ROUND CELL MALIGNANCIES OF OROFACIAL REGION—A DIAGNOSTIC PERPLEXITY

Background Round cell tumors encompass a wide spectrum of lesions. The separation and distinction of these lesions demand pathology expertise along with correlation of history, clinical site, imaging findings, and pertinent ancillary techniques like immunohistochemistry to ascertain a correct diagnosis. Discrimination between these entities is important because of difference in treatment and prognosis of these lesions. Objective The aim of this study was to discuss the perplexing cases of round cell malignancies encountered at our center, describe how the final diagnosis was ascertained, and devise an algorithm and diagnostic approach for these lesions. Methods Retrospective analysis of round cell malignancies reported in the Department of Oral Pathology and Microbiology, Centre for Dental Education and Research, All India Institute of Medical Sciences, Delhi, since January 2018 to January 2020 was done independently by 3 pathologists. A list of differential diagnoses was made in each of the cases with pertinent positive and negative immunohistochemical markers that paved the way for final diagnosis. Results The various round cell malignancies reported at our center were Ewing sarcoma, hematolymphoid malignancies, sinonasal undifferentiated carcinoma, and neuroendocrine carcinoma. A diagnostic approach was determined for all round cell lesions for correct diagnosis. Conclusions It is important to think appropriately regarding the origin of these round cell malignancies using a panel of immunohistochemical markers, keeping in mind clinical site, imaging findings, and histology using molecular studies as necessary to avoid diagnostic pitfalls.