Paratracheal Middle Mediastinal Thymic Carcinomas

We describe case studies of two patients who underwent resection of paratracheal middle mediastinal thymic carcinomas. In both patients, complete resection of these masses via right thoracotomy was performed using three-dimensional computed tomography. Final pathologic diagnoses were thymic squamous cell carcinoma and thymic atypical carcinoid tumor. Challenges and debates in preoperative, intraoperative, and postoperative management are discussed in this article.

P40 expression in small cell lung cancer: The presence of p40-positive cells does not always indicate squamous differentiation

Background

Small cell lung cancer (SCLC) is normally diagnosed with hematoxylin and eosin stains, although some cases require immunohistochemistry (IHC). P40 is highly sensitive and specific for squamous cell carcinoma and is thus considered the best marker for this cancer. However, the status of p40 expression in SCLC is not well known. The aim of this study was to analyze p40 expression in resected SCLC using IHC.

Methods

Forty‐four surgically resected SCLC cases were enrolled. Clinical data were obtained from the patients’ medical records. Pathologists blinded to the patients’ clinical data reviewed the SCLC slides. IHC was performed on a representative slide of each case.

Results

Although p40 was not diffusely expressed in any of the SCLC cases, p40‐positive cells were observed in the tumors in 15 cases (34.1%). Ten of these exhibited p40 in < 1% of tumor cells. In the remaining five cases, 1–5% of tumor cells expressed p40, and in three of these, the cells expressing p40 also expressed TTF‐1 and neuroendocrine markers. There was no statistically significant relationship between p40 positivity and any other clinicopathological characteristics.

Conclusions

Some resected SCLCs express p40 focally. This result suggests that the presence of positive p40 cells does not exclude a diagnosis of SCLC. Thus, small biopsy or cytology specimens with p40‐positive cells must be diagnosed carefully.

Development of novel force-limiting grasping forceps with a simple mechanism

OBJECTIVES

In endoscopic surgery, fragile tissues may be damaged by the application of excessive force. Thus, we developed novel endoscopic forceps with a simple force-limiting mechanism.

METHODS

The novel forceps were constructed with a leaf spring, and the spring thickness determines grasping pressure. We established an evaluation system (maximum score is 11 points) for lung tissue damage leading to complications. We tested the conventional forceps (186.8 kPa) and 3 novel spring forceps with the following thicknesses: 1.3 mm (53.0 kPa), 2.2 mm (187.7 kPa) and 2.8 mm (369.2 kPa). After grasping, peripheral canine lung tissues were microscopically examined for acute- and late-phase damages.

RESULTS

In the acute phase (20 sites), the novel forceps caused capillary congestion and haemorrhage in the subpleural tissue, whereas the conventional forceps caused deep tissue and pleural damages. In the late phase (30 sites), both forceps caused fibroblast formation and interstitial thickening, which progressed to the deeper tissues as grasping pressure increased. In the acute phase, the median scores were 2.0 and 6.0 for the novel and conventional forceps, respectively (P = 0.003). In the late phase, the median scores were 2.0, 2.5 and 5.0 for 1.3-, 2.2- and 2.8-mm thick forceps, respectively, and 5.0 for the conventional forceps (P < 0.001). In both phases, the novel forceps with grasping pressure set below 187.7 kPa (2.2 mm) caused significantly less lung tissue damage than the conventional forceps.

CONCLUSIONS

The novel endoscopic forceps are able to regulate the tissue-grasping pressure and induce less damage in lung tissues than conventional forceps.

A multichannel gated neutron detector with reduced afterpulse for low-yield neutron measurements in intense hard X-ray backgrounds

A design of multichannel gated photomultiplier tube (PMT) is presented for the 960-channel neutron time-of-flight detector at the Institute of Laser Engineering of Osaka University. This is important for the fusion science and the nuclear photonics where intense hard X-rays are generated from the interaction of ultra-short laser pulse of petawatt power density with matter. The hard X-rays often overload PMTs and cause signal-induced background noises called afterpulses, making the detection of subsequent neutrons impossible. For this reason, the PMTs are coupled with an electrical time-gating (ETG) system to avoid overloading. The ETG system disables the PMT by modulating the dynode potential during the primary X-ray flash. An after-pulsing suppression technique is demonstrated by applying a reverse bias voltage between the photocathode and the first dynode. The presented multichannel scheme provides a gate response time of 80 ns, a signal cutoff ratio of 2.5 × 10², and requires reasonably low power consumption.

