大城 久

INTRODUCTION: Spontaneous tumor regression (STR) is a rare phenomenon in which cancer cells partially or completely disappear without treatment. We report a case of intrahepatic cholangiocarcinoma demonstrating STR following endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA). CASE PRESENTATION: A 77-year-old male presented with acute cholecystitis 1 day after percutaneous coronary intervention for acute myocardial infarction. Conservative treatment and endoscopic retrograde gallbladder drainage were performed due to antiplatelet therapy. Cytology of bile juice unexpectedly revealed adenocarcinoma. Further imaging, including CT and mapping biopsy, failed to detect a tumor. Laparoscopic cholecystectomy with gallbladder bed resection showed no histological evidence of malignancy. Four months later, surveillance CT revealed a 15 × 15 mm lesion in segment 3 of the liver. EUS-FNA confirmed adenocarcinoma. Laparoscopic left lateral resection was performed; however, no viable cancer cells were identified, and the lesion was replaced by epithelioid granulomas. Immunohistochemistry demonstrated dense infiltration of CD8-positive cytotoxic T cells, suggesting an immune-mediated regression of the tumor. CONCLUSIONS: This case highlights the possibility of tumor regression in intrahepatic adenocarcinoma following EUS-FNA, potentially triggered by an immune response.

Cutaneous arteritis (CA) is a rare cutaneous manifestation of Crohn's disease. A 50-year-old woman with a 15-year history of CA was admitted to our hospital with a fever, abdominal pain, and hematochezia. Based on these symptoms and increased C-reactive protein levels, systemic vasculitis was considered. However, emergency colonoscopy revealed multiple longitudinal ulcers throughout the colon, thus suggesting Crohn's disease. Prednisolone (60 mg/day) was administered intravenously. A histopathological examination of the biopsied colonic mucosa revealed epithelioid granulomas, which confirmed the diagnosis of Crohn's disease. Because the systemic evolution of CA is rare, other comorbidities should be considered when patients with CA experience systemic manifestations.

Diagnosing intracranial space-occupying lesions in patients with AIDS is challenging because they have multiple possible causes. We report the case of a 49-year-old man with AIDS and diffuse large B-cell lymphoma (DLBCL) who presented with fever and impaired consciousness. He had initiated antiretroviral therapy (ART) and treatment for DLBCL 3 months previously, and treatment for pulmonary tuberculosis and tuberculous meningitis 1 month previously. Gd-DTPA-enhanced magnetic resonance imaging revealed multiple new cerebral ring-enhancing lesions. A left occipital lobe biopsy specimen revealed a necrotic epithelioid granuloma, and Mycobacterium tuberculosis was detected on brain tissue culture, leading to a diagnosis of an intracranial tuberculoma associated with immune reconstitution inflammatory syndrome (IRIS). He was treated with ART, antituberculosis therapy, and dexamethasone, and gradually recovered. This case demonstrates the utility of brain biopsy for confirming the diagnosis of tuberculoma.

A 53-year-old woman visited her district hospital complaining of right lower limb numbness 8 days after being diagnosed with COVID-19. She had been suffering diarrhea for 25 days before the hospital visit. Computed tomography showed multiple arterial and venous thromboses, and anticoagulation with a therapeutic dose of heparin was initiated. Acute aortic occlusion occurred on hospital day 5, and balloon thromboembolectomy was performed for revascularization of the lower limbs 9 hours after onset. Ulcerative colitis was diagnosed on postoperative day 7. With the anticoagulation and immunosuppression therapy, no thromboembolic event occurred postoperatively.

