PMC3882929_01
Radiologic imaging and gross photograph of tubulocystic renal cell carcinoma. Cystic lesions without contrast enhancement within the left (A) and right kidney (B). Sharply-demarcated cystic lesions of varying sizes with involvement of both cortex and medulla, are present in both the left (C) and right (D) kidneys. Black calculi were present in the renal pelvis bilaterally.
rt-2013-4-e57-g001.jpg
PMC3882929_01_rt-2013-4-e57-g001.jpg
fig001
After an additional 7 months (18 months after presentation), a repeat CT showed bilateral and multiple enhancing lesions: a 2.6x2.3 cm lesion and a 1.3x1.6 cm lesion in the left mid-kidney, a 1.8x1.7 lesion in the right upper pole, and a 1.5x1.6 cm lesion in the right midkidney (Figure 1A, B). On cut section, there were multifocal unencapsulated sharply demarcated gray spongy cystic lesions ranging from 0.3 to 2.5 cm in diameter in renal cortex and renal medulla (Figure 1C, D). Numerous black multifaceted calculi ranging from 0.1 to 0.2 cm in greatest dimension were present within both renal pelvises (Figure 1C, D).
Representative histologic features of tubulocystic renal cell carcinoma. Tubulocystic RCC is composed of tubules and cysts of varying size. (A) Two adjacent foci of tubulocystic RCC in the renal cortex and medulla of the left kidney (20x). (B) The cysts contain clear serous fluid (40x). (C) and (D) flat to cuboidal tumor cells with abundant eosinophilic cytoplasm line the tubules and cysts (100x). (D) The tumor cells have occasional prominent nucleoli (100x).
rt-2013-4-e57-g002.jpg
PMC3882929_01_rt-2013-4-e57-g002.jpg
fig002
On microscopic examination, the cystic lesions were composed of tightly packed tubules and cysts separated by bland fibrous stroma (Figure 2A-D). The cells had large round to oval nuclei (Fuhrman grade 2 to 3), prominent nucleoli, and abundant eosinophilic cytoplasm (Figure 2C, D).
Characteristic immunohistochemical features of tubulocystic renal cell carcinoma. (A) Diffuse strong immunoreactivity for AMACR (100x), (B) CK8/18 (40x; Insert, original magnification 200x), (C) CD10 (40x), and (D) focally strong positivity for CK7 (40x).
rt-2013-4-e57-g003.jpg
PMC3882929_01_rt-2013-4-e57-g003.jpg
fig003
The tubulocystic carcinoma cells showed diffuse strong immunoreactivity (Figure 3) for AMACR, AE1/AE3, CK8/18, CD10 and PAX2, and focally strong immunoreactivity for CK7 (Figure 3D), EMA, Vimentin and 34BE12.
Ultrastructural features of tubulocystic carcinoma. Type I cells (A) and (B) at 8250x and at 27,500x (C). Type I cells have irregular nuclear contours (A), well-formed microvilli (A-B), rootlets (C, small arrow), and prominent nucleoli (B). Type I cells contain numerous mitochondria, many of which have dense plaques (C, larger arrow). Type II cells (D) lack microvilli and contain numerous mitochondria in dense plaques (11,000x).
rt-2013-4-e57-g004.jpg
PMC3882929_01_rt-2013-4-e57-g004.jpg
fig004
The type I cells (Figure 4A-C) were composed of cuboidal cells bound on their luminal surfaces by tight junctions. The nuclear contour of these cells ranges from irregular (Figure 4A) to oval (Figure 4B). Nucleoli were prominent (Figure 4B). There were well-formed brush borders with long microvilli with prominent rootlets (Figure 4C). The cytoplasm of these cells had numerous mitochondria, many of which contained dense plaques (Figure 4C). The type II cells (Figure 4D) were present in a single layer, with desmosomal junctions and luminal surfaces bound by tight junctions. The surfaces of these type II cells were devoid of microvilli (Figure 4D).