Prevalence of Salmonella enterica Subspecies enterica in Red-Eared Sliders Trachemys scripta elegans Retailed in Pet Shops in Japan

We investigated the prevalence of Salmonella in 227 small red-eared sliders (Trachemys scripta elegans) from 2006 to 2008. A total of 130 turtles (57.3%) tested positive for S. enterica subsp. enterica. Twenty-two serotypes including S. Montevideo, S. Newport, S. Pomona, S. Braenderup, S. Sandiego, and S. Litchfield were identified. Salmonella strains with closely related pulsed field gel electrophoresis (PFGE) patterns were isolated from several shops located in different areas from 2006 to 2008. Antimicrobial resistance was detected among strains of S. Montevideo, S. Newport, S. Braenderup, S. Sandiego, and S. Litchfield. The relatedness of antimicrobial resistance and PFGE profiles was not observed. The PFGE patterns of S. Poona strains isolated in 2006 and 2008 and the causative strains of turtle-associated salmonellosis in 2006 were identical. These results revealed a high prevalence of Salmonella enterica subsp. enterica in red-eared sliders retailed in Japan. In addition, genetically closely-related strains of turtle-associated Salmonella were repeatedly introduced into Japan over the study period and were distributed widely in Japan. These Salmonella strains present a risk of a widely disseminated outbreak of turtle-associated salmonellosis.

GATA6-positive lung adenocarcinomas are associated with invasive mucinous adenocarcinoma morphology, hepatocyte nuclear factor 4α expression, and KRAS mutations

AIMS

GATA6 is known to play a role in lung development. However, its role in the carcinogenesis of lung cancer is not well studied. The aim of this study was to analyse GATA6 expression in lung adenocarcinomas (LAs) by immunohistochemistry (IHC) in order to define its association with clinicopathological characteristics.

METHODS AND RESULTS

IHC analysis of GATA6 was performed with tissue microarray slides containing 348 LAs. The association between GATA6 expression and clinicopathological parameters was evaluated. GATA6 expression in epithelial tumours other than lung cancer was also evaluated. GATA6 expression was found in 47 LAs (13.5%). This occurred more frequently in younger patients (P = 0.005), and was associated with the absence of lymph node metastasis (P =0.024), well-differentiated to moderately differentiated tumours (P < 0.001), the absence of lymphatic invasion (P = 0.020), and the absence of vascular invasion (P = 0.011). GATA6 expression was associated with mucin production (P < 0.001), the invasive mucinous adenocarcinoma subtype (P < 0.001), KRAS mutations (P = 0.026), expression of MUC2 (P < 0.001), CDX2 (P = 0.049), and MUC5AC (P < 0.001), and absence of expression of TTF-1 (P = 0.002). GATA6 expression was also associated with hepatocyte nuclear factor 4α (HNF4α) expression (P < 0.001). GATA6 expression tended to indicate better prognoses, whereas patients with HNF4α expression had significantly worse prognoses (P = 0.033). Of 270 tumours other than lung cancer, 110 expressed GATA6.

CONCLUSIONS

These findings suggest that GATA6 might interact with HNF4α and contribute to the development of mucinous-type LAs.

Full-layer mucosal histology in achalasia: Histological epithelial wave is characteristic in "pinstripe pattern"-positive achalasia

BACKGROUND

Previously, the mucosal histology in achalasia has only been investigated using superficial biopsy or surgically resected esophageal specimens in end-stage cases. We investigated the histology of the full-layer mucosa in early and advanced achalasia.

METHODS

Endoscopy was performed for the pinstripe pattern (PSP) (an early achalasia indicator) and dilation and thickening of the mucosa (advanced achalasia indicators). A mucosal entry site for peroral endoscopic myotomy was created using cap-fitted endoscopic mucosal resection to access the full-layer mucosa and the submucosa.

KEY RESULTS

Mucosal histology was compared between 32 patients with achalasia and 15 controls. Histological esophagitis with findings of inflammatory cell infiltration and dilated intercellular spaces was observed more in patients with achalasia than in controls (87.5% vs 13.3%, P<.001; 84.4% vs 46.7%, P=.049). Muscularis mucosae (MM) atrophy and epithelial wave were only observed in achalasia (40.6% vs 0%, P=.005; 28.1% vs 0%, P=.043). Fibrosis was more common in achalasia, but without statistical significance (31.3% vs 20.0%, P=.503). In achalasia with endoscopic dilation and thickening of the mucosa, MM atrophy was observed histologically, and in cases involving endoscopic PSP, the histological epithelial wave was observed.

