Gastrointestinal stromal tumor of the rectum with activating mutation of c-kit: report of a case.

Abstract

Nonepithelial malignancies of the large bowel are rare. A new disease entity, gastrointestinal stromal tumors, has attracted attention among primary mesenchymal tumors of the gastrointestinal tract. Here we present a case of spindle-cell sarcoma of the rectum, lacking either smooth muscle cells or neural elements. Immunohistochemical findings and sequencing of the c-kit proto-oncogene diagnosed this tumor as a malignant gastrointestinal stromal tumor of the rectum.