PMC8133846_01
Abdominal computerized tomography scan showing (a) a heterogeneous mass occupying the right kidney (arrowhead). (b) The mass seems to arise from the renal parenchyma (arrowhead) and to extend into the renal vein lumen while compressing the inferior vena cava (arrow).
CRIPA2021-6637533.001.jpg
PMC8133846_01_CRIPA2021-6637533.001.jpg
fig1
An abdominal computerized tomography (CT) scan showed a 25 x 11 x 8 cm heterogeneous mass occupying the right kidney and extending into the renal vein lumen while compressing the IVC (Figure 1).
Gross examination of the tumor showed a gray-white whorled appearance with foci of hemorrhagic and necrotic changes. Presence of a peripheral rim of the normal kidney (star).
CRIPA2021-6637533.002.jpg
PMC8133846_01_CRIPA2021-6637533.002.jpg
fig2
A portion of the tumor occupied the renal vein lumen, but most of this huge tumor extended beyond the hilum area compressing the normal renal parenchyma (Figure 2).
Hematoxylin and eosin staining. (a) A spindle cell neoplasm arranged in alternating fascicles arising from the wall of the renal vein. (b) The cells are spindle shaped with elongated blunt-ended nuclei, coarse chromatin, and eosinophilic cytoplasm. Presence of pleomorphic cells showing marked nuclear pleomorphism, hyperchromasia, and prominent nucleoli. (c) The tumor is encapsulated (arrow) compressing the residual renal parenchyma. T: tumor; L: vascular lumen; WV: wall of the renal vein; R: renal tissue; arrow: tumor capsule.
CRIPA2021-6637533.003.jpg
PMC8133846_01_CRIPA2021-6637533.003.jpg
fig3
The renal vein's surgical resection margin was free of tumor (Figure 3).
Immunohistochemical study showing diffuse positivity for smooth muscle actin (a), H-caldesmon (b), and desmin (c).
CRIPA2021-6637533.004.jpg
PMC8133846_01_CRIPA2021-6637533.004.jpg
fig4
In the immunohistochemical study (Figure 4), the tumor cells showed diffuse positivity for smooth muscle actin (SMA), heavy chain caldesmon (H-caldesmon), and desmin.