Paediatric Oncology

A 2-month-old full-term male infant presented with worsening tachypnoea and a rapidly enlarging, smooth-topped, infiltrative, bronze-yellow nodule with overlying telangiectasias on the mid-sternum . CT scan was done. Immunohistochemical staining of biopsies from skin and pulmonary lesions demonstrated a highly proliferative histiocytosis which was positively immunoreactive, CD33 and factor XIIIa, weakly positive for CD68, and negative for CD1a, Langerin, CD34, CD20, CD3, CD43, SOX10, S100, C-KIT, lysozyme and myeloperoxidase. Whole body MRI and positron emission tomography (PET)/CT imaging confirmed that the extensive pulmonary and compressing spinal cord lesions were fluorodeoxyglucose (FDG)-avid, and further revealed an additional, metabolically active right meningeal/parietal parenchymal brain tumour and extensive mediastinal/abdominal lymphadenopathy. Fluorescence in situ hybridization (FISH) and DNA mutation sequencing of the histiocytomas revealed a translocated KIF5B-ALK fusion rearrangement.