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Lymphocytic Variant of Hypereosinophilic Syndrome: diagnostic features of a rare entity
Author(s) -
SHAHAB ASIF SAIYED,
ZULFIQAR MUHAMMAD IMRAN
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.1002.23
Subject(s) - hypereosinophilic syndrome , eosinophilia , medicine , pathology , leukocytosis , myelofibrosis , essential thrombocythemia , population , immunology , bone marrow , polycythemia vera , environmental health
Hypereosinophilic syndrome (HES) includes a spectrum of diseases with eosinophilia and tissue damage. Two idiopathic causes of HES are the myeloproliferative variant (M‐HES)and the lymphocytic variant (L‐HES). L‐HES is a rare entity. It is characterized by clonal population of phenotypically abnormal T‐ lymphocytes. Clinical manifestations vary but cutaneous involvement is common. In this case we report a patient diagnosed with L‐HES with no clinical symptoms on presentation. A 56 year old male was initially being evaluated for leukocytosis with a differential showing 33% eosinophilia. Physical exam was unremarkable. The patient had an extensive workup to rule out secondary causes. Bone marrow biopsy revealed cellular marrow with eosinophilia (10% of cellularity). No evidence of myeloproliferative disorders. JAK2 mutation was negative as well as FISH for bcl‐abr gene and PDGFRA gene. Flow cytometry revealed an unusual population of CD4+, CD2+, CD3‐, and CD8‐ T‐lymphocytes. HES is an extremely heterogeneous disorder. Diagnostic criteria includes persistent eosinophilia of 1.5 × 10 9 eosinophils/L of blood, lack of evidence for secondary causes and presumptive signs of organ involvement. The L‐HES is an uncommon variant. Patients usually present with dermatologic manifestations. GI symptoms and obstructive lung disease are also common. Endomyocardial fibrosis and myelofibrosis are rarely seen. Cytokine IL‐5 also plays a role in pathogenesis. The most prevalent T cell clone associated with LHES seems to be the CD3‐CD4+ clone. L‐HES has a much better prognosis than M‐HES but patients with the CD3‐CD4+ clone can progress to T cell lymphoma. Despite the relatively low mortality in patients with LHES, morbidity is significant. L‐HES is steroid responsive while M‐HES is not. It is crucial to differentiate between the variants because of the vastly different treatment regimens and thus disease course.