Bone metastasis of a gastrointestinal stromal tumor: A report of two cases.

Gastrointestinal stromal tumors (GISTs) are the most frequently diagnosed mesenchymal tumors of the GI tract. GISTs usually arise from the stomach, followed by the small intestine, rectum and other locations in the GI tract. The most common metastatic sites are the liver and peritoneum, whereas GISTs rarely metastasize to the bone. Although a small number of previous studies have described bone metastases originating from GISTs, the true prevalence is yet to be elucidated. The present study describes two cases of bone metastasis in patients with GISTs and reviews the relevant literature. Case one was of a 78-year-old male who presented with bone metastasis to the femoral neck five years after the resection of a GIST. The metastasis was completely resected and the patient remains alive nine years after the initial diagnosis of the GIST. Case 2 was of a 41-year-old male who presented with bone metastases to the ribs following resection of GISTs seven and 17 years earlier. The metastases were completely resected and the patient remains alive 17 years after the initial diagnosis. In total, only 10 cases of GISTs with metastases to the bone have been reported in the English literature. The possibility of bone metastases originating from a GIST should be considered during clinical follow-up, particularly in the presence of liver metastases. If feasible, bone metastases should be completely surgically excised.