Clear Cell Sarcoma of Kidney : Cellular Pattern
Cellular Pattern: It consists either of 1) dense cellular sheets with little or no extracellular matrix or 2) discrete well-demarcated cellular nodules in a relatively hypocellular background. The cells have tightly packed, overlapping hyperchromatic nuclei. Mitotic activity is brisk. The vascular channels consist of thin, delicate capillaries. The cellular pattern closely resembles undifferentiated, small, round, blue cell tumor, and the differential diagnosis includes blastemal component of Wilms tumor and primitive neuroectodermal tumor.