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Featured researches published by Yoshiaki Imamura.


Surgery Today | 2003

Primary Hepatic Neuroendocrine Carcinoma Coexisting with Hepatocellular Carcinoma in Hepatitis C Liver Cirrhosis: Report of a Case

Makoto Ishida; Kenichiro Seki; Atushi Tatsuzawa; Kanji Katayama; Kazuo Hirose; Takeshi Azuma; Yoshiaki Imamura; Ajit Abraham; Akio Yamaguchi

Abstract.Primary hepatic neuroendocrine carcinoma is an extremely rare tumor of the liver. We herein describe a case of primary hepatic neuroendocrine carcinoma with lymph node metastases, coexisting with hepatocellular carcinoma, on a background of hepatitis C cirrrhosis, in a 72-year-old man. Abdominal ultrasonography and computed tomography (CT) showed a tumor (3 cm in diameter) in Couinauds hepatic segment 8 (S8) with regional lymph node metastases. Whole-body CT, magnetic resonance imaging (MRI), and endoscopy did not reveal primary lesions outside the liver. Feridex MRI and [18F]fluorodeoxyglucose positron emission tomography were strongly suspicious of malignancy. A limited hepatectomy with regional lymph node dissection was performed. Histopathology, immunohistochemistry, and electron microscopy confirmed a diagnosis of primary neuroendocrine carcinoma on a background of liver cirrhosis. A tumor (1.5 cm in diameter) found in hepatic S5 at operation was also simultaneously resected, and histologically diagnosed to be hepatocellular carcinoma. We also review previous reports of hepatic neuroendocrine carcinoma and discuss hypotheses for the histogenesis of these tumors as well as prognostic implications. Given the background cirrhosis and coexisting hepatocellular carcinoma, we speculate that one of the hepatocellular carcinomas underwent neuroendocrine differentiation.


European Journal of Histochemistry | 2009

Prognostic factors affecting disease-free survival rate following surgical resection of primary breast cancer.

K Horita; A Yamaguchi; K Hirose; M Ishida; Sakon Noriki; Yoshiaki Imamura; Masaru Fukuda

In order to identify the prognostic factors that significantly influence the disease-free survival rate after surgical resection of primary breast cancers, we determined tumour and lymph node grades, and immunohistochemical staining for estrogen and progesterone receptors (ER and PR), c-erbB-2, p53, bcl-2, bax and PCNA in 76 patients. Univariate analysis showed that increased grade of tumour and lymph nodes, negative immunostaining for ER, positive immunostaining for c-erbB-2, and a high PCNA index (> or = 30%) negatively influenced the disease-free survival rate, but PR, p53, bcl-2 and bax had no predictive value. Although p53 was not an independent prognostic factor by itself, the combination of p53, bcl-2, and bax proved to correlate with the disease-free survival, with the best prognosis noted in tumours negative for p53 and positive for both bcl-2 and bax, intermediate prognosis in tumours negative for p53 and positive for either bcl-2 or bax and worst prognosis in tumors negative for p53 as well as bcl-2 and bax. Tumour grade correlated positively with PCNA index, while positive staining for ER correlated negatively with tumour grade as well as with PCNA index, although this was statistically insignificant. Immunostaining of breast cancers for bcl-2 correlated negatively with tumour grade and PCNA index. Immunostaining for c-erbB-2 correlated positively with PCNA but not with tumour grade. Immunostaining for p53 tended to correlate positively with PCNA, but not with tumour grade. Immunostaining for PR and bax did not correlate with tumour grade and PCNA index. These results suggest that in addition to tumour size and lymph node involvement, immunostaining for ER, c-erbB-2, and a high PCNA index are important prognostic factors in human breast cancer. Wild-type p53 with preserved bcl-2 and bax gene products is also a favorable prognostic factor indicating breast cancer at an early stage of cancer progression.


