Esophageal acanthosis nigricans in association with adenocarcinoma from an unknown primary site.

A case of acanthosis nigricans with esophageal involvement is presented. Six months after the patient's initial examination, metastatic adenocarcinoma from an unknown primary site was discovered. This represents the ninth reported case of esophageal acanthosis nigricans; six of the eight previously described cases were in association with malignancy localized to the gastrointestinal tract. Esophageal acanthosis nigricans may be a more specific marker for associated malignancy than cutaneous or oral mucosal manifestations. If present, esophageal acanthosis nigricans may serve as an indication for an extensive search for occult malignancy.