Dataset for reporting of thymic epithelial tumours: recommendations from the International Collaboration on Cancer Reporting (ICCR).

AIMS: The International Collaboration on Cancer Reporting (ICCR) is a not-for-profit organization formed by the Royal Colleges of Pathologists of Australasia and the United Kingdom, the College of American Pathologists, the Canadian Association of Pathologists-Association Canadienne des Pathologists in association with the Canadian Partnership Against Cancer, and the European Society of Pathology. Its goal is to produce standardized, internationally agreed, evidence-based datasets for use throughout the world. METHODS AND RESULTS: This article describes the development of a cancer dataset by the multidisciplinary ICCR expert panel for the reporting of thymic epithelial tumours. The dataset includes 'required' (mandatory) and 'recommended' (non-mandatory) elements, which are validated by a review of current evidence and supported by explanatory text. Seven required elements and 12 recommended elements were agreed by the international dataset authoring committee to represent the essential information for the reporting of thymic epithelial tumours. CONCLUSIONS: The use of an internationally agreed, structured pathology dataset for reporting thymic tumours provides all of the necessary information for optimal patient management, facilitates consistent and accurate data collection, and provides valuable data for research and international benchmarking. The dataset also provides a valuable resource for those countries and institutions that are not in a position to develop their own datasets.

[A case of endocrine cell carcinoma of the ascending colon with liver metastasis treated with hepatectomy after excision of the primary lesion and systemic chemotherapy].

A 77-year-old man who complained of melena was admitted to our department. Colonoscopy revealed a type 2 tumor in the hepatic flexure of the ascending colon. Biopsy examination revealed a poorly differentiated adenocarcinoma. Abdominal computed tomography(CT)revealed 3 tumors within the posterior segment of the right hepatic lobe. Initially, a right hemicolectomy was performed. Immunohistochemically, the tumor was diagnosed as an endocrine cell carcinoma. After surgery, a capecitabine, oxaliplatin, and bevacizumab(CapeOX/BEV)regimen was administered. However, after 5 chemotherapy courses, abdominal CT revealed enlargement of the 3 tumors in the posterior segment of the right hepatic lobe. There was no metastasis besides the liver metastasis. The patient underwent a radical hepatectomy of the posterior segment. At 8 months post-surgery, the patient remains alive and well. Endocrine cell carcinoma of the colon and rectum is usually malignant and is associated with a very poor prognosis because of rapid hematogenous or lymphogenous metastasis. Effective multimodal treatment regimens, including surgery and new chemotherapies such as molecular targeted therapies, should be established to improve the prognosis of patients with endocrine cell carcinomas of the colon and rectum.

Histopathological characteristics of stenosing flexor tenosynovitis in diabetic patients and possible associations with diabetes-related variables.

PURPOSE: To compare the histopathological findings of stenosing flexor tenosynovitis (SFTS) in diabetic patients with those in nondiabetic patients and to analyze the predominant characteristics of SFTS in diabetic patients by statistical methods. METHODS: We included 63 patients (63 specimens) who underwent excision of A1 pulleys for SFTS. A total of 38 patients (38 digits) were diabetic and 25 (25 digits) were nondiabetic. We obtained specimens from the proximal one-third of each A1 pulley and analyzed them by histological and immunohistochemical methods. After we identified the predominant histopathological characteristics of SFTS in patients with diabetes, we performed multiple logistic regression analysis to examine the possible associations between the histopathological characteristics and diabetes-related variables. RESULTS: We divided histopathological findings into 3 types in both diabetic and nondiabetic groups. Types 1 and 2 showed fibrocartilage metaplasia including fibrocartilage-like cells surrounded by basophilic extracellular substances. Type 2 was characterized by the presence of granulation tissue in the middle layer, which was not recognized in type 1. The granulation tissue contained newly formed microvessels, stromal cells, a small number of inflammatory cells, and extracellular matrix that showed myxomatous degeneration. Type 3 showed a decrease in fibrocartilage-like cells with surrounding extracellular eosinophilic substances, which was similar to hyaline degeneration. The histopathological features of type 2 were found in 68% of the diabetic group and in 28% of the nondiabetic group. This difference was statistically significant. The findings of type 2 were significantly associated with the severity of diabetic retinopathy and hemoglobin A1c values in the diabetic group. CONCLUSIONS: Type 2 findings were more frequent in the diabetic group than in the nondiabetic group. A pathomechanism to accelerate neovascularization and hypercellularity in the granulation tissue in the middle layer of A1 pulley may exist, especially in diabetic patients with severe retinopathy and poorly controlled hyperglycemia.

