OUTCOME AND FOLLOW UP
Tolerance of treatment was excellent, without any side effect. The patient has not experienced any rash flare since the start of treatment and pruritus has regressed. The dry cough and dyspnea have also disappeared, and the obstructive ventilatory disorder has improved on the respiratory function test. Biologically, the eosinophil count returned to normal (130/mm3), confirming the obtention of a complete hematologic remission (CHR), white blood cells were at 6590/mm3. The other blood cell lines were all normal. The eosinophil count remained definitely and continuously normal. In February 2022, because of the stability of the eosinophil count under Imatinib for 6 years, a check of the FIP1L1-PDGFRA transcript was performed and was found negative, confirming the obtention of a CMR. Therefore, Imatinib was discountinued provided that regular monitoring of the count blood cell and the FIP1L1-PDGFRA transcript were done every 3 months. Imatinib was stopped in February 2022. Three months later, the FIP1L1-PDGFRA transcript was still undetectable. In addition, the patient has no clinical symptoms: no cough, no rash, no pruritus, no tumor syndrome. The count blood cell shows a normal eosinophil count of 490/mm3. He did not show any signs of TKI withdrawal syndrome either. Nine months after Imatinib withdrawal, CMR is sustained.