Gastric Cancer Presenting as a Thickened Neck Skin Plaque

What happened, in summary

A 60-year-old man sought care after 10 months of progressive skin thickening and darkening over the front of his neck. The area began as a small lesion and gradually expanded, but it caused no pain, itching, scaling, or discharge. Examination showed a firm, leather-like plaque measuring 10 × 8 cm across the front and sides of the neck. No other skin lesions or enlarged lymph nodes were found, and examination of the breasts, mouth, nose, and larynx was unremarkable.

Pathology showed signet ring cells containing mucin. The tumor was CK7 positive and negative for estrogen receptor, progesterone receptor, and GCDFP, helping rule out an occult breast primary. Endoscopy subsequently confirmed a gastric primary. The neck lesion represented carcinoma en cuirasse, a rare pattern in which metastatic cancer spreads through the skin and creates a thick, fixed plaque.

He was advised to undergo whole-body imaging and was referred to oncology, but he deferred further evaluation and treatment. The disease progressed quickly, and he died within 3 months of presentation. The neck skin change was the first sign of the gastric cancer and remained the only identified distant site.