Kei Yabuki

CAMTA1 is a useful immunohistochemical marker for diagnosing epithelioid haemangioendothelioma

The diagnosis of epithelioid haemangioendothelioma (EHE) is usually straightforward, based on characteristic histological features. However, it is sometimes difficult to differentiate EHE from a variety of other tumours with epithelioid morphology. The WW domain‐containing transcription regulator 1–calmodulin‐binding transcription activator 1 (WWTR1–CAMTA1) fusion gene, resulting in the overexpression of CAMTA1, is demonstrated in approximately 90% of EHEs, and the yes‐associated protein 1–transcription factor E3 (YAP1–TFE3) fusion gene, associated with the strong and diffuse nuclear expression of TFE3, is present in another small subset of EHEs. The aim of our study was to examine CAMTA1 expression in EHEs and a variety of other tumours to evaluate its diagnostic utility, and to analyse TFE3 expression status in EHEs.

Lanthanum deposition in the gastrointestinal mucosa and regional lymph nodes in dialysis patients: Analysis of surgically excised specimens and review of the literature.

Lanthanum carbonate (LC) is one of the most potent phosphate binders currently used to reduce serum phosphate levels in dialysis patients with end-stage renal disease (ESRD). LC forms insoluble complexes with dietary phosphate that pass through the gastrointestinal (GI) tract with little absorption. GI lesions due to lanthanum deposition in biopsy specimens or those in endoscopic submucosal dissection (ESD) in dialysis patients have been recently identified. Here, we describe more detailed histopathological findings in the gastroduodenal mucosa and regional lymph nodes in three patients with gastric cancer. Three patients with ESRD, two elderly women and one man, underwent dialysis and were treated with LC for 3-36 months. The patients underwent laparoscopic distal gastrectomy and lymph node dissection due to gastric cancer. Many subepithelial histiocyte aggregates or small foreign body granulomas, which contained gray or brown pigments or crystal-like structures, were mostly present in non-neoplastic areas of the upper GI. Lanthanum accumulation was noted in the duodenal mucosa and the antral and body mucosae of the gastric lesser curvature. Lanthanum was also deposited in the regional lymph nodes of the three patients. Electron microscopy with energy dispersive X-ray spectroscopy confirmed lanthanum and phosphorus deposits in histiocytes. Long-term prognosis of patients and the excretion or the metabolic pathway of accumulated lanthanum remain unclear.

Risk factors for a prolonged operative time in a single-incision laparoscopic cholecystectomy

BACKGROUND A prolonged operative time is associated with adverse post-operative outcomes in laparoscopic surgery. Although a single-incision laparoscopic cholecystectomy (SILC) requires a longer operative time as compared with a conventional laparoscopic cholecystectomy, risk factors for a prolonged operative time in SILC remain unknown. METHODS A total of 20 clinical variables were retrospectively reviewed to identify factors for a prolonged operative time (longer than 3 h) in a total of 220 consecutive patients undergoing SILC. RESULTS The median operative time was 145 min (range, 55-435) and a prolonged operative time was required in 62 patients (28%). Independent factors that predict a prolonged operative time as identified through multivariate analysis were body mass index (BMI) (P = 0.009), acute cholecystitis (P < 0.001) and operator (resident or staff surgeon) (P < 0.001). Furthermore, a prolonged operative time was significantly associated with an increased amount of intra-operative blood loss (P < 0.001) and a prolonged stay after surgery (P < 0.001). CONCLUSIONS These findings suggest that a higher BMI, acute cholecystitis and a resident as an operator significantly increase the duration of SILC procedures.

Immunohistochemical and molecular detection of the expression of FGF23 in phosphaturic mesenchymal tumors including the non-phosphaturic variant

BackgroundPhosphaturic mesenchymal tumors (PMTs) are rare neoplasms that are often associated with tumor-induced osteomalacia (TIO) due to excessive serum levels of fibroblast growth factor 23 (FGF23). PMTs share overlapping histologic features with other types of tumors; thus, accurate pathological diagnosis may be challenging. We performed an immunohistochemical examination of FGF23 expression in PMTs and other types of tumors, together with pertinent molecular analyses.MethodsSeven PMTs (5 with TIO and 2 without TIO) and 46 other types of bone and soft tissue tumors were retrieved, and immunohistochemistry was performed using a commercially available anti-FGF23 antibody. In addition, FGF23 mRNA expression was detected by reverse transcription-polymerase chain reaction (RT-PCR), using RNA extracted from formalin-fixed, paraffin-embedded tissues.ResultsImmunohistochemical analysis of FGF23 expression showed distinct, punctate staining in the cytoplasm in 5 PMTs with TIO, whereas FGF23 expression was negative in the 2 PMTs without TIO and the other 46 tumors. FGF23 mRNA expression was detected in all 4 PMTs examined, as well as in 1 chondromyxoid fibroma and 1 myxoid liposarcoma. The real-time RT-PCR data showed that the relative expression levels of the FGF23 mRNA tended to be higher in PMTs with TIO than in PMTs without TIO, or in the chondromyxoid fibroma specimen.ConclusionsOur data suggested that the feasibility of immunohistochemical detection of FGF23 may depend on the level of secreted FGF23 from tumor cells. Thus, immunohistochemistry for FGF23 is an useful diagnostic adjunct for PMT, although its utility appears to be limited in cases without TIO.

