Publications by authors named "Michio Shimizu"

Follicular pancreatitis (FP) is characterized by nodular mass composed of lymphoid hyperplasia and fibrosis. We here present radiological and pathological features of three cases of FP. The three patients were middle- or old-aged men, and nodular mass was pointed out at health examination.

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Objective: The grading and typing of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas are challenging for pathologists. We aimed to clarify the points of consistency and disagreement in assessing the grades and types of IPMNs.

Methods: Digital slide images of 20 IPMNs were independently assessed by 10 Japanese pathologists, who then held a consensus meeting to discuss the points of disagreement and develop a consensus and recommendations.

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Objective: The aim of this study was to evaluate the clinicopathological features of solid pseudopapillary neoplasms (SPNs).

Methods: In this retrospective study, 288 SPNs were analyzed.

Results: Overall, 214 patients (74%) were female.

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Background: Medullary carcinoma of the pancreas (MCP) is a rare malignant pancreatic tumor. The World Health Organization classification defines the tumor as a subtype of pancreatic ductal carcinomas. MCP is histologically characterized as having highly pleomorphic cells with syncytial morphology, expansive tumor growth, and necrosis.

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Pancreatic masses consisting of lipomatous components clinically include lipoma, liposarcoma, lipomatous pseudohypertrophy of the pancreas, fat-containing neoplasms such as perivascular epithelioid cell tumor, and malignant neoplasm with lipoid degeneration. We present pancreatic lipomatous hamartoma, which has not been reported hitherto. A solid pancreatic mass was detected from a computed tomographic scan check-up in each of 3 cases of Japanese men.

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High-grade pancreatic intraepithelial neoplasia (HG-PanIN) is the major precursor of pancreatic ductal adenocarcinoma (PDAC) and is an ideal target for early detection. To characterize pure HG-PanIN, we analysed 23 isolated HG-PanIN lesions occurring in the absence of PDAC. Whole-exome sequencing of five of these HG-PanIN lesions revealed a median of 33 somatic mutations per lesion, with a total of 318 mutated genes.

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Intraductal tubulopapillary neoplasm (ITPN) is a relatively recently described member of the pancreatic intraductal neoplasm family. Thus, the literature on its histologic and immunohistochemical features, clinical behavior, and its similarities and differences from other pancreatic neoplasms is limited. Thirty-three cases of ITPN, the largest series to date, were identified.

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Article Synopsis
  • Malignant granular cell tumors (MGCTs) are very rare with limited research, and this study aims to explore their characteristics and prognostic factors.
  • The study analyzed 18 cases of MGCTs with a focus on diagnostics, survival rates, and the impact of factors like necrosis on patient outcomes.
  • Findings showed high recurrence and metastasis rates, even among atypical cases, indicating that both types require careful monitoring for better diagnosis and treatment strategies.
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International experts met to discuss recent advances and to revise the 2004 recommendations for assessing and reporting precursor lesions to invasive carcinomas of the pancreas, including pancreatic intraepithelial neoplasia (PanIN), intraductal papillary mucinous neoplasm (IPMN), mucinous cystic neoplasm, and other lesions. Consensus recommendations include the following: (1) To improve concordance and to align with practical consequences, a 2-tiered system (low vs. high grade) is proposed for all precursor lesions, with the provision that the current PanIN-2 and neoplasms with intermediate-grade dysplasia now be categorized as low grade.

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We previously reported that the number of mitotic and apoptotic figures in tumor cells in blood vessel tumor emboli had the greatest significant power for the accurate prediction of the outcome of patients with invasive ductal carcinoma of the breast. The purpose of the present study was to devise a grading system for blood vessel tumor emboli based on the mitotic and apoptotic figures of tumor cells in blood vessel tumor emboli, enabling accurate prediction of the outcome of patients with invasive ductal carcinoma of the breast. We classified 263 invasive ductal carcinomas into the following 3 grades according to the numbers of mitotic and apoptotic figures in tumor cells located in blood vessels within 1 high-power field: grade 0, no blood vessel invasion; grade 1, absence of mitotic figures and presence of any number of apoptotic figures, or 1 mitotic figure and 0 to 2 apoptotic figures; and grade 2, 1 mitotic figure and 3 or more apoptotic figures, or 2 or more mitotic figures and 1 or more apoptotic figures.

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Acinar cell carcinoma of the pancreas is a rare tumor with a poor prognosis. Compared to pancreatic ductal adenocarcinoma, its molecular features are poorly known. We studied a total of 11 acinar cell carcinomas, including 3 by exome and 4 by target sequencing.

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Background: Blue nevus is a benign dermal melanocyte tumor that mainly arises from the skin. We report an extremely rare case of blue nevus in a pediatric patient with extensive progression from the middle ear and inner ear to the nasopharynx through the Eustachian tube.

Case Report: A 2-year-old girl with blue tympanum was referred to our department.

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We present three cases of melanotic oncocytic metaplasia of the nasopharynx. Case 1 and Case 2 were a 70- and a 61-year-old woman, and Case 3 was a 74-year-old man. Although Case 1 was asymptomatic, Cases 2 and 3 had hoarseness.

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Background. Since gastrointestinal stromal tumor (GIST) is a mesenchymal submucosal tumor, the endosonographic, CT, and MRI features of gastric GISTs have been widely investigated. However, the GIST-bearing gastric mucosa status has not been reported.

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We reviewed the clinicopathological findings of eight cases of sessile serrated adenoma/polyps (SSA/Ps) with carcinoma, the largest diameter of which was 10 mm or less. All lesions were polyps located in the right side of the colon. Four lesions showed submucosal invasion and one lesion invaded the proper muscle layer.

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We report the case of a 78-year-old man with multiple bone tumours and three round, smooth nodules in the right lung. He was referred to our hospital because of the left femoral neck pathological fracture. The histological characteristics of the femoral tumour corresponded to clear cell carcinoma, and bone and lung lesions were regarded as metastatic from an unknown primary site, since there was no clinical evidence of renal carcinoma.

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This retrospective study investigated the clinicopathologic characteristics and clinical outcomes of esophageal basaloid squamous carcinoma (BSC). Among 190 patients with esophageal carcinoma treated surgically between 1998 and 2011, we identified 9 (4.7%) with BSC.

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Background And Aim: Endoscopic diagnosis of stomach mucosa-associated lymphoid tissue (MALT) lymphoma is often difficult because few specific findings are indicated. Even when MALT lymphoma is suspected by endoscopy, it is still difficult to make a definitive diagnosis by biopsy because lymphoma cells sometimes distribute unevenly. We previously reported that a tree-like appearance (TLA) is a characteristic finding of MALT lymphoma by narrow-band imaging (NBI) magnifying endoscopy and it is valuable in the selection of an optimal biopsy site in MALT lymphoma.

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Although nephroblastoma is the commonest renal tumor of childhood, it is rare in adults. In cases of predominantly epithelial type occurring in adulthood, it might be difficult to distinguish it from papillary renal cell carcinoma and metanephric adenoma. Here, we report three cases of adult epithelial nephroblastoma in 24-, 76-, and 21-year-old females.

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