Metastatic renal cell carcinoma involving colon with unusual histologic features and diagnostic challenges: A case report

Sarcomatoid and Rhabdoid Renal Cell Carcinoma: Clinical, Pathologic, and Molecular Genetic Features

Renal cell carcinoma (RCC) with sarcomatoid and rhabdoid morphologies has an aggressive biological behavior and a typically poor prognosis. The current 2022 WHO classification of renal tumors does not include them as distinct histologic entities but rather as transformational changes that may arise in a background of various distinct histologic types of RCC. The sarcomatoid component shows malignant spindle cells that may grow as intersecting fascicles, which is reminiscent of pleomorphic undifferentiated sarcoma. The rhabdoid cells are epithelioid cells with eccentrically located vesicular nuclei with prominent nucleoli and large intracytoplasmic eosinophilic inclusions. Studies have shown that RCCs with sarcomatoid and rhabdoid differentiation have distinctive molecular features. Sarcomatoid RCC harbors shared genomic alterations in carcinomatous and rhabdoid components, but also enrichment of specific genomic alterations in the sarcomatoid element, suggesting molecular pathways for development of sarcomatoid growth from a common clonal ancestor. Rhabdoid differentiation also arises through clonal evolution although less is known of specific genomic alterations in rhabdoid cells. Historically, treatment has lacked efficacy, although recently immunotherapy with PD-1/PD-L1/CTLA-4 inhibitors has produced significant clinical responses. Reporting of sarcomatoid and rhabdoid features in renal cell carcinoma is required by the College of American Pathologists and the International Collaboration on Cancer Reporting. This manuscript reviews the clinical, pathologic, and molecular features of sarcomatoid RCC and rhabdoid RCC with emphasis on the morphologic features of these tumors, significance of diagnostic recognition, the molecular mechanisms of tumorigenesis and differentiation along sarcomatoid and rhabdoid lines, and advances in treatment, particularly immunotherapy.

Descending Colon Metastasis of Renal Cell Carcinoma: An Unusual Site of Metastasis

Renal cell carcinoma (RCC) has a high metastatic potential. While metastasis to common sites like the lungs, liver, bones, and brain is well-documented, metastasis to the colon, particularly the descending colon, remains an uncommon occurrence. When RCC does metastasize to the gastrointestinal tract, it commonly spreads to the small bowel and stomach. There are few cases reported in literature involving RCC metastasis to the colon. The commonly affected areas within the colon include the rectosigmoid colon, splenic flexure, and transverse colon. We describe an 87-year-old male with a history of stage III RCC diagnosed three years ago, followed by left-sided nephroureterectomy, partial adrenalectomy, and perinephric lymph node dissection. He presented to the emergency department (ED) with melena and generalized abdominal pain for one week. Stool occult blood was positive. Computed tomography (CT) of the abdomen was significant for stable postsurgical changes related to prior left nephrectomy and colonic mass at the proximal descending colon. A colonoscopy revealed a necrotic appearing friable mass in the descending colon. The pathology of the mass revealed proliferated atypical cells positive for paired box 8 (PAX8), a cluster of differentiation 10 (CD10), RCC, and pan-cytokeratin and negative for caudal-type homeobox 2 (CDX2), thyroid transcription factor-1 (TTF-1), and a cluster of differentiation 68 (CD68), consistent with metastatic RCC.

Bleeding metastasis of renal cell cancer to anal canal treated with radiation

Renal cell cancer (RCC) has the ability to metastasize to various organs, including the anal canal which is reported to be the rarest location. An 88-year-old male patient who had previously been treated for right RCC subsequently developed distant metastases to the prostate, lungs, and small bowel. Four years following nephrectomy, the patient presented with a bleeding anal mass which was excised and has been proven to be an anal canal metastasis of RCC. Eight months post excision, regrowth occurred. The patient underwent stereotactic ablative body radiotherapy resulting in satisfactory regression during the 2-month follow-up period, without episodes of bleeding. The treatment options for metastatic post-nephrectomy disease should be considered with a multidisciplinary approach in order to achieve satisfactory symptom relief.

2.5D MFFAU-Net: a convolutional neural network for kidney segmentation

BACKGROUND

Kidney tumors have become increasingly prevalent among adults and are now considered one of the most common types of tumors. Accurate segmentation of kidney tumors can help physicians assess tumor complexity and aggressiveness before surgery. However, segmenting kidney tumors manually can be difficult because of their heterogeneity.

METHODS

This paper proposes a 2.5D MFFAU-Net (multi-level Feature Fusion Attention U-Net) to segment kidneys, tumors and cysts. First, we propose a 2.5D model for learning to combine and represent a given slice in 2D slices, thereby introducing 3D information to balance memory consumption and model complexity. Then, we propose a ResConv architecture in MFFAU-Net and use the high-level and low-level feature in the model. Finally, we use multi-level information to analyze the spatial features between slices to segment kidneys and tumors.

RESULTS

The 2.5D MFFAU-Net was evaluated on KiTS19 and KiTS21 kidney datasets and demonstrated an average dice score of 0.924 and 0.875, respectively, and an average Surface dice (SD) score of 0.794 in KiTS21.

CONCLUSION

The 2.5D MFFAU-Net model can effectively segment kidney tumors, and the results are comparable to those obtained with high-performance 3D CNN models, and have the potential to serve as a point of reference in clinical practice.

Metastatic renal cell carcinoma to pancreas and gastrointestinal tract: a clinicopathological study of 3 cases and review of literature

BACKGROUND

Renal Cell Carcinoma (RCC) metastasizes in approximately 20-30% cases. The most common sites for metastases are the lungs, bones, liver, and brain. Metastases of RCC in the gastrointestinal tract (GIT) are very rare. Metastatic RCC has a poor prognosis. We herein present a case series of three patients with metastatic disease in the colon, duodenum, and pancreas following complete resection of RCC.

METHODS

Hematoxylin and Eosin and immunohistochemical slides of 3 cases of RCC metastatic to GIT were reviewed. These cases were diagnosed between 2002 and 2019 at French Medical Institute for Mothers and Children (FMIC), Kabul, Afghanistan, and Aga Khan University Hospital (AKUH), Karachi, Pakistan. We also present a detailed review of published literature.

RESULTS

We reviewed cases of three patients, two females and one male, with a mean age of 57.3 years (range 40-67 years) who underwent nephrectomy for RCC. They developed metastases in the colon, pancreas, and duodenum, respectively 12-168 months (median time 156 months) following primary tumor resection. The patient with metastatic RCC in colon presented with abdominal pain and constipation. An ulcerated mass was found on colonoscopy 30 cm from the anal verge. Diagnosis of RCC with rhabdoid features was confirmed in both primary and metastatic tumors. The second patient developed a metastatic nodule in the head of pancreatic while the third patient developed metastatic nodules in the duodenum and pancreas which were detected by Computed Tomography (CT) scanning. Histopathological examination confirmed the presence of clear cell RCC in the metastatic nodules in both cases.

CONCLUSION

Metastatic RCC should be considered in the differential diagnosis of mass in the gastrointestinal (including pancreaticobiliary) tract especially in presence of a past history of RCC. These patients should be screened thoroughly by physical examination and appropriate imaging studies.