Acanthosis nigricans (AN) in adults most commonly signals insulin resistance. However, 'malignant AN' (rapid onset, extensive, involving oral mucosa and palms) is most strongly associated with which internal malignancy?

• A Gastric adenocarcinoma ✓
• B Breast carcinoma
• C Renal cell carcinoma
• D Hepatocellular carcinoma

Explanation

Malignant acanthosis nigricans is most strongly associated with gastric adenocarcinoma (>50% of malignancy-associated AN cases). Other GI adenocarcinomas (colon, pancreas) follow. The pathomechanism involves tumour-derived TGF-alpha and other growth factors stimulating epidermal keratinocyte proliferation. Clinical clues distinguishing malignant from benign AN include rapid onset, involvement of oral mucosa, florid cutaneous papillomatosis, and tripe palms—which themselves strongly suggest lung or gastric carcinoma.

Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.