[Complete remission of an idiopathic hypereosinophilic syndrome while using imatinib].

HISTORY AND ADMISSION FINDINGS

A 47-year-old man with a hypereosinophilic syndrome (HES), which has been known for 20 years, was admitted to our department due to insufficient therapeutic response to hydroxyurea. In general, the patient felt well, but reported increasing neurological problems, such as ataxia, memory deficits and dysarthria.

INVESTIGATIONS

Bone marrow assessments corroborated the diagnosis of a HES. However, we were not able to detect the insertional deletion 4q12 with concomitant fusion of the FIP1L1 to the PDGFRA locus. Magnetic resonance imaging (MRI) indicated a granulomatous vasculitis, which was most likely due to the hematologic malignancy.

TREATMENT AND COURSE

: Despite negativity for the FIP1L1-PDGFRA fusion gene, therapy was started with the tyrosine kinase inhibitor Imatinib. This led to a rapid normalization of eosinophilic granulocytes in the peripheral blood as well as in the bone marrow. In addition, the neurologic symptoms substantially improved.

CONCLUSION

Imatinib provides a potent therapeutic option in FIP1L1-PDGFRA negative patients suffering from HES.