Clinical significance of DJ-1 as a secretory molecule: retrospective study of DJ-1 expression at mRNA and protein levels in ductal carcinoma of the breast.

AIMS: DJ-1 is a molecule secreted into serum by some breast cancer cells. However, little is known about the clinical significance of the DJ-1 expression. METHODS AND RESULTS: Expression of DJ-1 protein was examined by immunohistochemistry, and expression of DJ-1 mRNA was detected using in-situ hybridization in 273 invasive ductal carcinomas (IDCs) and 41 ductal carcinomas in situ (DCISs) of the breast, and also in breast cancer cell lines. Breast cancer cells were examined for their secretion of DJ-1 using immunoblot analysis. By immunohistochemistry DJ-1 protein expression was lower than adjacent non-cancerous epithelium in 6 (14.6%) of the 41 DCISs and 146 (53%) of the 273 IDCs, even although all 314 carcinomas retained expression of DJ-1 mRNA, which was higher than that in adjacent non-cancerous epithelium in 220 cases (70%). Patients with IDC whose cancer cells showed low expression of DJ-1 protein had significantly shorter disease-free survival (P = 0.0152) and overall survival (P = 0.0196) than those whose cancer cells retained DJ-1 expression. MDA-MB-231 cells, which secreted DJ-1, showed low expression of DJ-1 protein. CONCLUSIONS: Low expression of DJ-1 protein with high expression of its mRNA, which may reflect a secretory expression pattern, is predictive of poor outcome in patients with IDC.

Phase II study of intensive post-remission chemotherapy and stem cell transplantation for adult acute lymphoblastic leukemia and lymphoblastic lymphoma: Japan Clinical Oncology Group Study, JCOG9402.

OBJECTIVE: To evaluate the efficacy and safety of intensive post-remission chemotherapy for untreated patients aged 15-69 years with adult acute lymphoblastic leukemia and lymphoblastic lymphoma in a multicenter Phase II study. METHODS: The chemotherapy regimen consisted of induction, post-remission and maintenance for 2 years. The primary endpoint was 5-year progression-free survival, and secondary endpoints included complete remission rate, overall survival and adverse events. Among 115 patients enrolled, 108 eligible patients [median age, 33.5 years (range, 15-69)] including 96 acute lymphoblastic leukemia and 12 lymphoblastic lymphoma were assessed. Other major characteristics were male 50%, T-cell phenotype 21%, Philadelphia chromosome 22%, B-symptom+ 35% and performance status 2/3 22%. RESULTS: Eighty-seven patients achieved complete remission (81%; 95% confidence interval 72-88%), while five (5%) died during the chemotherapy protocol. The median overall survival and progression-free survival were 1.8 years (95% confidence interval, 1.5-2.6) and 1.2 years (95% confidence interval, 0.8-1.6), respectively. Their 5-year overall survival and progression-free survival were 29 and 28%, respectively. The 5-year overall survival of 31 patients who underwent allogeneic (n = 19) or autologous (n = 12) stem cell transplantation during first complete response was 51%. Major non-hematologic toxicities of Grade 3 or greater were infections (21%) and pulmonary complications (6%). When compared with the investigators' previous Phase II trials, JCOG9402 improved progression-free survival and overall survival when compared with JCOG8702; however, it did not show improvement when compared with JCOG9004. CONCLUSIONS: Although the intensified induction and post-remission chemotherapy was feasible and 28% of the patients with adult acute lymphoblastic leukemia or lymphoblastic lymphoma achieved long-term progression-free survival, JCOG9402 did not show improvement.

[A case of hepatic artery aneurysm that had formed asymptomatically and penetrated into the duodenum].

A 41-year-old man was admitted to our hospital with gastrointestinal bleeding. Esophagogastroduodenoscopy revealed a submucosal protrusion with erosion in the duodenal bulb which was thought to be the bleeding source. Dynamic CT scan, ultrasonography and angiography of the abdomen revealed a hepatic artery aneurysm and a dilated celiac artery that dissected from its origin. Although we considered percutaneous transcatheter arterial embolization with metallic coils, we chose surgical resection and vascular reconstruction to prevent hepatic ischemia resulting from interruption of collateral circulation. On the 8(th) day, hepatic artery aneurysmectomy and revascularization with a great saphenous vein was carried out without any severe complication. The pathological specimen demonstrated segmental arterial mediolysis.