CONCLUSIONS & INFERENCES

Histological findings of esophagitis were observed endoscopically even in early achalasia. Pinstripe pattern corresponds to the epithelial wave observed histologically in achalasia, whereas endoscopic findings in advanced achalasia correspond to MM atrophy. Appropriate management is necessary during early achalasia to prevent progression to advanced achalasia with more severe histological changes.

Changes in esophageal motility after endoscopic submucosal dissection for superficial esophageal cancer: a high-resolution manometry study

The effect of endoscopic submucosal dissection (ESD) on esophageal motility remains unknown. Therefore, the aim of this study is to elucidate changes in esophageal motility after ESD along with the cause of dysphagia using high-resolution manometry (HRM). This is a before-and-after trial of the effect of ESD on the esophageal motility. Twenty patients who underwent ESD for superficial esophageal carcinoma were enrolled in this study. Patients filled out a questionnaire about dysphagia and underwent HRM before and after ESD. Results before and after ESD were compared. Data were obtained from 19 patients. The number of patients who complained of dysphagia before and after ESD was 1/19 (5.3%) and 6/19 (31.6%), respectively (P = 0.131). Scores from the five-point Likert scale before and after ESD were 0.1 ± 0.5 and 1.0 ± 1.6, respectively (P = 0.043). The distal contractile integral (DCI) before and after ESD and the number of failed, weak, or fragmented contractions were not significantly different. However, in five patients with circumferential ESD, DCI was remarkably decreased and the frequency of fail, weak, or fragmented contractions increased. Univariate regression analysis showed a relatively strong inverse correlation of ΔDCI with the circumferential mucosal defect ratio {P < 0.01, standardized regression coefficient (r) = -0.65}, the number of stricture preventions (P < 0.01, r = -0.601), and the number of stricture resolutions (P < 0.01, r = -0.77). This HRM study showed that impairment of esophageal motility could be caused by ESD. The impairment of esophageal motility was conspicuous, especially in patients with circumferential ESD and subsequent procedures such as endoscopic triamcinolone injection and endoscopic balloon dilatation. Impaired esophageal motility after ESD might explain dysphagia.

Evaluating the effectiveness of RNA in-situ hybridization for detecting lung adenocarcinoma with anaplastic lymphoma kinase rearrangement

AIMS

An easy and rapid assay for detecting mRNA in formalin-fixed paraffin-embedded samples [RNA in-situ hybridization (ISH)] has been reported recently. The aim of this study was to investigate the diagnostic accuracy of RNA ISH in detecting lung adenocarcinoma (LA) with anaplastic lymphoma kinase (ALK) gene rearrangement.

METHODS AND RESULTS

We tested ALK RNA ISH on 11 resected LAs for which ALK fusion was confirmed by immunohistochemistry (IHC) and/or fluorescence in-situ hybridization (FISH). ALK mRNA expression was detected by RNA ISH in all 11 ALK-positive LAs, with a mean positive cell proportion of 68.4% (median, 75.3%; range, 3-98.8%), by counting 100 tumour cells at 10 different loci; RNA ISH did not detect ALK mRNA expression in the normal surrounding lung cells. Next, we explored the concordance between ALK RNA ISH and IHC/FISH tests by using tissue microarrays (TMAs) containing 294 LAs. In the TMA slides, we found five ALK-positive cases with IHC and/or FISH. The mean proportion of ALK RNA ISH-positive cells in these five cases was 75.6% (median, 82%; range, 40-94%), whereas the proportion of ALK RNA ISH-positive cells in the remaining 289 cases was 0.3% (median 0%; range, 0-15%). When the cutoff value was set at 15%, ALK RNA ISH-positive and ALK RNA ISH-negative cases were distinguishable with 100% sensitivity and specificity relative to the IHC/FISH tests.

CONCLUSIONS

Our findings show that RNA ISH is useful for detecting ALK rearrangement with high sensitivity and specificity relative to conventional IHC/FISH tests. Thus, RNA ISH, which is an easy and rapid assay, could be an alternative method to IHC and FISH.