, on the other hand, revealed only granulomatous changes with inflammatory cell infiltration and no neoplastic changes, and an acid-fast bacillus was discovered with Ziehl-Neelsen staining. The chest X-ray findings showed an infiltrative shadow with cavitation at both the superior lobe and apex of the lung. As a result, the patient was diagnosed as having pulmonary tuberculosis and secondary laryngeal tuberculosis. He underwent treatment with a combination of four antimicrobial agents in another hospital. We should diagnose laryngeal tuberculosis as soon as possible and prevent the spread of infection in the endoscopic unit, because of the high potential for infection. However, even UGS specialists might not be on top of this diagnosis because there is little experience of it. We should take the presence of laryngeal tuberculosis into consideration as a differential diagnosis of cancer, and confirm a diagnosis as soon as possible with whole body examinations including chest X-rays and bacteriological examinations.