Disappearance of recurrent thymic epithelial tumor following corticosteroid and cyclosporine treatment: A case report.

Thymic epithelial tumors (TETs) are considered orphan neoplasms, and treatment options for recurrent or metastatic stages are limited. Here, we have reported a case of recurrent TET that showed complete remission after receiving high-dose corticosteroids followed by low-dose corticosteroids and cyclosporine. No recurrence was observed for the next 2 years. The effects of corticosteroids on the TET and the associated pure red cell aplasia led to adjustment of the diagnosis from thymic carcinoma to thymoma. Low-dose corticosteroids and cyclosporine might be the reason for remission maintenance.

Surface CD3-negative monomorphic epitheliotropic intestinal T-cell lymphoma.

Intestinal T/NK-cell lymphomas include enteropathy-associated T-cell lymphoma (EATL), monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), indolent T-cell lymphoproliferative disorders of the GI tract (ITCLPD), extranodal NK/T-cell lymphoma, nasal type (ENKTL), and intestinal T-cell lymphoma NOS (ITCL-NOS). Here we describe a case of surface CD3-negative MEITL. A 63-year-old Japanese female had a tumor located in the conglomerated ileum, which formed multiple mass lesions. The resected tissue showed a diffuse infiltration of monomorphic medium-sized lymphocytes with epitheliotropism. Flowcytometry using a fresh specimen of the tumor revealed positivity for CD7, CD8, CD38, and CD56, but not surface CD3. On immunohistochemistry, the tumor showed positivity for cytoplasmic CD3, CD8, CD56, TIA-1, Granzyme B, and perforin. EBER with in situ hybridization was negative. Moreover, H3K36me3, which is negative in MEITL with SETD2-mutation, was positive. This is an important case of MEITL due to its oncogenesis.

Negative E-cadherin expression on bone marrow myeloma cell membranes is associated with extramedullary disease.

Background: The loss of E-cadherin expression and the induction of N-cadherin are known as hallmarks of the epithelial-to-mesenchymal transition, an essential initial step in the process of metastasis in solid tumors. Although several studies have reported expressions of these cadherins in patients with multiple myeloma (MM), their clinical significance is unknown as MM cells are non-epithelial. Methods: In this study, we examined the expression of E- and N-cadherins by immunohistochemistry using bone marrow (BM) biopsy specimens from 31 newly diagnosed MM patients and in subsequent biopsy specimens from six of these. Results: Negative E-cadherin expression on BM myeloma cell membranes was significantly associated with the presence of soft-tissue masses arising from bone lesions and breaking through the cortical bone, referred to as extramedullary disease (EMD). Conclusions: Given the aggressive nature of EMD, our study suggests that screening for E-cadherin using BM immunohistochemistry is one measure that could predict the development of EMD in patients with MM.

Overexpression of HER2 signaling to WAVE2-Arp2/3 complex activates MMP-independent migration in breast cancer.

The final signal for triggering the formation of lamellipodia that initiate directional migration of mammalian cells is binding of the Wiskott-Aldrich syndrome (WASP)/WASP family verproline-homologous protein 2 (WAVE2) to the actin-related protein 2 and 3 (Arp2/3) complex. This WAVE2-Arp2/3 signal is suggested to be enhanced in some breast cancers, facilitating invasion, and/or metastasis. Here, we demonstrated one cause of the enhanced signal using four breast cancer cell lines (SKBR3, AU565, MCF7, and MDA-MB-231). The WAVE2-Arp2/3 signal was estimated semi-quantitatively by counting the number of lamellipodia expressing both WAVE2 and Arp2 using high-power confocal laser microscopy. Higher expression of the WAVE2-Arp2/3 signal was detected in SKBR3 and AU565, which have HER2 gene amplification, than in the other two cell lines that lack HER2 gene amplification. Trastuzumab suppressed both the formation of lamellipodia and migration in a Boyden chamber experiment in SKBR3 and AU565. When the HER2 gene was transfected into MCF7, the number of both lamellipodia and migrated cells was increased. This enhancement of migration did not occur in the presence of extracellular matrix, and zymographic analysis showed no clear difference between HER2 gene-transfected cells and MCF7 cells. Immunohistochemical analysis of 115 cases of breast cancer revealed that coexpression of WAVE2 and Arp2 was significantly correlated with HER2-overexpression (P < 0.0001). These data indicate that an abnormal signal resulting from HER2 gene amplification activates lamellipodia formation in breast cancer cells, which initiates their metalloproteinase-independent migration.

