Esophageal anthracosis: lesion mimicking malignant melanoma.

A case of anthracosis of the esophagus is reported. The patient was a previously healthy 69-year-old Japanese woman. A black and slightly elevated lesion was detected in her esophagus by upper gastroesophageal fiberoscopic examination. Endoscopically, the lesion looked like malignant melanoma. Thoracic esophagotomy was then performed. Histological examination revealed a pigmented lesion beneath the mucosal epithelial layer. The lesion consisted of an aggregation of histiocytes containing an abundance of tiny black pigments. A few mature lymphocytes and plasma cells were also evident in the periphery of the lesion. Histologically, these findings looked like lymph nodes in the pulmonary hilus; however, no lymph nodal structure was evident in the esophageal wall. Traction diverticula were also noted in the pigmented lesion. The patient has remained well without disease for 9 months since the surgery. Although anthracosis is a rare condition in the esophagus, the present case gave warning to pathologists and clinicians that it does indeed occur. Endoscopists and pathologists should differentiate anthracosis from malignant melanoma because the treatment and outcome are quite different for each.