Cytodiagnosis of metastatic Ewing's sarcoma of orbital mass and its confirmation by demonstration of EWS/friend leukemia integration 1 fusion gene

The utility of fine needle aspiration cytology in orbital haematolymphoid neoplasms

BACKGROUND

Orbital hematolymphoid lesions are rare and usually encountered in elderly patients. Orbital lesions are not easy to biopsy: hence fine needle aspiration cytology (FNAC) can be a very good diagnostic modality for these lesions.

MATERIALS AND METHODS

Cases of orbital masses subjected to FNAC dating from 2013 to 2020 were retrieved from our archives. A total of 16 cases with biopsy confirmation were included. All clinical details, the type of procedure, details of the immunocytochemistry (ICC) performed on smear, follow-up biopsy, and their haematological work-up were analysed in detail.

RESULTS

Sixteen biopsy-confirmed cases had been diagnosed as orbital haematolymphoid lesions on cytomorphology and further categorised with ancillary studies including ICC. In twelve instances, the cytology impression was congruent with the histopathological diagnosis and eight of the sixteen cases (50%) proved to be primary orbital lymphoma. Four were secondary orbital lymphomas and the remaining four included one case each of plasmacytoma, myeloid sarcoma, Rosai-Dorfman disease and angiolymphoid hyperplasia with eosinophilia.

CONCLUSION

FNAC is a minimally invasive procedure for diagnosing most of the haematolymphoid orbital lesions and it has a rapid turnaround time. The accuracy of cytomorphology combined with ICC on smears/cell blocks can be as good as a biopsy for exact categorisation. Additionally, aspirate smears are preferred samples for cytogenetics compared to formalin-fixed tissue blocks, as molecular cytogenetics techniques are frequently employed for diagnostic, prognostic, and therapeutic purposes.

Cytodiagnosis of Extraskeletal Ewing's Sarcoma and its Confirmation by Fluorescence in situ Hybridization

Extraskeletal Ewing's sarcoma is an aggressive malignant small round cell tumour usually occuring in children and adolescents. It needs to be differentiated from other malignant small round cell tumours and immunohistochemistry plays a pivotal role in establishing the diagnosis. Fluorescence in situ hybridization or real time-polymerase chain reaction helps in confirming the diagnosis by demonstration of EWS-FLI1 translocation, which is found in approximately 85% of the cases. We report a case of extraskeletal Ewing's sarcoma in a10-year-old male, who presented with a right gluteal region mass. Fine needle aspiration and cell block preparation followed by a panel of immunohistochemical markers were performed. Immunohistochemistry for CD99 and FLI1 was positive. EWS-FLI1 translocation was confirmed by fluorescence in situ hybridization.