Histopathological predictors of regional lymph node metastasis at the invasive front in early colorectal cancer.

AIMS: In early colorectal cancer (ECC), prediction of lymph node (LN) metastasis is vital for the decision of additional surgical treatment after endoscopic mucosal/submucosal resection. The aim of this study was to determine the relationship between LN metastasis and comprehensive histopathological findings including the cancer microenvironment in ECC. METHODS AND RESULTS: Using 111 ECC cases, including 36 cases with LN metastasis, histopathological observations and immunohistochemistry for lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1), von Willebrand factor, matrix metalloproteinase-7 (MMP-7), CXC chemokine ligand-12 (CXCL12) and angiopoietin-like-4 (ANGPTL4) were conducted. Relationships between LN metastasis and growth pattern, status of muscularis mucosae, depth of cancer invasion, overall histopathological type, histopathological type at the invasive front, tumour budding, neutrophil infiltration in cancer cells (NIC), fibrotic cancer-stroma type, Crohn's-like lymphoid reaction, microscopic abscess formation and lymphatic invasion were determined. In addition, the expression of MMP-7, CXCL12 and ANGPTL4 in cancer cells at the invasive front were also considered in the context of LN metastasis. By multivariate analysis, lymphatic invasion, NIC and MMP-7 expression at the invasive front were independent predictors of LN metastasis. CONCLUSIONS: LN metastasis is regulated not only by the characteristics of cancer cells but also by microenvironmental factors of lymphatics and neutrophils, especially at the invasive front.

[Pathological complete response in advanced gastric carcinoma by S-1/CDDP combination chemotherapy].

A59 -year-old woman was referred to our hospital for a close examination and treatment of an advanced gastric carcinoma. A physical examination and CT scan showed that the right cervical and axillar lymph nodes were swelling, and a histopathological examination of the axillar lymph node revealed metastatic growth of the gastric carcinoma (Stage IV). Then, we started S-1/CDDP combination chemotherapy. S-1 (80 mg/m2/day)was orally administered for 3 weeks followed by 2 weeks of rest, and CDDP (60 mg/m2) was administered by drip on day 8. Since the distant metastases were greatly reduced after 6 courses of combination therapy, a distal gastrectomy with lymph nodes dissection (D2) was performed. Histopathological examination of the resected tissues revealed no residual cancer cells, suggesting a pathologically complete response. The clinical course after the operation went well without any complications, and the patient is alive with no evidence of recurrence 1 year after surgery. S-1/CDDP combination chemotherapy appears to be one of the effective treatments for advanced gastric carcinoma.

[Advanced gallbladder cancer that showed complete response to gemcitabine plus S-1 chemotherapy].

A 57-year-old man with advanced gallbladder cancer and accompanying hepatic, colonic and duodenal invasion and para-aortic lymph node metastasis was referred to our hospital. Gemcitabine plus S-1 administration was chosen. Gemcitabine was administered intravenously at a dose of 1000 mg/m(2) on days 1 and 15, and repeated every 4 weeks. S-1 was administered orally at a dose of 40 mg/m(2) b.i.d. on days 1-14. Chemotherapy was effective for the primary gallbladder tumor and lymph node metastasis. The primary tumor and metastatic lymph nodes were shown to have disappeared by a FDG-PET CT study after 10 courses of chemotherapy. Informed consent was obtained prior to performing surgery of the primary lesion. Pathological examination showed fibrosis and a small focus of residual cancer in the resected gallbladder. Complete resection was achieved as all the margins were negative. The findings suggest that gemcitabine plus S-1 treatment may be effective against advanced gallbladder cancer.

Clinical characteristics of patients with B-cell lymphoma enrolled in clinical trials for aggressive lymphoma in Japan: Japan Clinical Oncology Group - Lymphoma Study Group study - JCOG0108A.

