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Schwannomas in and around the porta hepatis (porta hepatic schwannomas) are rare benign tumors easily misdiagnosed as other pathologies, including malignancies. We aimed to evaluate their imaging features on ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), andWe performed a multi-institutional retrospective study by reviewing the clinical and imaging findings of pathologically proven eight porta hepatic schwannomas (mean age, 55 years; range, 38-80 years; one male and seven females). Preoperative imaging included three ultrasonography, eight CT, eight MRI, and two FDG-PET/CT.All patients were asymptomatic. The mean tumor size was 61.9 mm (range, 30-180 mm), and all tumors demonstrated well-defined lesions on ultrasonography and their solid components showed soft tissue attenuation on non-contrast CT. MRI showed two distinct components in all cases: the component with T1-weighted hypointensities and T2-weighted hyperintensities with poor enhancement (suggestive of Antoni B histology); the component with T2-weighted hypointensities with gradually increasing enhancement (suggestive of Antoni A histology), resulting in a heterogeneous pattern on post-contrast CT or MRI (8/8, 100%). The separated deviation of surrounding bile ducts and vessels without obstruction allowed the recognition of extrahepatic localization and their benign nature. A ginger root-like morphology (2/8, 25%) seemed to be suggestive of extension along the Glisson's sheath, although this finding was not seen frequently.Recognizing imaging features such as extrahepatic location, benign nature with internal structures suggestive of Antoni A/B histology, and characteristic tumor extension may provide key diagnostic clues for porta hepatic schwannomas.

To assess the surgical outcomes of off-clamp open partial nephrectomy without renorrhaphy. In the era of robot-assisted surgeries, open partial nephrectomy remains a surgical option for ≥ T1b renal tumours. Although the necessity of renal pedicle clamping and renorrhaphy in open partial nephrectomy for larger tumours remains to be discussed, reports on this issue are rare. Twenty-seven open partial nephrectomies for ≥ T1b renal tumours were performed without renal pedicle clamping or renorrhaphy. A soft coagulation system was used to control bleeding from the resection bed. Surgical results, complications, and predictors of perioperative estimated glomerular filtration rate (eGFR) preservation at 1 month and 3 months after surgery were analysed. The median estimated volume of blood loss was 420 mL. The rates of perioperative eGFR preservation were 88.9 and 87.3% at 1 and 3 months after surgery, respectively. Tumour size was an independent predictor of perioperative eGFR preservation at 1 month after surgery, whereas age and exophytic/endophytic properties of the tumour were independent predictors of perioperative eGFR preservation at 3 months after surgery. Open partial nephrectomy without renal pedicle clamping or renorrhaphy could be safely performed for ≥ T1b renal tumours, even when tumours were entirely endophytic and located close to the renal pedicle. Mild perioperative eGFR reduction was observed. Although surgical indications should be carefully considered in these cases, off-clamp open partial nephrectomy without renorrhaphy is a feasible procedure for patients with ≥ T1b renal tumours.

Abstarct Purpose The purpose of this study is to describe the characteristic MRI, CT, and 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) findings of Wolffian tumor. Methods We reviewed preoperative images in four surgical cases of Wolffian tumor. MRI was available for review in all cases with additional diffusion-weighted images (DWI) in three, and contrast-enhanced images in two. CT was available in three. FDG-PET/CT was obtained in two. Results Two patients were asymptomatic, while the other two presented with acute abdomen. On MRI, all tumors were well-defined masses of increased signals on T2WI. Three tumors were solid, whereas the other was solid and cystic. The normal ipsilateral ovary was identified in two patients of reproductive ages, but not in two postmenopausal patients. Tumors in two patients presented with acute abdomen were complicated by hemorrhage. All three tumors evaluated on DWI showed high intensities. Contrast-enhanced images of MRI and CT showed homogeneous enhancement as the same degree as the myometrium. On CT, one tumor contained punctate calcifications. FDG-PET/CT showed moderate FDG accumulation. Conclusion Wolffian tumors may be typically solid extraovarian tumors occasionally associated with cysts and calcifications. Although they are benign, they mimic malignancy due to high intensities on DWI and increased FDG accumulation.

We measured the concentrations of cesium isotopes (

Introduction Granulomatous prostatitis is a benign inflammatory condition of the prostate that may mimic prostatic adenocarcinoma on magnetic resonance imaging findings. Even in the era of multiparametric magnetic resonance imaging, the differential diagnosis of granulomatous prostatitis from malignancy remains difficult. Case presentation A 69‐year‐old man with abnormal magnetic resonance imaging and positron emission tomography/magnetic resonance imaging findings, and a prostate‐specific antigen value of 2.48 ng/mL underwent prostate needle biopsy. He had a history of urinary tract infection 3 months prior to presentation. Multiparametric magnetic resonance imaging showed low‐intensity signals on T2‐weighted images, slightly high‐intensity signals on diffusion‐weighted images, and low values on apparent diffusion coefficients. The prostate imaging‐reporting and data system version 2 score was 3. Histological examination revealed granulomatous prostatitis. Conclusion For patients with preceding urinary tract infections, granulomatous prostatitis should be considered as a differential diagnosis, even when magnetic resonance imaging and positron emission tomography suggest prostatic adenocarcinoma.

