Intimal sarcoma is a rare disease with a poor prognosis. We herein report the case of a 71-year-old man with intimal sarcoma of the pulmonary artery treated with pazopanib. The tumor showed regression after 1 month of treatment. Hand-foot syndrome led to cessation of pazopanib, which triggered a disease flare. Pazopanib should be considered in patients with intimal sarcoma of the pulmonary artery that is unresectable or recurrent after surgery or cytotoxic chemotherapy. We must be careful about drug cessation, as it can lead to a disease flare.