MKI67 and neoplasm: Histologically, small cell carcinoma of the kidney is characterized by sheets of small round cells, high mitotic activity, and necrosis, with strong immunopositivity for neuroendocrine markers such as synaptophysin, CD56, and chromogranin [4,8]. A Ki-67 index of approximately 70%, as seen in our patient, is indicative of a highly proliferative tumor and correlates with poor prognosis [3].