Review Question - QID 107645

A non-diabetic patient presenting with acanthosis nigricans, along with gastric complaints and weight loss is most likely suffering from gastric adenocarcinoma. Although his obesity is a possible cause of the hyperpigmentation, the recent discovery on his neck along with acute onset of anorexia points toward an underlying malignant process.

Acanthosis nigricans is more frequently associated with diabetes, hyperthyroidism, and Cushing's syndrome. It is benign in nature and is often described as velvety thickening of the neck or axillary skin.

Stulberg et al. summarizes some of the most common skin hyperpigmentation disorders. As stated earlier, acathosis nigricans is most often due to diseases causing hyperinsulinemia but is also seen in gastrointestinal tumors. Although benign, precautions must be taken if the hyperpigmentation is hard to differentiate from characteristics of melanoma.

Lee et al. report on a case in which an acral type acanthosis nigricans is found in a patient with gastric adenocarcinoma. Acanthosis nigricans in gastric adenocarcinoma is most commonly reported in the flexural areas and very rarely in the acral areas of the body.

Incorrect Answers:
Answer 1: Hyperthyroidism sometimes results in acanthosis nigricans; however, hypothyroidism would be much more likely in the obese patient.
Answer 3: Acanthosis nigricans is seen in diabetes mellitus, not insipidus.
Answer 4: Although often seen in diabetics, this diagnosis has been ruled out in the patient described.
Answer 5: Barrett’s esophagus is an abnormal change in distal esophageal squamous cells into columnar cells. It is due to chronic reflux-related acid exposure.