BACKGROUND: Minimal change nephrotic syndrome (MCNS) can be complicated by thymoma; however, no standard therapy for thymoma-associated MCNS has yet been established. We herein describe a case of steroid-resistant MCNS associated with thymoma, treated effectively with rituximab. CASE PRESENTATION: A 71-year-old Japanese man was referred to our department with severe proteinuria (20 g/gCr). Renal biopsy showed minimal change disease and computed tomography revealed an anterior mediastinal mass. Based on these findings, he was diagnosed with thymoma-associated MCNS. He was treated with oral prednisolone (50 mg/day) and cyclosporine, and underwent thymectomy and plasma exchange. However, no improvement in proteinuria was observed. He therefore received intravenous rituximab 500 mg, resulting in a marked decrease in proteinuria from 5328 to 336 mg/day after 1 week. CONCLUSIONS: This case suggests that rituximab might be an effective therapy in patients with steroid-resistant MCNS associated with thymoma.

BACKGROUND/AIM: In prostate cancer, robotic total prostatectomy is a popular treatment modality. However, prostate-specific antigen (PSA) recurrence after prostate cancer surgery remains a concern. Salvage radiotherapy is commonly used to treat PSA recurrence, but the recurrence rate after salvage radiotherapy is high, highlighting the need for better predictive markers. This study aimed to retrospectively evaluate the association between cribriform pattern and PSA recurrence in patients receiving radiotherapy after radical prostatectomy. PATIENTS AND METHODS: Data of 50 patients who underwent radiotherapy after total prostatectomy between January 2010 and May 2020 were retrospectively evaluated. The median age was 67 years. Among these patients, two cases involved postoperative irradiation, while 48 cases involved salvage irradiation after postoperative PSA recurrence. The median time from surgery to PSA recurrence was 38.3 months. The median radiation dose was 64 Gy in 32 fractions. Three-dimensional conformal radiation therapy was administered in 38 cases and intensity-modulated radiation therapy was used in 12 cases. Combined hormone therapy was administered in 21 cases. PSA levels were measured every 3 months after treatment. Statistical analysis between groups was performed by a t-test. RESULTS: The median follow-up period after radiotherapy was 31 months. No local recurrences were observed at the prostate bed, and no deaths related to prostate cancer were recorded during follow-up. However, 18 patients (36.0%) had PSA recurrence. The PSA recurrence rate based on the cribriform pattern was 17.6% in the none to moderate group (34 patients) and 75.0% in the severe cribriform pattern group (16 patients). The PSA recurrence rate was significantly higher in patients with a severe invasive cribriform pattern (p=0.001). No significant differences were observed in other histopathological characteristics. CONCLUSION: The cribriform pattern in surgical pathology specimens was found to be a useful predictor of PSA recurrence after postoperative radiotherapy.

A 54-year-old man was admitted with obstructive jaundice. Computed tomography showed common bile duct stricture and a tumor around the celiac artery. Repeated endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) and endoscopic retrograde cholangiopancreatography (ERCP) as well as a laparotomic biopsy around the celiac artery were diagnostically unsuccessful. Since the bile duct stricture progressed, EUS-FNA and ERCP were performed a third time, finally leading to the diagnosis of diffuse large B-cell lymphoma. The treatment plan and prognosis of obstructive jaundice differ greatly depending on the disease. It is important to conduct careful follow-up and repeated histological examinations with appropriate modifications until a diagnosis is made.

Chronic active Epstein-Bar virus infection (CAEBV) is known to cause various symptoms. Although pulmonary artery hypertension (PAH) has been reported as a cardiovascular complication of CAEBV, the mechanisms of PAH and the effects of treatment have not been fully elucidated. We experienced 4 adult patients with CAEBV complicated by PAH. All of them received treatment for PAH with a vasodilator followed by chemotherapy with or without allogeneic hematopoietic cell transplantation for CAEBV. In all of these patients, the transtricuspid pressure gradient improved under treatment with vasodilator, and further improvement was observed under treatment for CAEBV in 3 patients. Autopsy was performed in 2 patients, which revealed EBER-positive cells and a change in the pulmonary artery at each stage in the pathology. In conclusion, EBV-infected cells can cause vasculitis and finally PAH. However, PAH complicated with CAEBV can be improved by PAH medication and treatment of CAEBV.

