Paraesophageal Anthracofibrosis Mimicking Metastatic Lymphadenopathy in Papillary Thyroid Cancer: a Case Report

ABSTRACT

Anthracofibrosis is luminal narrowing with a black anthracotic pigmentation on the bronchial mucosa. Extrapulmonary anthracofibrosis is very rare in head and neck region, and anthracofibrosis associated with adhesion to adjacent tissue can be misdiagnosed to malignancy. We report a rare case of a paraesophageal anthracofibrosis in a patient with advanced papillary thyroid cancer. The paraesophageal anthracofibrosis presented as a black colored hard mass with severe adhesion to the recurrent laryngeal nerve (RLN) during thyroid surgery, suspecting metastatic lymphadenopathy. With intraoperative frozen biopsy, unnecessary aggressive surgery with the injury of RLN can be avoided. Permanent histopathological examination of the mass revealed anthracofibrosis with strong positivity on Masson’s trichrome staining. This case highlights that anthracofibrosis should be included in differential diagnosis of paraesophageal masses, and frozen sectional biopsy can help in decision making during surgery. In addition, collagen might be involved in the adhesion of the anthracotic mass to the surrounding tissues.