Imatinib in Patients With Desmoid Tumor and Chondrosarcoma

Inclusion Criteria: * Histological diagnosis of DT or CDS. * Biomolecular or immunohistochemical evidence of Imatinib mesylate target (KIT, PDGFRα PDGFRβ activation and/or presence of PDGFα or PDGFβ) * Measurable or evaluable disease * Surgical resection of local disease unfeasible radically (or unaccepted by the patient, or amenable to become less demolitive, or easier, or likely more feasible, after cytoreduction) and/or metastatic disease. * ECOG Performance status 0, 1, 2 or 3 * Adequate bone marrow, liver and renal function * Female patients of child-bearing potential must have negative pregnancy test. * Male and female patients of reproductive potential must agree to employ an effective method of birth control throughout the study. * Written, voluntary, informed consent. Exclusion Criteria: * Previous treatment with any other investigational or not investigational agents within 28 days of first day of study drug dosing * Other primary malignancy with \<5 years clinically assessed disease-free interval, except basal cell skin cancer or cervical carcinoma in situ. * Grade III/IV cardiac problems as defined by the New York Heart Association Criteria * Severe and/or uncontrolled medical disease (i.e., uncontrolled diabetes, chronic renal disease, or active uncontrolled infection) * Known brain metastasis. * Known chronic liver disease (i.e., chronic active hepatitis, and cirrhosis). * Known diagnosis of human immunodeficiency virus (HIV) infection. * Previous radiotherapy to \>/=25% of the bone marrow or within the previous 2 months on target lesion. * Major surgery within 2 weeks prior to study entry. * Expected non-compliance to medical regimens (e.g. psychiatric diseases).