Stapled gastro/duodenojejunostomy shortens reconstruction time during pylorus-preserving pancreaticoduodenectomy

AIM To investigate whether a stapled technique is superior to the conventional hand-sewn technique for gastro/duodenojejunostomy during pylorus-preserving pancreaticoduodenectomy (PpPD). METHODS In October 2010, we introduced a mechanical anastomotic technique of gastro- or duodenojejunostomy using staplers during PpPD. We compared clinical outcomes between 19 patients who underwent PpPD with a stapled gastro/duodenojejunostomy (stapled anastomosis group) and 19 patients who underwent PpPD with a conventional hand-sewn duodenojejunostomy (hand-sewn anastomosis group). RESULTS The time required for reconstruction was significantly shorter in the stapled anastomosis group than in the hand-sewn anastomosis group (186.0 ± 29.4 min vs 219.7 ± 50.0 min, P = 0.02). In addition, intraoperative blood loss was significantly less (391.0 ± 212.0 mL vs 647.1 ± 482.1 mL, P = 0.03) and the time to oral intake was significantly shorter (5.4 ± 1.7 d vs 11.3 ± 7.9 d, P = 0.002) in the stapled anastomosis group than in the hand-sewn anastomosis group. There were no differences in the incidences of delayed gastric emptying and other postoperative complications between the groups. CONCLUSION These results suggest that stapled gastro/duodenojejunostomy shortens reconstruction time during PpPD without affecting the incidence of delayed gastric emptying.

Bullous Pemphigoid Associated with the Dipeptidyl Peptidase-4 Inhibitor Sitagliptin in a Patient with Liver Cirrhosis Complicated with Rapidly Progressive Hepatocellular Carcinoma

A 78-year-old man presented with cutaneous blisters of the limbs and abdominal distension. He had been treated for various diseases, including liver cirrhosis. He had begun receiving sitagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, for diabetes mellitus three years before the hospitalization. A skin biopsy demonstrated bullous pemphigoid. Ultrasonography (US) revealed multiple liver tumors, although he had been receiving regular US studies. We stopped sitagliptin and started insulin and corticosteroids. However, his renal dysfunction progressed, and he died 14 days after the hospitalization. We should therefore be careful of various complications, including bullous pemphigoid and progression of tumors, when using DPP-4 inhibitors.

A unique case of a huge mixed squamous cell and glandular papilloma of non-endobronchial origin with a peripheral growth

We report a case of a huge solitary non-endobronchial pulmonary tumor in a 76-year-old male smoker. The tumor measured 11 × 10 × 8 cm. It was ill-defined, and it was located periphery of the right lower lobe with the subpleural cystic spaces. He underwent right lower lobectomy with mediastinal lymph node dissection and is free from tumor 30 months after surgery. Microscopically, it was composed of a proliferation of squamous and ciliated columnar epithelial cells with a few mucous cells. These cells were arranged in a papillary growth fashion extending along the fibrously thickened alveolar septa together with metaplastic bronchiolar and squamous epithelia displaying an usual interstitial pneumonia-pattern. Although the histologic features of the tumor were that of a mixed squamous cell and glandular papilloma (MSCGP), it was peripherally located and showed a lepidic growth, and it was much larger than previously reported MSCGPs. It is possible that the tumor developed in association with bronchial metaplasia in the periphery of the lung, and then extended along the surface of the reconstructed air spaces, which resulted in its unique histologic appearance. Further investigations of respiratory papilloma are needed to clarify the pathogenesis of these lesions.

