Esophageal anthracosis occurred after treatment of esophageal tuberculosis secondary to mediastinal tuberculous lymphadenitis: a rare case report

BACKGROUND: Anthracosis is a disease generally considered to be in the lungs resulting from exposure to industrial dust in the workplace. Esophageal anthracosis is a fairly rare phenomenon and shows a strong correlation with tuberculosis. Moreover, esophageal involvement in tuberculosis is also rare. We here present an extremely rare case in which follow-up gastroesophageal endoscopy revealed a mass with a sunken, black area in the center and raised ring-like pattern in the surrounding mucosa resembling malignant melanoma. Uncovering the patient’s tuberculosis history finally avoided a misdiagnosis or overtreatment. CASE PRESENTATION: A 67-year-old male patient was admitted to the hospital due to “repeated chest pain for 1 month”. Endoscopic ultrasonography and contrast-enhanced CT scans revealed a mass adjacent to the esophageal wall with unclear boundaries. Aspiration biopsy confirmed that esophageal tuberculosis was caused by nearby mediastinal tuberculous lymphadenitis. After a standard anti-tuberculosis treatment regimen, the patient achieved a favorable prognosis. The follow-up gastroesophageal endoscopy showed a sunken black lesion with elevated peripheral mucosa replacing the original tuberculous mass, which was thought to be anthracosis, a disease that rarely occurs in the esophagus. CONCLUSION: The diagnosis of tuberculosis should be taken into consideration when a submucosal mass appears in the middle part of the esophagus. Endoscopic ultrasonography can effectively contribute to a definite diagnosis. Moreover, this is the first case of esophageal anthracosis observed only 1 year after the treatment of tuberculosis, indicating esophageal anthracosis can be a short-term disease. The traction of the reduction of tubercular mediastinal lymph nodes after anti-tuberculosis treatment may create a circumstance for pigmentation or dust deposition.