A case report of CIC-rearranged undifferentiated small round cell sarcoma in the cerebrum.
CIC-rearranged undifferentiated small round cell sarcoma (CIC-rearranged USRCS) is a recently established type of Ewing-like small round cell sarcomas, characterized by CIC gene rearrangement, most commonly CIC-DUX4 fusion. This report presents the second case of CIC-rearranged USRCS arising primarily in the cerebrum. A 64-year-old otherwise healthy woman presented with a 1 × 1 cm sized hemorrhagic subcortical tumor in the left temporo-parietal lobe. The tumor repeatedly recurred, and the patient underwent three surgeries, chemotherapy with doxorubicin and ifosfamide, and radiotherapy, as well as gamma knife surgery. Systemic examination revealed no other extracranial masses. Imprint cytology revealed small to moderate-sized round-to-ovoid tumor cells with mild pleomorphism and variations in size and shape. The nuclei contained finely granular chromatin, and some had easily-recognizable nucleoli. The tumor exhibited a mainly cytoplasmic pattern of CD99 immunostaining, rather than a diffuse membranous pattern. The tumor also exhibited diffuse positivity for calretinin and p16, as well as partial positivity for WT1 (nuclear and cytoplasmic staining pattern) and D2-40. FISH assessment showed CIC split signals. In conclusion, CIC-rearranged USRCSs can occur primarily in the cerebrum. It would be impossible to diagnose them through cytology alone, but cytology would be useful to rule out other small round cell brain tumors including gliomas, lymphomas, carcinomas, and germinoma. Immunohistochemical analysis including tests for CD99, calretinin, and WT1 would help to suggest CIC-rearranged USRCSs and distinguish them from Ewing sarcomas. Additionally, immunohistochemistry for p16 might be useful in the diagnosis. Diagn. Cytopathol. 2016;44:828-832. © 2016 Wiley Periodicals, Inc.
Department of Diagnostic Pathology, Kainan Hospital, 396 Minamihonden, Maegasu-Cho, Yatomi, Aichi, 498-8502, Japan.
Mayumi
M
Ito
Department of Diagnostic Pathology, Kainan Hospital, 396 Minamihonden, Maegasu-Cho, Yatomi, Aichi, 498-8502, Japan.
Misawo
M
Ishikawa
Department of Diagnostic Pathology, Kainan Hospital, 396 Minamihonden, Maegasu-Cho, Yatomi, Aichi, 498-8502, Japan.
Masateru
M
Kitajima
Department of Diagnostic Pathology, Kainan Hospital, 396 Minamihonden, Maegasu-Cho, Yatomi, Aichi, 498-8502, Japan.
Jun
J
Narita
Department of Diagnostic Pathology, Kainan Hospital, 396 Minamihonden, Maegasu-Cho, Yatomi, Aichi, 498-8502, Japan.
Shinya
S
Hattori
Department of Neurosurgery, Kainan Hospital, 396 Minamihonden, Maegasu-Cho, Yatomi, Aichi, 498-8502, Japan.
Otone
O
Endo
Department of Diagnostic Pathology, Kainan Hospital, 396 Minamihonden, Maegasu-Cho, Yatomi, Aichi, 498-8502, Japan. vapour-trail@nifty.com.
Keisuke
K
Goto
D000071443:12E7 Antigen / Q000235:genetics / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D054022:Cerebrum / Q000000981:diagnostic imaging / Q000473:pathology*; D019941:Cyclin-Dependent Kinase Inhibitor p16; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D015514:Oncogene Proteins, Fusion / Q000235:genetics / Q000378:metabolism*; D012512:Sarcoma, Ewing / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D018228:Sarcoma, Small Cell / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*
D000071443:12E7 Antigen; D014408:Biomarkers, Tumor; C000614131:CDKN2A protein, human; C574694:CIC-DUX4 fusion protein, human; D019941:Cyclin-Dependent Kinase Inhibitor p16; D009363:Neoplasm Proteins; D015514:Oncogene Proteins, Fusion
CIC; brain; cerebrum; cytology; sarcoma