Pathology International | 2003

Leiomyomatosis peritonealis disseminata with malignant change in a man

Tadanori Yamaguchi; Yoshiaki Imamura; Tatsuya Yamamoto; Masaru Fukuda

Leiomyomatosis peritonealis disseminata (LPD) is a rare clinicopathological entity typically observed in women of reproductive age. We report a case of LPD with malignant change in a man. A 77‐year‐old man presented with a mass measuring 10 cm in diameter at the terminal ileum and numerous peritoneal small nodules that were revealed by abdominal computed tomography. Right hemicolectomy with lymph node dissection was performed. Macroscopically, a tumor of the terminal ileum consisted of aggregates of small nodular lesions with calcification and necrosis. The wall of the ileum and colon was intact. Microscopically, some of the nodular lesions consisted of neoplastic growths of atypical spindle cells with cellular atypism and abnormal mitoses. A few of these lesions were completely surrounded by smooth muscle bundles. Hemorrhages and necroses were found within the tumor nodules. Immunohistochemically, the tumor cells were positive for vimentin, desmin, muscle actin, α‐smooth muscle actin, cytokeratin and p53. The remaining nodular lesions, including small peritoneal lesions, were composed of hypocellular hyalinizing nodules. This case was thought to be LPD with malignant change, although the pathogenesis was uncertain because the tumor cells were negative for estrogen and progesterone receptors.


Journal of Gastroenterology | 2002

Intraductal mucinous tumors occurring simultaneously in the liver and pancreas

Makoto Ishida; Kenichiro Seki; Kei Honda; Toshihisa Kimura; Kanji Katayama; Kazuo Hirose; Manabu Dojo; Takeshi Azuma; Yoshiaki Imamura; Robert R. Hutchins; Akio Yamaguchi

A case of simultaneous intraductal mucinous tumors of the liver and pancreas in a 67-year-old man is described. Abdominal ultrasonography and computed tomography (CT) revealed the presence of cystic lesions with intraluminal septae both in the caudate lobe of the liver and in the uncinate process of the pancreas; these cystic lesions communicated with the hepatic duct and pancreatic duct, respectively. Mucin retention was observed in the cysts, and cholestasis was induced by mucin secretion into the common bile duct. The lesions were resected by left hepatic lobectomy with caudate lobectomy, and segmental pancreatectomy. Both lesions were multilocular cystic tumors with no papillary projections or focal mass effect in their walls. Histologically, both cystic lesions were a mixture of hyperplasia and adenoma lined by low papillary columnar epithelium. There were no cellular or histological features to suggest malignant change. The fibrous intratumor interstitium lacked any mesenchymal or ovarian-like stroma. The hepatic lesion was considered to be of a similar nature to intraductal papillary mucinous tumor (IPMT) of the pancreas. However, the two lesions occurred simultaneously in the liver and pancreas. This case is of interest in regard to the diagnosis and management of mucinous hepatopancreatobiliary lesions.


Acta Cytologica | 2004

Sclerosing polycystic adenosis of the left parotid gland: report of a case with fine needle aspiration cytology.

Yoshiaki Imamura; Tetsuo Morishita; Masaru Kawakami; Gota Tsuda; Masaru Fukuda

BACKGROUND Sclerosing polycystic adenosis (SPCA) of major salivary glands is a rare recently described entity. We report a case of SPCA of the left parotid gland, including the cytologic and histopathologic findings. CASE A 20-year-old man presented with a left parotid mass that had been growing slowly for 3 years. Fine needle aspiration cytology showed many syncytial cell clusters of variable size and some ductal structures with an inflammatory background. The cells forming syncytial clusters were large and polygonal, with abundant, eosinophilic, granular or lacelike cytoplasm. Apocrine differentiation with decapitation secretion was commonly seen. The ductal cells had a relatively high nuclear/cytoplasmic ratio, with granular cytoplasm. Grossly, the 5-cm lesion was a discrete, pale, cystic nodule embedded within the parotid gland parenchyma. Microscopically, the lesion was a nonencapsulated, circumscribed mass of sclerotic and hyalinized, collagenous tissue with lymphoplasmacytic infiltration. Sclerosing adenosis and cystic ducts with frequent apocrinelike cells were commonly seen. Some acinar cells contained eosinophilic, intracytoplasmic granules of various sizes. CONCLUSION The presence of syncytial clusters with apocrine metaplasia and ductal structures in a lymphoplasmacytic background should suggest a diagnosis of SPCA of a major salivary gland.


