A patient with known small cell lung carcinoma develops progressive, symmetric hyperpigmentation of the intertriginous areas along with hypertrophic palmoplantar keratoderma (tripe palms). What is the paraneoplastic mediator most responsible?

• A Ectopic PTHrP causing hypercalcaemia
• B Ectopic ACTH causing Cushing's and hyperpigmentation
• C Anti-Hu paraneoplastic antibodies targeting keratinocytes
• D Tumour secreted EGF receptor ligands (TGF-alpha, amphiregulin) ✓

Explanation

Tripe palms (acquired palmoplantar keratoderma with rugose, ridged texture resembling tripe) is strongly associated with gastric and lung carcinomas and is paraneoplastic via secretion of EGF receptor ligands (TGF-alpha, amphiregulin) that drive epidermal hyperproliferation. When combined with acanthosis nigricans it is called the sign of Leser-Trélat is distinct — tripe palms operate through the same EGF-receptor pathway. Ectopic ACTH from SCLC causes Cushing's, not keratoderma.

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.