Inhibition of WNT/β-catenin signaling under serum starvation and hypoxia induces adipocytic transdifferentiation in human leiomyoma cells

Fatty metamorphosis is an uncommon alteration in uterine leiomyoma (i.e., lipoleiomyoma), and the pathogenetic mechanisms underlying this phenomenon remain poorly understood. Because a conditional deletion of β-catenin, a major transducer of the canonical Wingless/integrated (WNT) pathway, in the developing mouse uterus can induce adipogenesis in the myometrium, it is hypothesized that inhibition of the WNT/β-catenin signaling may be also involved in the development of fat cells within uterine leiomyoma. In the current study, which was performed to address this point, intracytoplasmic lipid droplets were detectable in cultured human leiomyoma cells by treatment with a potent tankyrase inhibitor, XAV939, which antagonizes β-catenin, in a serum-starved culture medium without additional adipogenesis-inducing agents or supplements, and showed increasing accumulation in a time-dependent manner. In addition, the induction of fat cells was greatly enhanced under hypoxic conditions (i.e., 2.5% O2)—recapitulating the local in vivo situation of uterine leiomyoma—in comparison to that under normoxic conditions (i.e., 21% O2). The marker genes of differentiated fat cells such as ADIPOQ and PLIN were highly expressed in leiomyoma cells that were treated with XAV939 under hypoxia and serum starvation, whereas the immunohistochemical expression of desmin—a cytoskeletal protein representing smooth muscle differentiation—was downregulated, which appears in line with the switch in differentiation. The results of our study suggest that the inhibition of canonical WNT/β-catenin signaling under the stress due to hypoxia and serum starvation can initiate adipocytic transdifferentiation or metaplasia in human uterine leiomyoma cells, which is potentially related to the development of lipoleiomyoma.

甲状腺の胸腺様分化を示す癌Carcinoma Showing Thymus-Like Differentiation（CASTLE）of the Thyroidの１例

The case presented herein was a 70-year-old woman who had no compliant, but had a mass in the lower part of the right lobe of the thyroid detected by ultrasound (US). The US image of the tumor, measuring 13 mm in diameter, showed a low and heterogeneous internal echo level with calcification and an irregular margin. The tumor appeared to extend to the adjacent sternothyroid muscle, and cervical lymph node swelling was detected in a computer tomography (CT) image, but no metastatic lesion was found by positron emission tomography (PET)-CT. In a fine needle aspiration cytology of the tumor, papillary thyroid carcinoma was suggested because of the atypical epithelial cells having some changes other than intranuclear inclusion bodies. A subtotal thyroidectomy and central neck lymph node dissection were performed. The excised tumor was histologically composed of irregular nests or sheets of atypical squamoid epithelial cells with some ductal structures that leached to the sternothyroid muscle and involved the right lower parathyroid gland. Carcinoma showing thymus-like differentiation (CASTLE) was diagnosed histopathologically and immunohistochemically with the following immunohistochemical results: Cluster of differentiation 5 (CD5) (+), tumor protein p63 (p63) (+), KIT proto-oncogene receptor tyrosine kinase (c-KIT(CD117)) (+), thyroglobulin (-), and thyroid transcription factor-1 (TTF-1) (-). CASTLE is a rare carcinoma of the thyroid that architecturally resembles thymic epithelial tumors. Many CASTLE patients have been misdiagnosed as other carcinomas, such as anaplastic carcinoma, poorly differentiated carcinoma or squamous cell carcinoma of the thyroid. Immunohistochemical examination, including CD5 played an important role in the final diagnosis of CASTLE, although the distinction from diagnosis as squamous cell carcinoma or mucoepidermoid carcinoma in Hematoxylin-Eosin staining was challenging in our case. Nodal metastasis and perithyroidal tumor extension of CASTLE can predict its worse prognosis. Thus, at least careful follow-up studies are mandatory in cases of CASTLE.

Sclerosing Mucoepidermoid Carcinoma in the Parotid Gland With CRTC1-MAML2 Fusion: A Case Report:

In this article, we report a case of sclerosing mucoepidermoid carcinoma (MEC) arising in the parotid gland, with CRTC1-MAML2 gene fusion. A 73-year-old woman with a mass in the right parotid region was referred to our hospital. Radiological imaging tests revealed a well-defined mass, measuring 25 mm in diameter, with foci of calcification in the deep lobe of the parotid gland, extending to the parapharyngeal space. Microscopically, the tumor was composed of a proliferation of atypical glandular epithelial cells having intracytoplasmic mucin, squamoid cells, and intermediate cells arranged in nests embedded in a fibrosclerotic stroma, associated with a dense chronic inflammatory infiltrate containing immunoglobulin G4-immunoreactive plasma cells. Reverse transcription-polymerase chain reaction analysis using a formalin-fixed, paraffin-embedded tumor tissue specimen revealed the CRTC1-MAML2 fusion gene transcript. This is the first report of sclerosing MEC with the detection of the MEC-associated fusion gene, reinforcing a common genetic association between MEC and sclerosing MEC.