AJH Educational Material Bone marrow cellular cannibalism by medulloblastoma Virginia Escamilla, 1 Emilio Franco-Mac  ıas, 2 Cristina Calder on-Cabrera, 1 Eloy Rivas, 3 Rosario M. Morales-Camacho, 1 Maria Teresa Vargas, 1 * Ricardo Bernal, 1 and Jos e A. P erez-Sim on 1 Cellular cannibalism consists on the internalization of a cell into another of the same lineage. Internalized cells can maintain unaltered form (emperipolesis), suffer from degenerative passive changes, or be digested when the receptor cell is phagocytic (phagocytosis). A six-year-old girl started with endocranial hypertension due to IV ventricle tumor complicated with obstructive hydrocephalus. Tumor resec- tion and placement of a ventriculoperitoneal shunt were accomplished. Histological diagnosis was established for large cell/anaplastic medullo- blastoma (Image 1, panel 1a,b), WHO grade IV, belonging to high risk no Wnt/SHH group, probably group 3, according to international consensus [1]. Image 1. Panel 1: Histological brain section. H&E stain, 4003 (a). The inset shows complex cannibalism (wrapping o cannibalism) (b). Panel 2: Bone marrow aspirate. MGG stain, 1,0003. Classical morphological features of cannibalism phenomenon in various stages: approximation (a); gradual penetration (b–e), and complete internalization (f). Panel 3: Bone marrow aspirate. MGG stain, 1,0003. One malignant cell is internalizing into another cell and this complex is engulfed by another cell (a–c). One cell internalizing into two cells at a the same time (d–e), and in other area, two cells were seen internalizing into one another (f). Panel 4: Bone marrow aspirate. MGG stain, 1,0003. Three erythrocytes are internalized by a malignant cell (a), two erithrocytes are internalized by one malignant cell, and this complex is internalized by another cell (b). Erythroblast internalization (c). 1 UGC de Hematolog  ıa, Hospital Universitario Virgen del Roc  ıo, Instituto de Biomedicina de Sevilla (IBIS)/CSIC/Universidad de Sevilla, Sevilla, Spain; 2 UGC de Neuro- ciencias, Hospital Universitario Virgen del Roc  ıo, Sevilla, Spain; 3 UGC de Anatom  ıa Patol ogica, Hospital Universitario Virgen del Roc  ıo, Sevilla, Spain Conflict of interest: Nothing to report. *Correspondence to: M. Teresa Vargas, UGC de Hematolog  ıa. Hospital Universitario Virgen del Roc  ıo, Instituto de Biomedicina de Sevilla (IBIS)/CSIC/Uni- versidad de Sevilla, Sevilla, Spain. E-mail: mtvargas@us.es Received for publication: 1 October 2014; Revised: 29 October 2014; Accepted: 30 October 2014 Am. J. Hematol. 90:466–467, 2015. Published online: 5 November 2014 in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/ajh.23892 V C 2014 Wiley Periodicals, Inc. 466 American Journal of Hematology, Vol. 90, No. 5, May 2015 doi:10.1002/ajh.23892 IMAGES IN HEMATOLOGY A JH A JH