Gastrointestinal stromal tumor with primary resistance to imatinib and extensive bone metastases.

Gastrointestinal stromal tumors (GISTs) are the most common nonepithelial tumors of gastrointestinal tract characterized by mutations activating c-KIT or platelet-derived growth factor receptor alpha. GISTs frequently metastasize to liver and peritoneum, but rarely to the bones. Imatinib, a tyrosine kinase inhibitor, has revolutionized the treatment of advanced and metastasized GISTs by both slowing down the disease progression and prolonging the survival. Occasionally, patients with GISTs can develop primary or secondary resistance to imatinib monotherapy. We are presenting an interesting case of metastatic GISTs with extensive bone lesions and primary resistance to imatinib. Efforts to identify bone metastases using appropriate imaging modalities are highly recommended in patients diagnosed with GISTs. Also, alternate strategies to overcome the emerging resistance with single agent imatinib chemotherapy are warranted. (C) 2011 Lippincott Williams & Wilkins, Inc.