Primary Subglottic Laryngeal Tuberculosis Mimicking as Malignancy: A rare case Report

Abstract

Primary Laryngeal Tuberculosis is an uncommon clinical entity. Reported incidence of laryngeal tuberculosis is less than 1%. Secondary laryngeal TB is more common and is presumed to arise from spread of infected secretions from lungs to vocal cords. We report an unusual case of primary laryngeal TB of subglottic region in a 31 year female who presented with persistent throat irritation and hoarseness of voice since two months with mild respiratory discomfort and was diagnosed to have primary subglottic Tuberculosis.

We report this case owing to the rarity of disease, sometimes masquerading as malignancy.

Introduction

Primary Laryngeal tuberculosis is rare, and its diagnosis requires a high degree of clinical suspicion [1]. The presenting features are usually hoarseness or respiratory difficulty with other vague and nonspecific symptoms [2]. It may be misdiagnosed clinically as primary malignancy due to its ulceroproliferative appearance and nonspecific presentation [3]. Histopathological examination of tissue and biopsy are mandatory to establish a definitive diagnosis.

Case Report

A 31 year old female, immunocompetent, non diabetic presented with complaints of Hoarseness of voice since 3 months, mild respiratory difficulty and intermittent dry cough. There was no history of fever and weight loss. On general physical examination she was well oriented to time, place and person, well nourished with no lymphadenopathy or any other positive sign. Her haematological, chest X Ray and biochemical investigations were within normal limits.

Indirect laryngoscopy had shown an ulcerative lesion in left subglottic region below left True Vocal cord. MRI Neck was done to evaluate extent of lesion, showing subtle irregularities of left subglottic region (Fig. 1(a), Fig 1(b), Fig. 2(a), Fig 2(b)).

Fig. 1.

1(a) Laryngeal endoscopy showing ulcerative lesion in subglottic region below left true vocal cord. 1 (b) Follow up laryngeal endoscopy shows resolved lesion in subglottic region after 2 months of anti-tuberculous therapy.

Fig. 2.

(a, b) A well defined altered signal intensity of showing T1 hypointense and T2/STIR heterogenous of size measuring approx. 10*9*11 mm (AP*TR*CC) seen in left subglottic region, no evidence of diffusion restriction noted

MRI Neck

HRCT Chest study was normal. Direct laryngoscopy was performed and debulking of lesion was done with cold instruments and sent for histopathology. The pathologic examination revealed caseating granulomatous lesion, inflammation with epitheloid cells, and few giant cells with positive AFB on Ziehl-Neelsen staining suggestive of laryngeal tuberculosis.

She was immediately started on fixed dose regimen of anti tubercular therapy, with 4 Drugs ( Isoniazid, Rifampicin, Ethambutol And Pyrazinamide ) for 2 months. After two months of therapy, the patient improved symptomatically and is will receive isoniazid and rifampicin for next 4 months. Patient is under regular follow up and completely asymptomatic.

Discussion

Primary laryngeal tuberculosis is a rare clinical entity and is often caused by direct invasion of inhaled Mycobacterium tuberculosis bacilli [4]. Alcohol abuse and smoking constitute two known risk factors [5].

Laryngeal TB often presents with hoarseness of voice (80–100%) and odynophagia (50–67%). If left untreated, it may lead to severe dyspnoea and stridor due to laryngeal oedema and granulations [6, 7].

Agarwal study [8] reported majority of laryngeal TB present as ulceroproliferative lesions similar to current case scenario. The main differential diagnosis for laryngeal tuberculosis is carcinoma of the larynx, which may have a misleading clinical, endoscopic presentation [9, 10]. Falagas et al. [11] reported simultaneous presence of laryngeal malignancy and TB. The other diagnosis to be kept in mind are granulomatous lesions of the larynx like syphilis, sarcoidosis, Wegener’s granulomatosis, actinomycosis [12, 13].

Laryngeal sarcoidosis most commonly occurs in age group of range 20–40 years, most common involved site being Supraglottis. The lesions may appear edematous, granular, or even nodular. Wegener’s granulomatosis presents between 3rd -5th decade and involves glottis, subglottis and presents with hoarseness and subglottic stenosis. Laryngeal syphilis affects glottic region and presents with stridor and gummatous lesions on vocal cords [14]. Laryngeal actinomycosis involves supraglottis, glottic region and presents with dysphonia, ,dysphagia, stridor and nodular mass on vocal folds [13].

According to Shin et al., the findings of laryngeal tuberculosis may be categorized into four groups: (a) whitish ulcerative lesions (40.9%), (b) nonspecific inflammatory lesion (27.3%), (c) polypoid lesions(22.7%), and (d) ulcerofungative mass lesions(9.1%) [15]. The prevalence of laryngeal sites affected by tuberculosis are true vocal folds (50–70%), false cords (40–50%), and epiglottis, aryepiglottic folds, arytenoids, posterior commissure, and/or subglottis (10–15%) [16]. In the present case, Subglottis was involved.

Laryngeal tuberculosis can also cause posterior glottic stenosis, subglottic stenosis, and vocal cord paralysis due to cricoarytenoid joint or recurrent laryngeal nerve involvement if early treatment is not instituted [17].

ATT is treatment of choice for laryngeal tuberculosis with a fixed dose regimen in 2 phases; 1st is intensive phase treatment with 4 drugs and 2nd phase with 2 drugs [18]. The role of surgery is limited to diagnostic laryngoscopy and biopsy. Tracheostomy may be required in larger lesions obstructing the airway and causing stridor [19].

To conclude, with increased incidence of laryngeal tuberculosis, change in its clinical pattern and spread mechanism, increased prevalence of polypoidal or nonspecific changes in larynx, treating otolaryngologists and physicians should always be aware of the possibility of primary laryngeal tuberculosis.

Funding

The authors have no relevant financial or non financial interests to disclose

Declarations

Ethics Approval

Ethics Approval has been obtained from the ethics committee of Government Medical College, Patiala

Consent for Publication

Not applicable.

Conflict of Interest

Not applicable.