[Myeloproliferative hypereosinophilic syndrome revealed by bipolar mucosal ulcerations]

Hypereosinophilic syndrome (HES) is defined as an eosinophil count equal to or greater than 1.5 G/L for more than 6 months with organ damage (heart, nervous system, lung, etc) after the exclusion of other common causes of eosinophilia. A myeloproliferative variant of HES with FIP1L1-PDGFRα fusion gene inducing constitutive activation of a tyrosine kinase receptor has been characterized. We report a case in which the diagnosis was revealed by mucosal erosions and ulcerations.

A 50-year-old man reported bipolar erosions. He presented with an erosion on the glans, an ulceration on the lower lip and mild dermographism. He had an eosinophil count of 7.5 G/L (n<0.7) and raised LDH at 520 IU/L (n<480). Screening for the usual causes of eosinophilia was negative. Histology of the labial ulceration showed a polymorphous inflammatory infiltrate containing eosinophils. A chest scan demonstrated a ground glass-like pulmonary infiltrate and broncho-alveolar lavage revealed eosinophilic alveolitis. The myelogram showed rich bone marrow with eosinophils. FIP1L1-PDGFRα fusion transcript was detected in the blood. Imatinib (Glivec(®)) was initiated and a favourable outcome was achieved within a few months and maintained after one year of treatment.

Cutaneous signs are frequent features of HES. They are polymorphous and include pruritis, erythematous rash and urticaria. Mucosal ulcerations are uncommon and appear more frequently with the myeloproliferative FIP1L1-PDGFRα-associated variant of HES. Early diagnosis allows the onset of a targeted treatment with imatinib that may prevent the apparition of organ damage.