Prakasit Sa-Ngaimwibool, Puenpon Lukket, Yaowalux Chamgramol, Chawalit Pairojkul, Sakda Waraasawapati
Department of Pathology, Faculty of Medicine, Khon Kaen University
Primary renal neuroendocrine tumor or primary renal carcinoid tumor is a very rare primary tumor of the
kidney. This tumor appears to be associated with horseshoe kidney and the most common clinical features
being abdominal pain or hematuria. Here, we report on the case of 63-yearold Thai female who presented
with a mass on the right kidney when she got an annual check-up. The histomorphology revealed the tumor
arrangement in a tightly packed cord and trabecular pattern with monotonous round to oval nuclei with stripped
chromatin and fi nely granular cytoplasm. The immunohistochemical profi le showed positive reactivity to
synaptophysin, renal cell carcinoma marker (RCC-Ma) and CD56, but negative reactivity to WT-1,
chromogranin A and CD10. This case showed typical features of well-differentiated neuroendocrine tumor
similar to other organs. Interestingly, this tumor revealed positive reactivity to RCC-Ma. It might be suggested
that the tumor is possibly related to renal proximal tubule even with the negative reactivity to CD10. Further
study should be performed to classify this tumor.