Metastatic skin cancer; a case with signet ring cell histology.

We report a 64-year-old Japanese man who developed metastatic skin cancer, in the form of 1-3 cm diameter dome-shaped tumours on his face and head. Histopathological examination demonstrated diastase-resistant periodic acid--Schiff and Alcian blue-positive signet ring cells, suggesting gastric carcinoma. Immunohistochemical staining showed that these cells were positive for carbohydrate antigen CA19-9.