Primary pharyngeal tuberculosis presenting as a submucosal tumour

Abstract

We describe a rare case of primary pharyngeal tuberculosis without pulmonary involvement in which the lesion was thought to be a submucosal tumour with overlying intact mucosa. A 58-year-old male attended the outpatient ward due to a globus sensation in the throat of 2-month duration. A swelling of the posterior oropharyngeal wall was found. The lesion was thought to be a submucosal tumour on computed tomography and magnetic resonance imaging. Primary pharyngeal tuberculosis was confirmed by histopathological examination and polymerase chain reaction (PCR) analysis. The patient underwent 26 weeks of treatment with anti-tuberculous agents. He has been followed up for 12 months without any signs of disease recurrence.

Primary pharyngeal tuberculosis is a rare disease that usually occurs secondary to active pulmonary tuberculosis. Although tuberculosis infection was common in the 1930s, the average incidence of tuberculosis infection in the nose, mouth, and pharynx at that time was only 0.66%. Most cases of pharyngeal tuberculosis have presented with various mucosal states: ulceration, granuloma formation, lipoid lesions, and coated with discharge or blood. To date, few reports have addressed primary pharyngeal tuberculosis in the submucosal space with an overlying normal mucosal barrier. A case of primary pharyngeal tuberculosis without pulmonary involvement in which the lesion was thought to be a submucosal tumour with overlying intact mucosa is presented herein.

Case report

A 58-year-old male attended the outpatient ward due to a globus sensation in the throat of 2-month duration. He did not report dyspnoea, anorexia, cough, fever, chills, halitosis, rhinorrhea, sputum, pharyngeal pruritus, or hemoptysis. There was no past history of tuberculosis infection or surgery, and he had not been in contact with infected people. He did not smoke or drink alcohol.

On physical examination, he was of a slim build and had a non-anaemic appearance. There was no palpable lymph node and no sign of infection or fistula in the head and neck. Chest examination revealed no abnormal breathing sounds or radiological alterations. On flexible nasopharyngoscopic examination, the pharynx showed a swelling of the right posterior oropharyngeal wall measuring about 2 cm × 3 cm. Serum electrolytes and the results of kidney and liver function tests were within the normal range. A computed tomography (CT) scan showed a low-attenuation lesion of 3 cm × 4 cm with rim enhancement and postero-inferior calcification on the right side of the oropharyngeal wall ( Fig. 1 ). Magnetic resonance imaging (MRI) indicated a homogeneous lesion with high signal intensity in T2-weighted images and low signal intensity with peripheral rim enhancement in T1-weighted images.

Fig. 1
Axial enhanced neck CT image showing a low-attenuation lesion with partial rim enhancement (arrow) and posterior calcification on the right side of the pharyngeal wall (dotted circle).

The lesion was thought to be a submucosal tumour, and complete excision via the intraoral approach was planned. However, adhesion to the pharyngeal mucosa and visceral fascia prevented an en bloc excision, so a piecemeal excision was performed. Gross inspection of the surgical specimen revealed a well-defined submucosal mass filled with cheese-like calcified material. Histopathological examination revealed chronic granulomatous inflammation with caseous necrosis and Langhans giant cells surrounded by lymphocytes ( Fig. 2 a) . The collected tissue was positive for Mycobacterium tuberculosis DNA by polymerase chain reaction (PCR) analysis using a commercial M. tuberculosis and non-tuberculous mycobacteria (MTB and NTM) PCR kit (BioSewoom Inc., Seoul, Korea) ( Fig. 2 b). Ziehl–Neelsen staining did not show any acid-fast bacilli, and M. tuberculosis was not cultured from the sputum. Based on these results, a diagnosis of primary pharyngeal tuberculosis without pulmonary tuberculosis was made.

Fig. 2
(a) Light microscopy findings showing caseous necrosis (circle), epithelioid cell granuloma (dotted circle), and Langhans giant cells surrounded by lymphocytes (arrow) (original magnification 200×, haematoxylin and eosin stain). (b) PCR amplification of 181-bp and 242-bp regions of Mycobacterium tuberculosis DNA: lane M, DNA ladder; lane 1, patient sample; lane 2, positive control; lane 3, negative control.

Treatment was started with an oral regimen consisting of four anti-tuberculous agents for 10 weeks (isoniazid 300 mg, rifampicin 600 mg, ethambutol 800 mg, and pyrazinamide 1000 mg), after which treatment was continued with an oral regimen of three anti-tuberculous agents for 16 weeks (as above, but without pyrazinamide). After 26 weeks of treatment, the patient was asymptomatic. He has been followed up for 12 months without any signs of disease recurrence.

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Jan 19, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Primary pharyngeal tuberculosis presenting as a submucosal tumour
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