Clinical Nuclear Medicine | 2011

Kikuchi-Fujimoto disease: PET/CT assessment of a rare cause of cervical lymphadenopathy.

Tetsuya Tsujikawa; Tatsuro Tsuchida; Yoshiaki Imamura; Masato Kobayashi; Satoko Asahi; Kazuhiro Shimizu; Kazunobu Tsuji; Hidehiko Okazawa; Hirohiko Kimura

Purpose: Kikuchi-Fujimoto disease (KFD), formerly called subacute necrotizing lymphadenitis, is a rare cause of cervical lymphadenopathy. The purpose of this study was to evaluate the usefulness of FDG PET/CT for distinguishing KFD from non-Hodgkin lymphoma (NHL). Materials and Methods: Twenty-two patients with cervical lymphadenopathy (8 with KFD and 14 with NHL) underwent CT and FDG PET/CT scans to examine the cervical lymphadenopathy. Regional values of FDG uptake were evaluated using the standardized uptake value (SUV) and partial volume corrected SUV (corSUV) based on the count recovery coefficient. Tumor size (mm), SUV, and corSUV were compared among KFD, indolent NHL, and aggressive NHL. Results: KFD lesions tended to be smaller (13.8 ± 5.4 mm) than those of indolent (25.4 ± 11.8) and aggressive (29.7 ± 18.8) NHL, whereas there were no significant differences in size. As for SUV, a significant difference was observed only between indolent and aggressive (6.4 ± 1.5 and 17.3 ± 9.3, P < 0.05) NHL; however, KFD showed a significantly greater corSUV (23.8 ± 10.6) as compared with indolent NHL (9.2 ± 5.1, P < 0.05), which did not show a significant difference from aggressive NHL (21.4 ± 10.2). FDG PET/CT detected thoracoabdominal lesions in 2 patients (25%) with KFD. Conclusions: KFD shows high FDG uptake for size, which may reflect the pathologic characteristics, including necrotizing lymphocytes and numerous histiocytes (macrophages) surrounding small necrotic foci. FDG PET/CT will be useful for detecting noncervical lesions of KFD and distinguishing KFD from NHLs using both SUV and corSUV.


American Journal of Physiology-regulatory Integrative and Comparative Physiology | 2008

Long-lasting breaches in the bladder epithelium lead to storage dysfunction with increase in bladder PGE2 levels in the rat

Rikiya Shioyama; Yoshitaka Aoki; Hideaki Ito; Yosuke Matsuta; Keiko Nagase; Nobuyuki Oyama; Yoshiji Miwa; Hironobu Akino; Yoshiaki Imamura; Osamu Yokoyama

Increase in bladder mucosal permeability can be reproduced by intravesical administration of protamine sulfate (PS); however, the influence of PS once administered into the bladder disappears within several days. We developed a chronic animal model of urothelial injury using PS. Insertion of a polyethylene catheter through the bladder dome was performed in female Wistar rats. The other end of the catheter was connected to an osmotic pump for continuous delivery of PS or vehicle for 2 wk. Urinary frequency (UF) and voided volume (VV) were measured in the metabolic cage. The fifth group of rats received a high dose of PS (10 mg/ml) for 2 wk and were followed for a further 2 wk without PS. The sixth group received a high dose of PS for 2 wk and loxoprofen (0.1 mg.kg(-1).day(-1)) for 4 wk. UF was increased, and VV was reduced in rats treated with a high dose of PS but not changed in rats treated with a vehicle or a low dose of PS (1 mg/ml). UF was further increased in the fifth group, while unchanged in the sixth group. Histological sections in rats treated with a high dose of PS demonstrated a loss of the upper layer of urothelial cells and an increased number of mast cells. PGE2 level in the bladder was significantly elevated in the fifth group. These results indicate that chronic urotherial injury leads to an increase in UF and a decrease in VV. Increased PGE2 level in the bladder is likely to be associated with long-lasting storage dysfunction.