The clinical characteristics of B-cell lymphoma (BCL) were studied through the combined analysis of six clinical trials conducted by the Japan Clinical Oncology Group - Lymphoma Study Group (JCOG-LSG) for aggressive lymphoma in the 1990s, before the introduction of rituximab. Through a central pathological review, 829 patients were diagnosed with BCL according to the World Health Organization classification and treated with doxorubicin-containing combination chemotherapies. Of these patients, 642, 104, 30, and 24 patients were diagnosed with diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), mantle cell lymphoma (MCL), and marginal zone lymphoma (MZL), respectively. The overall survival (OS) of FL and MZL patients was higher than that of patients with DLBCL and MCL. The OS of the MCL patients was higher than that of DLBCL patients in the first 5 years, but MCL had the lowest survival after 5 years. The OS of DLBCL patients was clearly stratified by the international prognostic index and showed data compatible with that of aggressive lymphoma in the pre-rituximab era. These results established the clinical aspects of BCL in a large number of patients treated in prospective studies during the pre-rituximab era in Japan.

Epidermal growth factor-dependent enhancement of invasiveness of squamous cell carcinoma of the breast.

Factors that promote the aggressiveness of squamous cell carcinoma of the breast are not well understood. To examine the involvement of cell motility and the mechanism of this behavior, a squamous cell carcinoma cell line of the breast (HBC9) was established from a metastatic lymph node of a Japanese woman. HBC9 expressed epidermal growth factor receptor (EGFR), but was negative for Her2 or Her3.The invasive ability of HBC9 was compared with that of four breast ductal carcinoma cell lines by Matrigel invasion assay. EGF stimulation induced the formation of surface protrusions and cell migration in HBC9 cells, and significantly increased the number of cells migrating through the Matrigel. The invasive ability of HBC9 was compared with other cell lines of breast carcinoma; it was much greater than that of MCF-7, BT474, or HBC5, but did not differ significantly from that of MDA-MB-231. Observation of the surface protrusions of HBC9 by confocal laser microscopy revealed co-localization of Arp2 and N-WASP with actin polymerization, detected by visualization with phalloidin, indicating that the protrusions induced by EGF were invadopodia. In HBC9 cells, cortactin also co-localized with the N-WASP/Arp2/3 complex in the protrusions. Immunohistochemistry of 12 cases of squamous cell carcinoma of the breast revealed expression of cortactin and EGFR in all of them, and this was confirmed by western blotting in two cases. These results suggest that EGF-dependent enhancement of cell motility by formation of invadopodia associated with cortactin is a cause of the clinical aggressiveness of squamous cell carcinoma of the breast.

Clinical response of large cell neuroendocrine carcinoma of the lung to perioperative adjuvant chemotherapy.

Patients with large cell neuroendocrine carcinoma (LCNEC) of the lung are considered to have poor prognosis. However, the benefit of adjuvant chemotherapy for these patients has not been established. In this study, we retrospectively evaluated the efficacy of perioperative chemotherapy for patients with completely resected LCNEC in a single-center setting. From 1999 through 2007, 45 patients with surgically resected LCNEC or mixed LCNEC containing at least one portion of the neuroendocrine differentiation or morphology in non-small cell lung carcinoma were enrolled as participants of this study. Survival rates were calculated by the Kaplan-Meier method. Differences between survival curves were computed with the log-rank test. For multivariate analysis, the Cox's proportional hazards regression model was used to evaluate variables that were significant predictors of survival. Of 1397 patients undergoing surgical resection for primary lung cancer from 1999 to 2007, 45 (3.2%) were classified as LCNEC. Thirty-six (80%) patients were men, and nine (20%) were women. Twenty-four (92%) of 26 patients were present or past smokers. Twenty-three (41%) of 45 patients received perioperative chemotherapy, including seven induction chemotherapies and 16 adjuvant chemotherapies. Survival of patients who underwent perioperative adjuvant chemotherapy was significantly higher than that of those who received surgery alone (P = 0.04). The 5-year survival rate of patients who underwent perioperative adjuvant chemotherapy was 87.5%, whereas that of patients who underwent surgery alone was 58.5%. Even in stage I cases, perioperative adjuvant chemotherapy still favors survival compared with surgery alone. In the Cox proportional hazard multivariate analysis, surgery with or without chemotherapy showed an independent prognostic influence on overall survival (P = 0.0457). Patients who received surgery alone were 9.5 times more likely to die than patients who underwent surgery plus chemotherapy. In conclusion, perioperative chemotherapy will be needed to improve survival in patients with LCNEC. As the population of LCNEC is small, it has been difficult to conduct randomized controlled trials to show the survival benefit of adjuvant chemotherapy. This should be, therefore, evaluated further in prospective multi-institutional phase II trials.

