Figures
Figure 1. Left renal mass. Non-contrast and contrast-enhanced axial CT of the abdomen shows a well-defined mass in the interpolar region of the left kidney. a) Non-contrast CT shows a small focus of calcification (arrow head) within the mass. b) Arterial phase image shows heterogenous and intense enhancement. c) Venous phase image shows relative washout with areas of necrosis (asterisk) within the mass.
Figure 2. Rectosigmoid mass. a) Contrast-enhanced axial CT in arterial phase shows a well-defined moderately enhancing mass involving the rectosigmoid region (curved arrow). b) Sagittal reformatted CT after rectal contrast shows the polypoidal mass (curved arrow) infiltrating the perirectal fat with an adjacent perirectal lymphadenopathy (straight arrow).
Figure 3. Colonoscopy shows an intraluminal polypoidal mass lesion (curved arrow) involving the rectosigmoid region.
Figure 4. Histological confirmation of the diagnosis of poorly differentiated neuroendocrine carcinoma of rectum. a) Photomicrograph of hematoxylin and eosin stained biopsy sample of the rectosigmoid mass shows small round blue cells arranged in zellballen pattern with nuclear molding. Vesicular nucleus with salt and pepper chromatin is also seen (× 200). b) Immunohistochemistry of the rectal mass shows tumor cells focally positive for synaptophysin, and c) chromogranin (× 200).
Figure 5. Histological confirmation of the diagnosis of renal cell carcinoma: clear cell type of the left kidney. a) Photomicrograph of hematoxylin and eosin stained section of the renal mass shows nests of clear cells with intervening thin fibrovascular septae (× 400). b) Photomicrograph of hematoxylin and eosin stained section of adjacent compressed normal kidney (× 100).