Morphometrical analysis of the spectrum of small round cell tumors in a tertiary care centre

Introduction: The term “small round-cell tumors” (SRCT) describes a group of highly aggressive malignant neoplasms composed of small, monotonous cells with high nucleocytoplasmic ratios. Microscopic tumor burden, pre and post therapy tumor necrosis quantification and mitotic index may help as an alternative method of assessing the prognosis in these patients. Aims: Morphometrical analysis of the spectrum of small round cell tumors over a period of five years and its role in grading the tumors with respect to microscopic tumor burden, tumor necrosis and mitoses. Materials and Methods: This study included 39 cases of small round cell tumors (19 NHL, 6 Ewings/PNET, 3 atypical carcinoid, 3 olfactory neuroblastoma, 2 cases each of rhabdomyosarcoma, wilms tumor, neuroblasoma and monophasic synovial sarcoma across all age groups. The study was confined to bone and soft tissues. The microscopic tumor burden and tumor necrosis was assessed using computer assisted morphometric analysis by digital processing. Concurrently the number of mitosis were studied and correlated. Results: Thirty nine cases of small round cell tumors were morphometrically analyzed using image pro-plus analysis soft ware 5.0. The mean of microscopic tumor burden / necrosis / mitoses were compared among the four commonly encountered small round cell tumors namely atypical carcinoid, non-Hodgkins lymphoma (NHL), olfactory neuroblastoma, Ewings/PNET using Kruskal-Wallis Test. The difference was significant with respect to necrosis (p=0.003) and mitoses (p=0.003). Similarly inter group comparison of mitoses and necrosis were done for atypical carcinoid, NHL, olfactory neuroblastoma and Ewings/PNET using Mann-Whitney U Test. Inter group comparison of necrosis showed that the mean tumor necrosis of Ewings/PNET was more when compared with NHL, atypical carcinoid and olfactory neuroblastoma, showing a significant p value of 0.002, 0.020 and 0.018 respectively. The mean mitotic figures of Ewings/PNET when compared with atypical carcinoid and olfactory neuroblastoma were statistically significant (p0.020 and 0.020 respectively). Similarly, mitotic figures of NHL were more when compared with atypical carcinoid and olfactory neuroblastoma (p0.006 and 0.006). Conclusion: The above results reveal that Ewings/PNET have relatively more tumor necrosis, mitosis compared to other SRCT. In the forthcoming years, it will be extremely useful to find out the reversal of these patterns as the tumors are subjected to chemotherapy and radiotherapy.