Abstract
clinicopathologic data of 39 cases, including 37 cases with confirmed ALK rearrangements. The clinical spectrum comprised distinct clinical phenotypic groups: infants with multisystemic disease with liver and hematopoietic involvement, as originally described (Group 1A: 6/39), other patients with multisystemic disease (Group 1B: 10/39), and patients with single-system disease (Group 2: 23/39). Nineteen patients of the entire cohort (49%) had neurologic involvement (7 and 12 from Groups 1B and 2, respectively).
Histology included classic xanthogranuloma features in almost one-third of cases, whereas the majority displayed a more densely cellular, monomorphic appearance without lipidized histiocytes but sometimes more spindled or epithelioid morphology. Neoplastic histiocytes were positive for macrophage markers and often conferred strong expression of phosphorylated extracellular signal-regulated kinase, confirming MAPK pathway activation. KIF5B-ALK fusions were detected in 27 patients, whereas CLTC-ALK, TPM3-ALK, TFG-ALK, EML4-ALK, and DCTN1-ALK fusions were identified in single cases. Robust and durable responses were observed in 11/11 patients treated with ALK inhibition, 10 with neurologic involvement. This study presents the existing clinicopathologic and
molecular landscape of ALK-positive histiocytosis and provides guidance for the clinical management of this emerging histiocytic entity.
Original language | English |
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Article number | PMID: 34727172 |
Pages (from-to) | 256-280 |
Number of pages | 25 |
Journal | Blood |
Volume | 139 |
Issue number | 2 |
DOIs | |
Publication status | Published - 13 Jan 2022 |
Bibliographical note
Funding Information:P.G.K. received a grant from Leiden University Medical Center. A.G.S.v.H. is supported by Stichting 1000 kaarsjes voor Juultje. E.L.D. is supported by the National Institutes of Health/National Cancer Institute Core Grant (P30 CA008748), National Cancer Institute (R37 CA259260-01), the Frame Fund, Applebaum Foundation, and Joy Family West Foundation. J.-F.E. is supported by the Programme de Recherche Translationnelle sur le Cancer from the French National Cancer Institute (PRT-K19-143).
Publisher Copyright:
© 2022 American Society of Hematology