{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,19]],"date-time":"2026-08-19T13:29:24Z","timestamp":1787146164290,"version":"build-2736575974"},"reference-count":32,"publisher":"Walter de Gruyter GmbH","license":[{"start":{"date-parts":[[2026,6,23]],"date-time":"2026-06-23T00:00:00Z","timestamp":1782172800000},"content-version":"unspecified","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/3.0"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Hypereosinophilia of undetermined significance (HE-US) represents a rare subtype of hypereosinophilia (HE) defined by a persistent absolute eosinophil count (AEC) \u2265 1500\/uL without an identifiable reactive or clonal cause, and importantly, without evidence of eosinophil-mediated end-organ damage. Long-term structured follow-up is essential due to its unpredictable outcome and the risk of transition into overt hypereosinophilic syndrome (HES) or occult malignancies.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Case presentation<\/jats:title>\n                    <jats:p>We report the case of a 47-year-old woman with severe, persistent blood hypereosinophilia (up to 13600\/uL) accompanied by chronic inconstant fixed erythematous-violaceous skin lesions. Extensive diagnostic evaluation for secondary, autoimmune, and clonal etiologies was negative, including fluorescence in situ hybridization (FISH) for FIP1L1-PDGFRA mutation. Bone marrow biopsy showed granulocytic hyperplasia with eosinophils &lt;10% and mild reticulin fibrosis (MF-1). Whole-body computed tomography (CT) revealed small generalized lymphadenopathy (\u2264 11mm) without parenchymal infiltration. The patient declined lymph-node biopsy. Although skin biopsy revealed eosinophilic infiltration, it was characterized as a non-specific reactive pattern without objective evidence of eosinophil-mediated cytotoxicity. The case was provisionally diagnosed as HE-US, acknowledging that lymphoproliferative disease could not be definitively excluded in the absence of the lymph-node biopsy. Intermittent systemic corticosteroids provide rapid hematologic response, but prompted immediate recurrence when tapered.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>The reported case underscores the diagnostic complexity and difficulties in managing hypereosinophilia of undetermined significance in clinical practice. While current evidence suggests a generally benign course, rare progression to hypereosinophilic syndrome or other malignancies requires structured long-term monitoring and individualized therapeutic decision-making.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.2478\/rjim-2026-0014","type":"journal-article","created":{"date-parts":[[2026,6,23]],"date-time":"2026-06-23T19:03:16Z","timestamp":1782241396000},"source":"Crossref","is-referenced-by-count":0,"title":["Severe Persistent Hypereosinophilia of Undetermined Significance: Diagnostic Challenges in Clinical Practice and Two-Year Follow-Up"],"prefix":"10.2478","author":[{"given":"Polliana Mihaela","family":"Leru","sequence":"first","affiliation":[{"name":"Carol Davila University of Medicine and Pharmacy, Department 5 , Bucharest , Romania"},{"name":"Colentina Clinical Hospital , Allergology Research Department , Bucharest , Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vlad Florin","family":"Anton","sequence":"additional","affiliation":[{"name":"Colentina Clinical Hospital , Allergology Research Department , Bucharest , Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Daniela Georgeta","family":"Georgescu","sequence":"additional","affiliation":[{"name":"Carol Davila University of Medicine and Pharmacy, Department 8 , Bucharest , Romania"},{"name":"Colentina Clinical Hospital , Hematology Department , Bucharest , Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"374","published-online":{"date-parts":[[2026,6,23]]},"reference":[{"key":"2026081913080348455_j_rjim-2026-0014_ref_001","doi-asserted-by":"crossref","unstructured":"AOKI A, HIRAHARA K, KIUCHI M, NAKAYAMA T. Eosinophils: Cells known for over 140 years with broad and new functions. Allergol Int. 2020;69:3\u201310.","DOI":"10.1016\/j.alit.2020.09.002"},{"key":"2026081913080348455_j_rjim-2026-0014_ref_002","doi-asserted-by":"crossref","unstructured":"VALENT P. Pathogenesis, classification, and therapy of eosinophilia and eosinophil disorders. Blood Rev. 2009;23(4):157\u2013165.","DOI":"10.1016\/j.blre.2009.01.001"},{"key":"2026081913080348455_j_rjim-2026-0014_ref_003","doi-asserted-by":"crossref","unstructured":"VALENT P, KLION AD, ROSENWASSER LJ, AROCK M, BOCHNER BS, BUTTERFIELD JH, et al. ICON: Eosinophil disorders. World Allergy Organ J. 2012;5(12):174\u2013181.","DOI":"10.1097\/WOX.0b013e31827f4192"},{"key":"2026081913080348455_j_rjim-2026-0014_ref_004","doi-asserted-by":"crossref","unstructured":"SUNADOME H, SATO S, MATSUMOTO H, MURASE K, KAWAGUCHI T, TABARA Y, et al. 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