Immunoglobulin G4 (IgG4)-related disease is established as a new clinical entity, characterized by high levels of plasma IgG4 and IgG4-positive plasma cell infiltration. However, the elevation of plasma IgG4 and infiltration of IgG4-positive cells have been observed in other diseases, including malignancy. We experienced a case of prominent IgG4-positive lymphadenopathy, which was diagnosed as a reactive lesion in response to lung cancer. The cancerous lesion was so small in size that it was difficult to reveal the coexisting lung cancer. Surgical lymph node biopsy and endobronchial ultrasound-guided transbronchial needle aspiration did not reveal lymph node metastasis of cancer. Mediastinal lymph node dissection finally revealed it. After the right upper lobectomy, the patient underwent postoperative chemotherapy and remains cancer-free after 1 year. Our case suggests that close examination and careful follow-up are necessary when IgG4-positive lymphadenopathy is observed.

Cytological detection of chordoma cells in the serosal cavity is challenging because of its rare presentation. Herein, we report a case of chordoma showing malignant pleural effusion accompanied by pleuropulmonary metastases in a 68-year-old woman. Cytological analysis was performed using pleural fluid obtained following thoracentesis. Conventional cytological staining demonstrated few clusters of large, atypical cells characterized by epithelial cell-like connectivity and rich cytoplasm with foamy and/or multivacuolar changes. The nuclei of these atypical cells were large and either round or oval with no conspicuous irregularities in the nuclear membrane. Periodic acid-Schiff staining of these atypical cells revealed fine granules in the cytoplasm. Giemsa staining showed foamy and/or multivacuolar cytoplasm in these cells, with metachromatic mucoid stroma in the surroundings. Immunocytochemistry analysis using cellblock showed these cells to be positive for broad cytokeratins, epithelial membrane antigen, S100 protein, vimentin, and Brachyury. To the best of our knowledge, this is the first case report in which chordoma cells were cytologically detected in pleural effusions. Our findings also suggest that conventional cytology combined with cellblock immunocytochemistry can increase the accuracy of chordoma cell detection in the serosal cavity.

Background Nonalcoholic fatty liver disease (NAFLD) is common in the general population but identifying patients with high-risk -nonalcoholic steatohepatitis (NASH) who are candidates for pharmacologic therapy remains a challenge. Purpose To develop a score to identify patients with high-risk NASH, defined as NASH with an NAFLD activity score (NAS) of 4 or greater and clinically significant fibrosis (stage 2 [F2] or higher). Materials and Methods This was a cross-sectional secondary analysis of data prospectively collected between April 2017 and March 2019 for a group of patients with NAFLD in Japan (Japan NAFLD, the derivation data set) with contemporaneous two-dimensional shear-wave elastography and biopsy-proven NAFLD (age range, 20-89 years). Three US markers (liver stiffness [LS, measured in kilopascals], attenuation coefficient [AC, measured in decibels per centimeter per megahertz], and dispersion slope [DS, measured in meters per second per kilohertz]) were determined, together with aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and the AST-to-ALT ratio. The best-fit multivariate logistic regression model for identifying patients with high-risk NASH was determined. Diagnostic performance was assessed by using the area under the receiver operating characteristic curve (AUC). The findings were validated in an independent data set (Korea NAFLD; age range, 20-78 years). Results The Japan NAFLD data set included 111 patients (mean age, 53 years ± 18 [standard deviation]; 57 men), 84 (76%) with NASH. The Korea NAFLD data set included 102 patients (mean age, 48 years ± 18; 43 men), 55 (36%) with NASH. The most predictive model (LAD NASH score) combined LS, AC, and DS. Performance was satisfactory in both the derivation sample (AUC, 0.86; 95% CI: 0.79, 0.93) and the validation sample (AUC, 0.88; 95% CI: 0.80, 0.95). The LAD NASH score showed a positive predictive value of 86.5% and a negative predictive value of 87.5% for high-risk NASH in the derivation sample. Conclusion A score combining three US markers may be useful for noninvasive identification of patients with high-risk nonalcoholic steatohepatitis for inclusion in clinical trials and pharmacologic therapy. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Lockhart in this issue.

