Necrolytic Migratory Erythema is a sign of underlying cancer due to involvement of:-

Necrolytic Migratory Erythema Cutaneous reaction that occurs because of Hyperglucagonaemia. It is due to Glucagonoma, an a-cell tumour, which is in tail of the pancreas, and which secretes excessive amounts of proglucagon-like material. Other causes are: -Pancreatic insufficiency, -Intestinal causes of malabsorption, -Intestinal protein loss (eg: secondary to lymphatic disease--Waldmann's syndrome), -Hepatic cirrhosis, and -Aberrant glucagon- secreting tumours such as bronchial or nasopharyngeal carcinoma .