A case report of CIC‐rearranged undifferentiated small round cell sarcoma in the cerebrum

Abstract

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.

CIC‐DUX4 sarcoma diagnosed by fine‐needle aspiration cytology: A case report

“…Cytologic findings of CIC‐DUX4 sarcomas have been described rarely in literature. Ito et al reported a CIC‐DUX4 sarcoma in the cerebrum with cytologic features of round to ovoid nuclei with mild pleomorphism, finely granular chromatin and some with prominent nucleoli (Table ). Some nuclei were eccentrically placed with vacuolated cytoplasm.…”

Cytomorphological features and literature review of CIC‐DUX4‐positive sarcoma, confirmed by reverse transcription polymerase chain reaction in a paediatric patient

“…Despite being generally categorised as undifferentiated round‐cell sarcomas , there is a certain degree of cytomorphological heterogeneity within these tumours 11 . There are only a few reports of cytomorphological features of CIC‐DUX4‐ positive sarcomas on fine needle aspirates 12‐14 . We present cytomorphological features of a rare case of a CIC‐DUX4 fusion‐positive sarcoma, confirmed by reverse transcriptase (RT)‐polymerase chain reaction (PCR), in a paediatric patient.…”

“…11 There are only a few reports of cytomorphological features of CIC-DUX4-positive sarcomas on fine needle aspirates. [12][13][14] We present cytomorphological features of a rare case of a CIC-DUX4 fusion-positive sarcoma, confirmed by reverse transcriptase (RT)-polymerase chain reaction (PCR), in a paediatric patient.…”

“…as similarly observed by others. [12][13][14] Thereafter, the tumour was tested for WT1, calretinin and CCNB3 that act as surrogate markers for consideration and further triage of CIC-rearranged sarcomas and BCOR-CCNB3 positive sarcomas, respectively. 5,7,9 Despite WT1 immunopositivity, lack of AE1/AE3 and synaptophysin were helpful in ruling out a DSRCT.…”

“…Other surrogate markers reported in these tumours include p16 and D2-40. 12 Lately, ETV4 immunostaining has been reported as another useful marker in the diagnosis of CIC- features. 3,[6][7][9][10][12][13][14] In conclusion, the present report constitutes the fifth case of 18.…”