PURPOSE: Attenuation imaging (ATI) is a new noninvasive ultrasound technique for assessing steatosis grade (S). However, validated region-of-interest (ROI) sampling strategies are not currently available. We investigated the diagnostic performance of various ATI-ROI positions for determining histopathologic S in patients with nonalcoholic fatty liver disease (NAFLD). METHODS: This retrospective study included 105 patients with biopsy-proven NAFLD. All attenuation coefficient (AC, dB/cm/MHz) measurements were obtained by the same hepatologist using a commercially available ultrasound system on the same day as liver biopsy. Mean (± standard deviation) age and body mass index of the patients were 53 (± 18) years and 27.1 (± 4.1) kg/m2, respectively. The numbers of patients with steatosis affecting < 5%, 5-33%, 33-66%, and > 66% of hepatocytes were 8, 50, 29, and 18, respectively. The ATI-ROI was placed at three different positions for AC measurement using a dedicated workstation: the upper edge of the area ROI, twice the depth of the liver capsule, and the lower edge of the area ROI. Diagnostic performance was evaluated using the area under the receiver-operating characteristic curve (AUC). RESULTS: The AUCs of AC at the three ATI-ROI positions were 0.734 (95% confidence interval [CI]: 0.470-0.998), 0.750 (0.639-0.861), and 0.878 (0.788-0.968) for S ≥ 1; 0.503 (0.392-0.615), 0.824 (0.741-0.907), and 0.809 (0.724-0.895) for S ≥ 2; and 0.606 (0.486-0.726), 0.849 (0.767-0.932), and 0.737 (0.626-0.848) for S = 3, respectively. CONCLUSION: For accurate steatosis grade assessment, the ATI-ROI should not be placed at the upper edge of the area ROI.

A 52-year-old man underwent pneumonectomy of the left lung for previously diagnosed primary spindle cell carcinoma (pT4aN1M0, stage III B) with programmed death-ligand 1 expression (tumor proportion score ≥95%) and without epidermal growth factor receptor gene mutation and anaplastic lymphoma kinase fusion gene. However, brain metastasis and chest wall tumor relapse occurred. Considering insufficient improvement with gamma knife treatment for brain metastasis and combination chemotherapy (paclitaxel, carboplatin, and bevacizumab), pembrolizumab monotherapy and palliative irradiation therapy for chest metastases were started after brain tumor volume reduction using craniotomy. Brain edema and chest wall metastases markedly improved following a pseudoprogression of the brain edema accompanied by a performance status decline; this effect continued until 11 cycles of pembrolizumab administration.

PURPOSE: Measurement of spleen stiffness (SS) using ultrasound (US) elastography is useful for predicting portal hypertension. However, the mechanism leading to increased SS remains unclear. We jointly developed a new US elastography system (Aplio i-series, Canon Medical Systems) that can easily measure organ viscosity (dispersion slope: DS). We analyzed the cause of increased SS by calculating the shear wave speed (SWs, which reflects fibrosis) and DS of the spleen in carbon tetrachloride (CCL4) rat liver cirrhosis models. METHODS: A total of 13 Sprague-Dawley rats were randomly divided into four groups (C group: 3 rats as control, 2D group: 3 rats injected with CCL4 twice in 1 week, 4D group: 4 rats injected 4 times in 1 week, 6W group: 3 rats injected twice a week for 6 weeks). The SWs and the DS of each group were calculated, and histopathological analysis was performed. RESULTS: The spleen SWs of the 6W group was significantly higher than that of the C group (p = 0.044). The spleen DS did not change after CCL4. The liver SWs of the 4D and 6W groups was significantly higher than that of the C group (p = 0.012 and 0.007, respectively) with fibrosis change on histopathology, and the DS of the 4D group was significantly higher than that of the C group (p = 0.033). Splenic fibrosis was confirmed in the 6W group, but inflammation and necrosis were not seen. CONCLUSION: SS increased due to fibrosis and can be predicted based on SWs and DS values.

