%0 Journal Article %A Matthew Harwood %A Fiona E. Craig %A Ming Yang %T Rare Multisystem Histiocytic Sarcoma on 18F-FDG PET/CT %D 2021 %R 10.2967/jnmt.121.262247 %J Journal of Nuclear Medicine Technology %P 358-359 %V 49 %N 4 %X Histiocytic sarcoma (HS) is a rare malignancy with morphologic and immunophenotypic features indicating histiocytic differentiation. We present a case of HS with multisystem involvement, including an obstructing mass in the pancreatic head. 18F-FDG PET/CT is a valuable tool in staging this rare entity and in assessing the response to therapy. Knowing the diverse metastatic pattern of HS will help avoid imaging pitfalls on clinical 18F-FDG PET/CT scans. %U https://tech.snmjournals.org/content/jnmt/49/4/358.full.pdf