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).