INTRODUCTION: Breast adenomyoepithelioma (AME) is a rare tumor composed of myoepithelial cells and ductal or luminal cells. Most cases of AME are benign, but rare cases in which either or both cell types exhibited malignant features have been reported. Due to its rarity, no diagnostic criteria for malignancy have been established for AME. PATIENT CONCERNS: A 64-year-old woman presented with a mass in her right breast. Fine-needle aspiration cytology and biopsy examinations revealed lesions composed of spindle-shaped cells and round epithelial cells. AME was suspected, and partial mastectomy was performed. DIAGNOSIS: The tumor specimen showed AME, which mainly consisted of spindle-shaped myoepithelial cells with slight atypia, admixed with tubular luminal cells and small areas of atypical intraductal proliferative lesions. No apparent features of malignancy, such as necrosis or invasion, were seen in the myoepithelial cells or the luminal or intraductal component. However, the atypical intraductal component exhibited focal nuclear atypia, a cribriform pattern, and moderate to strong membranous human epidermal growth factor receptor 2 (HER2) immunoreactivity. HER2 amplification was detected in focal regions of the atypical intraductal component by fluorescence in situ hybridization (FISH), which resulted in a diagnosis of AME with ductal carcinoma in situ. OUTCOMES: The patient did not receive further therapy and was free from tumor recurrence at 23 months after the operation. CONCLUSION: HER2 FISH might be useful for evaluating suspected AME tumors for malignancy when an atypical ductal lesion that lacks definitive features of malignancy is encountered.

AIMS: Proliferative activity, evaluated from the Ki-67 index, is a strong prognostic factor in lung adenocarcinoma (LADC). Here, we optimized a procedure to measure the Ki-67 index and establish the best cut-off value. METHODS AND RESULTS: We examined 342 LADCs at stage I for the immunohistochemical expression of Ki-67 using different antibodies, MIB1 and SP6. The results revealed the superior specificity of SP6; therefore, SP6 was used in subsequent analyses. Slides were scanned with a virtual slide system. Using software, tumor cells were counted in a whole tumor. Thereafter, the tumor was evenly subdivided into 0.25-mm2 tiles. The frequency of positive cells was counted in each tile of an invasive area or the whole tumor. We calculated the number of tumor cells required to produce a 95% confidential interval (CI) <0.05. Additionally, we calculated coverage probabilities (CP) using two different methods, counting any number or 200 cells per tile. The results showed that we could meet our goal by counting 2000 cells from 10 random tiles (200 cells each) in invasive areas. CONCLUSIONS: We successfully developed an optimal procedure using an SP6 antibody, which provided CP >70% and CI of <0.05 in more than 90% of cases. Furthermore, we identified an optimal cut-off value of 0.12 with an alternative of 0.15, based on disease recurrence. This procedure and the cut-off values may be used in the routine pathological diagnosis of LADC.

