case_images: PMC11350386_01
case_images: Contrast-enhanced CT-scan of the whole abdomen. (A) Renal mass with renal vein thrombosis (arrow). (B) Intratumoral calcifications (arrows). (C) Large heterogeneously-enhancing mass (star) arising from the kidney.
case_images: JKCVHL-11-040-g001.jpg
case_images: PMC11350386_01_JKCVHL-11-040-g001.jpg
case_images: F1
case_images: A computed tomography (CT) scan of the abdomen (Figure 1) revealed a large, lobulated, heterogeneously-enhancing renal mass (Figure 1C) with internal calcifications (Figure 1B) and hypodense necrotic areas. Thrombosis of the right renal vein and inferior vena cava were also detected (Figure 1A).
case_images: Photomicrographs of hematoxylin and eosin-stained sections exhibiting: (A) variable tumor architecture and necrosis (40x), (B) WHO/ISUP Grade 4 nuclei and cytoplasmic clearing (100x), (C) psammoma bodies (100x), (D) melanin pigments (40x).
case_images: JKCVHL-11-040-g003.jpg
case_images: PMC11350386_01_JKCVHL-11-040-g003.jpg
case_images: F3
case_images: A large tumor thrombus was identified within the renal vein.Microscopic sections revealed a tumor with predominantly lobulated, nested, and fused papillary architecture, characterized by central areas of necrosis bordered by thin hyalinized and vascularized septa (Figure 3A). The neoplastic cells exhibited moderate to marked pleomorphic, with vesicular nuclei, occasional multinucleate forms, prominent nucleoli, abundant pale eosinophilic to clear cytoplasm, and fairly distinct cell borders (Figure 3B). Several psammoma bodies (Figure 3C) and scattered foci of tumor cells containing melanin pigments (Figure 3D) were identified.
case_images: Immunohistochemistry studies. (A) Diffuse nuclear expression of TFE3 (40x). (B) Diffuse positivity for AMACR (40x). (C) Negative CA IX expression (40x). (D) Focal cytoplasmic granular Melan-A expression after bleaching (100x). TFE3, transcription factor binding to IGHM enhancer 3. AMACR, alpha-methylacyl-CoA racemase.
case_images: JKCVHL-11-040-g004.jpg
case_images: PMC11350386_01_JKCVHL-11-040-g004.jpg
case_images: F4
case_images: Immunohistochemistry revealed diffusely positive expression of TFE3 (Figure 4A) and alpha-methylacyl-CoA-racemase (AMACR) (Figure 4B) in almost all tumor cells. Negativity for carbonic anhydrase IX (Figure 4C), effectively ruled out the differential diagnosis of clear cell renal cell carcinoma. Following a bleaching protocol, occasional melan-A expression in neoplastic cells was observed (Figure 4D).