A 52-year-old man was referred to our hospital because of a growing left renal tumor. A contrast-enhanced CT scan revealed the presence of a 93-mm tumor in the upper pole of the left kidney (Fig. a,b) with tumor thrombus observed in the left renal vein (Fig. c). The tumor was gradually enhanced from the corticomedullary phase to the excretory phase. Enlarged lymph nodes were present at the left external iliac lesion; they were extra-regional lymph nodes and no other distant metastasis was observed (Fig. d). We diagnosed him as having left RCC classified as cT3aN0M1.\nOpen radical nephrectomy and dissection of left-sided pelvic lymph nodes were performed. The tumor and lymph nodes were examined macroscopically and microscopically. Macroscopically, a 80 × 80-mm, gray–whitish and solid tumor with necrotic tissue was located in the upper pole of the resected left kidney. Microscopically, the tumor consisted of a tubular and partly papillary structure (Fig. a). The neoplastic cells were cuboidal with eosinophilic cytoplasm. The Fuhrman nuclear grading system is used to describe the RMTSCC., This case was classified as Fuhrman nuclear grade 3 (Fig. b). The tumor was invaded into left renal vein, and metastatic lymph nodes were found at the left external iliac area (Fig. c). Fascicular growth with spindle cells and mucin stained by Alcian blue stain were found (Fig. a). Immunohistochemical findings showed the neoplastic cells to be diffusely positive for AMACR (Fig. b) and CK 7 (Fig. c). CD 10 was negative in the neoplastic cells (Fig. d). Although Ki-67 and p53 were negative in the neoplastic cells with low nuclear grade, they were positive in the neoplastic cells with high nuclear grade (Fig. e,f). We subsequently diagnosed him as having left RMTSCC classified as pT3aN0M1.\nThree months after nephrectomy, a PET-CT scan showed metastasis at the second lumbar vertebra with a maximum standard uptake value of 5.7 (data not shown). Six months after nephrectomy, vertebrectomy was performed for metastasis at the second lumbar vertebra. The pathological findings showed metastasis of the RMTSCC to the second lumbar vertebra. Nine months after nephrectomy, another PET-CT scan showed two 10-mm lymph nodes at the left internal iliac lesion with a maximum standard uptake value of 5.1 (data not shown). These were not regional lymph nodes of RCC, but he was not suffering from other causative diseases such as prostate or rectal cancer. Therefore, we diagnosed these lymph nodes as metastasis of RMTSCC. We are planning on administration of tyrosine kinase inhibitor.
A 43-year-old Malay man presented to our facility with a three-month history of fever, non-productive cough and weight loss. He was a chronic smoker and had no significant medical history. Results of a physical examination were unremarkable. A chest radiograph revealed a large right lower zone lung lesion, and a subsequent computed tomography (CT) scan of the thorax and abdomen revealed a large heterogeneously enhancing soft tissue mass in the right lower lobe of the lung with intra-cavitary extension into the left atrium via the right inferior pulmonary vein (Figure ). Transthoracic needle aspiration of this mass was suggestive of carcinoma. Surgery was performed for the resection of this mass; a right posterior lateral thoracotomy was performed, followed by a right lower lobectomy. The left atrium was opened at the inferior part of the superior pulmonary vein and the tumor resected with a small cuff of left atrium. The entire tumor and right lower lobe was delivered en bloc, and the left atrial defect subsequently patched. Histology demonstrated a high-grade clear cell sarcomatoid tumor, suggestive of metastatic clear cell renal cell carcinoma, a diagnosis specifically considered by the pathologist. On immunohistochemistry, the lesion was focally positive for epithelial membrane antigen (EMA), CD10 and vimentin, but negative for anticytokeratin CAM5.2, thyroid transcription factor-1 (TTF-1), smooth muscle actin (SMA), S100, HMB-45, Melan-A, Hepar and synaptophysin. However, as no renal lesion was evident on the CT scan (Figure ), a diagnosis of alveolar soft part sarcoma was considered. An additional extensive investigation did not reveal a primary lesion or any other metastatic lesions.\nThen, four months later, our patient developed a subcutaneous mass in his left loin. A CT scan of the abdomen confirmed a large 11 cm tumor occupying nearly the entire right kidney with involvement of the pelvicalyceal system and proximal ureter (Figure ). The tumor also extended into the right renal vein and the inferior vena cava, with a 2 cm soft tissue nodule was seen in the subcutaneous layer of the left flank. Further imaging of the thorax demonstrated multiple lung nodules, a large right pleural-based mass and an enlarged subcarinal lymph node. A bone scan was performed, and suggested involvement of the right humeral head and multiple thoracic vertebrae. Excision biopsy of the subcutaneous nodule was performed, and histology demonstrated a tumor morphologically similar to the initially resected lung lesion, suggestive of a high-grade clear cell renal cell carcinoma with sarcomatoid differentiation (Figure ). On immunohistochemistry, the tumor was strongly positive for vimentin, CD10, focally positive for epithelial membrane antigen, melan-A and negative for TTF-1, S100, inhibin and synaptophysin (Figure ) The positive vimentin and negative inhibin results weighed against the likelihood of an adrenocortical tumor.\nOur patient was given palliative first-line therapy of sunitinib, with initial best response of stable disease. After three cycles of sunitinib, the disease progressed; our patient declined any further therapy and he eventually died 13 months after his initial lung resection.