Background Nonalcoholic steatohepatitis (NASH) is diagnosed with histopathologic testing, but noninvasive surrogate markers are desirable for screening patients who are at high risk of NASH. Purpose To investigate the diagnostic performance of dispersion slope, attenuation coefficient, and shear-wave speed measurements obtained using two-dimensional (2D) shear-wave elastography (SWE) in assessing inflammation, steatosis, and fibrosis and in the noninvasive diagnosis of NASH in patients suspected of having nonalcoholic fatty liver disease (NAFLD). Materials and Methods This prospective study collected data from 120 consecutive adults who underwent liver biopsy for suspected NAFLD and were enrolled between April 2017 and March 2019. Three US parameters (dispersion slope [(m/sec)/kHz], attenuation coefficient [dB/cm/MHz], and shear-wave speed [in meters per second]) were measured using a 2D SWE system immediately before biopsy. The biopsy specimens were scored by one expert pathologist according to the Nonalcoholic Steatohepatitis Clinical Research Network criteria (119 participants underwent a histologic examination). Diagnostic performance was assessed using the area under the receiver operating characteristic curve (AUC) for the categories of inflammation, steatosis, and fibrosis. Results One hundred eleven adults (mean age, 53 years ± 18 [standard deviation]; 57 men) underwent a US examination. Dispersion slope enabled the identification of lobular inflammation, with an AUC of 0.95 (95% confidence interval [CI]: 0.91, 0.10) for an inflammation grade greater than or equal to A1 (mild), 0.81 (95% CI: 0.72, 0.89) for an inflammation grade greater than or equal to A2 (moderate), and 0.85 (95% CI: 0.74, 0.97) for an inflammation grade equal to A3 (marked). Attenuation coefficient enabled the identification of steatosis, with an AUC of 0.88 (95% CI: 0.80, 0.97) for steatosis grade greater than or equal to S1 (mild), 0.86 (95% CI: 0.79, 0.93) for steatosis grade greater than or equal to S2 (moderate), and 0.79 (95% CI: 0.68, 0.89) for steatosis grade equal to S3 (severe). Shear-wave speed enabled the identification of fibrosis, with an AUC of 0.79 (95% CI: 0.69, 0.88) for fibrosis stage greater than or equal to F1 (portal fibrosis), 0.88 (95% CI: 0.82, 0.94) for fibrosis stage greater than or equal to F2 (periportal fibrosis), 0.90 (95% CI: 0.84, 0.96) for fibrosis stage greater than or equal to F3 (septal fibrosis), and 0.95 (95% CI: 0.91, 0.99) for fibrosis stage equal to F4 (cirrhosis). The combination of dispersion slope, attenuation coefficient, and shear-wave speed showed an AUC of 0.81 (95% CI: 0.71, 0.91) for the diagnosis of NASH. Conclusion Dispersion slope, attenuation coefficient, and shear-wave speed were found to be useful for assessing lobular inflammation, steatosis, and fibrosis, respectively, in participants with biopsy-proven nonalcoholic fatty liver disease. © RSNA, 2020 Online supplemental material is available for this article.

We encountered a patient with multiple myeloma treated with autologous hematopoietic stem cell transplantation (HSCT) who developed repeated episodes of enteritis but regressed spontaneously. An endoscopic examination revealed no abnormalities, but biopsy specimens showed massive infiltration of CD4+ and EBER+ abnormal lymphocytes in which a high copy number of Epstein Barr virus (EBV) genomes was detected by quantitative polymerase chain reaction (qPCR). EBV infection was exclusively detected in CD4+ T-cells, leading to a diagnosis of EBV-positive CD4+ T-cell LPD. This case suggests that an immediate biopsy and examinations, including qPCR for EBV DNA, should be considered for patients with recurrent enteritis after autologous HSCT, regardless of endoscopic findings.

