ALK-positive histiocytosis is a rare subtype of histiocytic neoplasm first described in 2008 in 3 infants with multisystemic disease involving the liver and hematopoietic system. This entity has subsequently been documented in case reports and series to occupy a wider clinicopathologic spectrum with recurrent KIF5B-ALK fusions. The full clinicopathologic and molecular spectra of ALK-positive histiocytosis remain, however, poorly characterized. Here, we describe the largest study of ALK-positive histiocytosis to date, with detailed 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 involv..... READ ARTICLE
Blood DOI:10.1182/blood.2021013338
Authors: Paul G. Kemps, Jennifer Picarsic, Benjamin H. Durham, Zofia Hélias-Rodzewicz, Laura Hiemcke-Jiwa, Cor van den Bos, Marianne D. van de Wetering, Carel J. M. van Noesel, Jan A. M. van Laar, Robert M. Verdijk, Uta E. Flucke, Pancras C. W. Hogendoorn, F. J. Sherida H. Woei-A-Jin, Raf Sciot, Andreas Beilken, Friedrich Feuerhake, Martin Ebinger, Robert Möhle, Falko Fend, Antje Bornemann, Verena Wiegering, Karen Ernestus, Tina Méry, Olga Gryniewicz-Kwiatkowska, Bozenna Dembowska-Baginska, Dmitry A. Evseev, Vsevolod Potapenko, Vadim V. Baykov, Stefania Gaspari, Sabrina Rossi, Marco Gessi, Gianpiero Tamburrini, Sébastien Héritier, Jean Donadieu, Jacinthe Bonneau-Lagacherie, Claire Lamaison, Laure Farnault, Sylvie Fraitag, Marie-Laure Jullié, Julien Haroche, Matthew Collin, Jackie Allotey, Majid Madni, Kerry Turner, Susan Picton, Pasquale M. Barbaro, Alysa Poulin, Ingrid S. Tam, Dina El Demellawy, Brianna Empringham, James A. Whitlock, Aditya Raghunathan, Amy A. Swanson, Mariko Suchi, Jon M. Brandt, Nabeel R. Yaseen, Joanna L. Weinstein, Irem Eldem, Bryan A. Sisk, Vaishnavi Sridhar, Mandy Atkinson, Lucas R. Massoth, Jason L. Hornick, Sanda Alexandrescu, Kee Kiat Yeo, Kseniya Petrova-Drus, Stephen Z. Peeke, Laura S. Muñoz-Arcos, Daniel G. Leino, David D. Grier, Robert Lorsbach, Somak Roy, Ashish R. Kumar, Shipra Garg, Nishant Tiwari, Kristian T. Schafernak, Michael M. Henry, Astrid G. S. van Halteren, Oussama Abla, Eli L. Diamond, Jean-François Emile