Introduction
Tuberculosis of the esophagus is a rare condition, even in countries with a high incidence of tuberculosis (TB) [
1,
2], and studies estimate that it constitutes about 0.3% of gastrointestinal TB cases [
3]. Involvement of the gastrointestinal tract occurs through ingestion of infected sputum or hematogenous spread from primary pulmonary TB [
4]. Most cases of esophageal tuberculosis are secondary to direct extension from adjacent structures, such as mediastinal lymph nodes or pulmonary sites. Primary esophageal tuberculosis is even rarer [
5]. Esophagic involvement by tuberculosis usually affects the middle third of the esophagus at the carina level [
6]. The most common symptoms are dysphagia or retrosternal pain, but odynophagia and weight loss may also be present.
We present two case reports of esophageal involvement by Mycobacterium tuberculosis infection in immunocompetent persons.
Discussion
The diagnosis of esophageal tuberculosis is rare, hence there is a need for a high clinical suspicion. Tuberculosis rarely causes dysphagia, which occurs due to esophageal ulcers, tracheoesophageal fistula or extrinsic compression by the mediastinal or neck lymph nodes [
6,
7]. Tuberculosis can involve the esophagus as a primary infection or as a secondary manifestation of disease reactivation [
8]. Case one was clearly a case of secondary esophageal tuberculosis, as there was proven pulmonary tuberculosis by sputum mycobacteriological examination. However, in case two there was a past history of pleural effusion that resolved spontaneously, as well as a left juxtadiaphragmatic effusion that resolved with antituberculous therapy and was most likely caused by
M. tuberculosis. Given these facts, we cannot state for sure what was the primary focus of infection.
The most frequent symptom reported in esophageal tuberculosis is dysphagia, which occurs in about 90% of cases [
2,
9]. Other symptoms are odynophagia and retrosternal pain and the occurrence of symptoms such as fever, weight loss and anorexia [
2,
9] is also common. In our cases, dysphagia and epigastric pain were the cardinal symptoms.
Esophageal tuberculosis lesions can involve any segment of this organ, but is most often located in the middle third of the esophagus because of its proximity to the hilar and mediastinal lymph nodes surrounding the bifurcation of the trachea [
2,
9,
10]. In the cases presented, esophageal involvement was at the distal level. The most common macroscopic finding is an esophageal ulcer as observed in case one. However, hypertrophic growth as esophageal polyps may also be present as in case two [
5,
11]. Esophageal carcinoma is part of the differential diagnosis as was the case for both our patients. Diagnosis is usually made by upper gastrointestinal endoscopy with histology examination showing epithelioid granuloma with Langhans cells, central necrosis and acid-fast bacilli. This was the method that allowed the diagnosis in both cases. In secondary esophageal tuberculosis, diagnosis may be suggested by confirmation of tuberculosis involving adjacent structures [
5], which was not possible in case two, given the quick resolution of the abdominal effusion after starting antituberculous therapy.
Esophageal tuberculosis treatment is based on chemotherapy with four drugs (isoniazid, rifampicin, pyrazinamide and ethambutol) in a first phase lasting for two months, followed by a period of four to six months with two drugs (isoniazid and rifampicin). There are cases where treatment was successfully carried out with only three drugs for six months, excluding ethambutol [
12,
13]. Surgical treatment is reserved for complications such as esophageal, tracheoesophageal and aortoesophageal fistulas, the latter of which can lead to death by massive hematemesis [
14]. In both cases presented, six-months of antituberculous therapy was curative.
Esophageal strictures may result from external compression of the esophagus due to mediastinal or cervical lymph nodes as well as mediastinal fibrosis induced by tuberculosis. This condition results in long and narrow strictures that are difficult to dilate, and in which dilation may be associated with a higher rate of complications [
15].
Esophageal stenosis as a complication of esophageal tuberculosis is rare and there are few reports in the literature [
16,
17]. The stenosis in case one was probably the result of the healing process, but was severe and repeated esophageal dilatation was needed to maintain esophagogastric transit.
Conclusion
Although rare, esophageal tuberculosis must be kept in mind in patients with dysphagia, especially in countries with high prevalence of tuberculosis, even in immunocompetent patients. Active pulmonary tuberculosis should be ruled out, since early recognition of this infection is very important for public health. Treatment of esophageal tuberculosis with antituberculous drugs is curative, although complications may sometimes occur as in our case. Finally, esophageal cancer must be included in the differential diagnosis of the endoscopic findings in this situation.
Competing interests
The authors declare that they have no competing interests.
Authors' contributions
JG was a major contributor in writing and revising the manuscript. RD was involved in drafting the manuscript and revising it critically for important intellectual content. AC and AA analyzed and interpreted the patient data regarding mycobacteriological examination. All authors were responsible for the diagnosis, treatment and follow-up of the patients whose case reports were described. All authors read and approved the final manuscript.