Journal of Dermatological Science | 2001

Expression of granulocyte colony-stimulating factor and its receptor in epithelial skin tumors

Koichiro Hirai; Masanobu Kumakiri; Shigeharu Fujieda; Hiroshi Sunaga; Li-Min Lao; Yoshiaki Imamura; Keiichi Ueda; Masaru Fukuda

Granulocyte colony-stimulating factor receptors (G-CSFR) have been observed on the surface of not only hematopoietic cells but also several cancer cells. In the present study, we investigated the expression of G-CSFR or G-CSF in epithelial skin tumors by immunohistochemical staining. The assessments were defined by the percentage of G-CSFR or G-CSF positive cells and expressed as G-CSFR and G-CSF scores. The G-CSFR score in SCC (77.6+/-20.0%) was significantly higher than that in Bowens disease (BD) (51.0+/-35.6%), actinic keratosis (AK) (49.3+/-34.6%) or normal skin (30.0+/-32.1%) (P=0.0004, P=0.0003, P<0.0001, respectively). The mean G-CSF score in SCC (56.7+/-27.4%) or in BD (44.1+/-31.4%) was higher than that in normal skin (24.9+/-25.8%) (P=0.0075, P<0.001, respectively). G-CSF expression in AK (29.8+/-31.2%) was lower than that in SCC (P=0.0037). There was significant positive correlation between the G-CSFR score and the G-CSF score (gamma=0.274, P=0.0107) in skin tumors. These findings suggested that the assessment of G-CSFR expression might be associated with carcinogenesis of skin tumors.


Clinical Imaging | 2004

A case of solid variant type of pancreatic serous cystadenoma mimicking islet cell tumor.

Tatsuya Yamamoto; Norio Takahashi; Tadanori Yamaguchi; Yoshiaki Imamura

We report a case of the solid variant type of pancreatic serous cystadenoma in which the very small size of the cyst on ultrasonography and computed tomography made distinguishing this tumor from other hypervascular solid tumors difficult. Recognizing the imaging features of high signal intensity on heavily T2-weighted image on MR may be helpful for correctly diagnosing the solid variant type of pancreatic serous cystadenoma.


Acta Cytologica | 2009

Imprint Cytologic Features in Renal Cell Carcinoma Associated with Xp11.2 Translocation/TFE3 Gene Fusion in an Adult: A Case Report

Tadanori Yamaguchi; Naoto Kuroda; Yoshiaki Imamura; Ondrej Hes; Takako Kawada; Keizou Nakayama

BACKGROUND Adult-onset renal cell carcinoma (RCC) associated with Xp11.2 translocation/TFE3 gene fusion is a very rare tumor. To date, there are no reports on immunocytochemical study of the primary tumor. We describe such a case that we diagnosed by immunocytochemistry of imprint cytology material. CASE A 46-year-old man was found to have a mass in the lower pole of the right kidney. Magnetic resonance imaging (MRI) T2-weighted images showed a hypointense area in the tumor, and papillary RCC was suspected. Imprint cytology showed tumor cells that were isolated or arranged in large or small papillary clusters. Irregularly shaped large oval nuclei, finely granular chromatin and a single large nucleolus were noted. Cytoplasm was abundant and admixed with clear and granular eosinophilic patterns and scattered large vacuolated cells. Almost all tumor cells diffusely expressed immunocytochemical reactivity to TFE3 protein. Hyaline nodules were observed in the stroma. Ultrastructurally, neoplastic cells contained rhomboid crystals identical to those of alveolar soft part sarcoma. CONCLUSION The immunocytochemistry of TFE3 protein may be a powerful tool for accurate diagnosis when RCC associated with Xp11.2 translocation/TFE3 gene fusion is suspected by imprint cytology even in adult-onset cases, and cytotechnologists should accurately recognize cytologic findings of this tumor.

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Hitoshi Saito

Kyoto Prefectural University of Medicine

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