BACKGROUND: Capicua transcriptional repressor (CIC) -rearranged sarcoma is characterized by small round cells, histologically similar to Ewing sarcoma. However, CIC-rearranged sarcoma has different clinical, histological, and immunohistochemical features from Ewing sarcoma. It is important to differentiate between these tumors. CASE PRESENTATION: The patient is a 44-year-old man with a duodenal tumor diagnosed in another hospital who presented with a history of melena. Laboratory studies showed anemia with a serum hemoglobin of 6.0 g/dL. He was hospitalized and gastrointestinal bleeding was controlled successfully with endoscopy. However, he suffered from appetite loss and vomiting and progression of anemia a few weeks after presentation. Upper gastrointestinal endoscopy showed a circumferential soft tumor in the second portion of the duodenum and the endoscope could not pass distally. Computed tomography scan showed a greater than 10 cm tumor in the duodenum, with compression of the inferior vena cava and infiltrating the ascending colon. A definitive pathologic diagnosis could not be established despite four biopsies from the tumor edge. Due to gastrointestinal obstruction and progression of anemia, a pylorus-preserving pancreaticoduodenectomy with partial resection of the inferior vena cava and right hemicolectomy was performed as a complete tumor resection. The tumor was diagnosed as a CIC-rearranged sarcoma, but 2 months postoperatively local recurrence and distant metastases to the liver and lung were found. The patient died 3 months after surgery. CONCLUSIONS: Although the only definitive treatment for CIC-rearranged sarcoma is surgical resection, the CIC-rearranged sarcoma is highly malignant with a poor prognosis even after radical resection. More research is needed to establish optimal treatment strategies.

Shear wave (SW) dispersion imaging is a newly developed imaging technology for assessing the dispersion slope of SWs, which is related to tissue viscosity in diffuse liver disease. Our preclinical and preliminary clinical studies have shown that SW speed is more useful than dispersion slope for predicting the degree of fibrosis and that dispersion slope is more useful than SW speed for predicting the degree of necroinflammation. Thus, dispersion slope, which reflects viscosity, may provide additional pathophysiological insight into diffuse liver disease.

RATIONALE: Primary carcinosarcoma of the upper urinary tract is rare. Ureteral duplication is one of the most common urinary tract malformations. Additionally, the association between ureteral duplication and malignancy is unknown. To the best of our knowledge, no cases of malignant tumors diagnosed as carcinosarcoma with ureteral duplication have been reported. We herein report the case of a patient with carcinosarcoma of the ureteropelvic junction associated with incomplete ureteral duplication. PATIENT CONCERNS: A 60-year-old Japanese woman presented with painless gross hematuria. She had a history of total hysterectomy and chemotherapy for endometrioid carcinoma 5 years before. She had no history of occupational chemical exposure. DIAGNOSES: Radiographic imaging revealed right incomplete ureteral duplication, hydronephrosis, and a polypoid tumor in the ureteropelvic junction of the lower moiety of the right kidney. Urine cytology showed a small amount of degenerated atypical epithelial and nonepithelial cells. The transureteral biopsy specimen showed dysplastic urothelial cells and atypical myoid spindle cells. These findings were indefinite for malignancy. INTERVENTIONS: The patient underwent right nephroureterectomy. Pathological examination of the resected tumor showed a biphasic neoplasm composed of carcinomatous and sarcomatous components. The sarcomatous component was immunohistochemically positive for vimentin, desmin, h-caldesmon, and α-SMA and negative for pancytokeratin (AE1/AE3), low molecular weight cytokeratin (CAM 5.2), EMA, E-cadherin, GATA3, uroplakin 2, and p63. Based on these findings, we diagnosed the tumor as carcinosarcoma. OUTCOMES: The postoperative course was uneventful. No additional therapy was administered. The patient has remained alive without recurrence for 21 months since surgery. LESSONS: Carcinosarcoma can arise from ureteral duplication. Although the majority of carcinosarcomas of the upper urinary tract are diagnosed at an advanced stage and have a poor prognosis, some can have a less aggressive course. Further studies are needed to determine the association between ureteral duplication and malignancy.

口腔領域の細胞診は、ブラシや綿棒などで粘膜を擦過して細胞を採取するので、侵襲性が少なく、繰り返し実施可能である。そのため、口腔癌検診や初診時のスクリーニング目的に実施されることが多い。口腔粘膜疾患細胞診の判定区分について解説し、口腔潜在的悪性疾患(紅板症、白板症、口腔扁平苔癬)、口腔上皮性異形成、扁平上皮癌(上皮内癌含む)における病理学的および細胞学的な項目を中心に概説した。