POEMS syndrome with idiopathic portal hypertension: autopsy case and review of the literature.

Polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes (POEMS) syndrome is a rare multi-system disease. Reported herein is an autopsy case of POEMS syndrome in a subject who developed idiopathic portal hypertension (IPH). The patient was a 38-year-old woman who was initially admitted to the Saiseikai Central Hospital because of polyneuropathy and edema. Diagnosis of POEMS syndrome was established on additional symptoms (splenomegaly and papilloedema) and serum M-protein. Corticosteroid was given for 10 years. The patient was admitted again at the age of 48 years because of gastrointestinal bleeding due to portal hypertension. The patient died of hepatoencephalopathy at 58 years of age. The liver at autopsy demonstrated dense portal fibrosis and obliteration of small portal vein branches, which are characteristic histological findings of IPH. Portal hypertension is a rare symptom in POEMS syndrome. Only three cases of IPH associated with POEMS syndrome (including the present one) have been reported so far. In the previous two reports, liver biopsy failed to determine the cause of portal hypertension. This is the first report on the occurrence of histological findings compatible with IPH in the liver. Although it is not confirmed whether IPH is related to POEMS syndrome, elevated serum cytokines such as vascular endothelial growth factor and coagulation abnormality could have contributed to the development of IPH in the present case.

Ectopic hamartomatous thymoma--a truly rare neoplasm: report of a case.

An ectopic hamartomatous thymoma is an extremely rare benign neoplasm that commonly occurs in the lower neck region. It has distinctive pathological features that include haphazardly arranged spindle cells, epithelial cells, and mature fat tissue. Its histogenesis is still controversial. This report presents a case of a 26-year-old man with ectopic hamartomatous thymoma in the left supraclavicular region, and discusses the current knowledge regarding this type of lesion. Clinicians as well as pathologists should be aware of the existence of this disease so that it can be identified correctly.

[IPSILATERAL SYNCHRONOUS MUCINOUS TUBULAR AND SPINDLE CELL CARCINOMA AND CLEAR CELL PAPILLARY RENAL CELL CARCINOMA: A CASE REPORT AND REVIEW OF THE LITERATURE].

Renal cell carcinoma (RCC), the most common solid lesion of the kidney, accounts for approximately 2%-3% of all malignancies among adults. Clear cell carcinoma and papillary cell carcinoma are the most common types of renal tumors. Some case reports have described synchronous benign and malignant tumors in the same kidney. In particular, angiomyolipoma and RCC in patients with tuberous sclerosis (TSC) and non-TSC have been reported many times in the literature. However, unilateral concordance of malignant renal tumors is very rare; thus, only few cases have been reported in the literature.Here we report the case of a 58-year-old male who had ipsilateral synchronous mucinous tubular and spindle cell carcinoma (MTSCC) and clear cell papillary renal cell carcinoma (CCPRCC). Both cancers are rare and relatively recently defined subtypes of RCC. Additionally, both were successfully treated using partial nephrectomy. MTSCC has been a distinct entity in the World Health Organization classification of kidney tumors since 2004. The classic type of MTSCC is characterized by small elongated tubules lined with clear cuboidal or spindle cells with mucinous stroma. Neoplastic cells always exhibit low-grade histological features. However, unclassified variants of MTSCC, such as mucin-poor, papillary, high-grade, and sarcomatoid variants, have also been reported. MTSCC is considered to have a relatively good prognosis, but some patients with poor prognoses have recently been reported. CCPRCC is a recently recognized entity and represents the fourth most common variant of RCC. It has unique morphological and immunohistochemical features and shows indolent clinical behavior. Microscopically, CCPRCC may mimic other RCCs with clear cell features, such as clear cell RCC, translocation RCC, and papillary RCC, with clear cell changes. In 2006, CCPRCC was described as a subtype of renal tumors in patients with end-stage renal disease. However, currently, CCPRCC has also been shown to occur in kidneys with normal function.To the best of our knowledge, this is the first report of ipsilateral synchronous MTSCC and CCPRCC, which we present with a review of the pertinent literature.