Glucagonoma is a relatively rare pancreatic islet cell tumor. Historically, these tumors present a typical constellation of symptoms including diabetes, weight loss, anemia, necrolytic migratory erythematous rash, and propensity for thrombosis. This clinical presentation is described as the glucagonoma syndrome. The syndrome can be confirmed with the use of serum measurements of glucagon levels and immunohistochemical assay of the tumor. Variations from the classic syndrome have been described, and serum measurements of glucagon in patients with suspected islet cell tumors can identify subsets of patients with glucagonoma who do not exhibit the classic syndrome. In our case, the unusual presentation of glucagonoma included the previously unreported component of an intravascular venous extension of tumor.