Solitary pulmonary capillary hemangiomas (SPCHs) are recently recognized, rare benign lesions that form solitary nodules owing to capillary proliferation. These lesions are usually detected incidentally as small ground-glass nodules (GGNs) on computed tomography (CT), and progressively enlarge over time. The radiological distinction from peripheral lung cancers is particularly challenging. However, to date, there have been no reports on progressive changes in the central density of SPCH on CT. An asymptomatic 49-year-old man was referred to our hospital for an abnormal shadow that was detected on chest CT during medical check-up. He was subsequently followed-up with chest CT. The nodule increased in size, and the central area became progressively denser. He underwent surgery 5 years and 10 months after the first visit owing to suspicion of lung cancer. Despite the collapse of the surgical specimen by artifacts, histopathological examination revealed a diagnosis of SPCH; collagenous fibers were found in the walls of the intralesional capillaries. The patient is presently alive without any recurrence, 6 months after the operation. In this case, the SPCH demonstrated a GGN with progressively increasing density of the central solid area on the CT. This remarkable feature made the preoperative distinction from lung cancer particularly difficult.

An international review of radioecological data derived after the accident at the Fukushima Daiichi nuclear power plant was an important component of activities in working group 4 of the IAEA Models and data for radiological impact assessment, phase II (MODARIA II) programme. Japanese and international scientists reviewed radioecological data in the terrestrial and aquatic environments in Japan reported both before and after the accident. The environmental transfer processes considered included: (a) interception and retention radionuclides by plants, (b) loss of radionuclides from plant and systemic transport of radionuclides in plants (translocation), (c) behaviour of radiocaesium in soil, (d) uptake of radionuclides from soil by agricultural crops and wild plants, (e) transfer of radionuclides from feedstuffs to domestic and wild animals, (f) behaviour of radiocaesium in forest trees and forest systems, (g) behaviour of radiocaesium in freshwater systems, coastal areas and in the ocean, (h) transport of radiocaesium from catchments through rivers, streams and lakes to the ocean, (i) uptake of radiocaesium by aquatic organisms, and (j) modification of radionuclide concentrations in food products during food processing and culinary preparation. These data were compared with relevant global data within IAEA TECDOC-1927 ‘Environmental transfer of radionuclides in Japan following the accident at the Fukushima Daiichi Nuclear Power Plant’. This paper summarises the outcomes of the data collation and analysis within MODARIA II work group 4 and compares the Japan-specific data with existing radioecological knowledge acquired from past and contemporary radioecological studies. The key radioecological lessons learned are outlined and discussed.

Pulmonary thromboembolism (PTE) is one of the leading causes of death among cancer outpatients. The aim of the present study was to investigate the reliability and validity of D-dimer monitoring for PTE in patients with unresectable, advanced or recurrent colorectal cancer treated with bevacizumab. A total of 25 patients with advanced colorectal cancer who received bevacizumab combination chemotherapy as primary treatment were retrospectively reviewed. The selection criteria included that D-dimer tests were performed repetitively, and that chest and abdominal contrast-enhanced CT scans were completed. The D-dimer levels and the presence or absence of PTE on CT images were retrospectively examined. Four cases (16%) were detected as having asymptomatic PTE. The D-dimer values at the onset of PTE were 14.2, 4.6, 1.1 and 0.9 µg/ml. The negative predictive value was 90.5% when 3.0 µg/ml was set as the D-dimer level cutoff value. The incidence of PTE, including asymptomatic PTE, in the present study was higher compared with that reported in previous studies on various types of cancer, of various stages and treated with different chemotherapy regimens. In patients with bevacizumab-treated unresectable, advanced or recurrent colorectal cancer, the D-dimer test was found to be less useful for exclusion diagnosis; however, along with chest CT, it may be useful in the detection and diagnosis of PTE. However, the determination of the optimal reference values and appropriate measurement timing of D-dimer testing requires further study.

Radioactivity concentrations of 137Cs in seawaters and bottom sediments have been measured in the coastal waters off all nuclear power plant sites in Japan. Sediment distribution coefficient (Kd) values obtained before the Fukushima Daiichi Nuclear Power Plant accident were variable and related to the specific surface area of the bottom sediment. A mathematical model suggested that before the accident the Kd values were in the transient state approaching a dynamic equilibrium with a converged Kd value of 1000–1600. Based on a post-accident mathematical model, the apparent Kd reached the maximum of about 104 and then decreased until now, converging to 6 × 103 on average.

Complex aortic atheroma is a high-risk factor for recurrent embolic stroke. An accurate identification of stroke etiology is clinically important; however, it can be challenging. A 91-year-old man with atrial fibrillation was diagnosed with cardioembolic stroke and treated with mechanical thrombectomy. The removed thrombus microscopically contained foamy cells, suggesting an atheroembolism. An autopsy revealed an atherosclerotic lesion with ulceration, located in the aortic arch. At the lesion, the plaque had microscopically ruptured into the lumen. We therefore concluded that the aortic atherosclerotic lesion was the embolic source. Removed thrombi should be pathologically examined even if a cardioembolic stroke is clinically suspected.

Cerebral embolism after left upper lobectomy caused by a thrombus in the pulmonary vein stump (PVS) is a serious complication. However, it is unclear if cerebral embolism can develop after other types of lobectomy. We present a case of a 68-year-old man with cerebral embolism after left lower lobectomy with a longer PVS than normal. There were no clinically suspected sources for the thrombus except for the PVS. This thrombus seemed to have formed in the PVS. The endovascularly removed thrombus contained scattered nuclear debris around neutrophils, suggesting a physiological response caused by tissue injury.

Metastatic diseases rarely develop in the colorectum, and diagnosing colorectal metastasis by biopsy without history of a malignant tumor or clinical information of a primary tumor is challenging. A 65-year-old woman with a 6-month history of constipation and diarrhea was admitted to our hospital and diagnosed with rectosigmoid colonic micropapillary carcinoma. Low anterior resection was performed after neoadjuvant chemotherapy. Because the lipoleiomyoma in the uterus obstructed the operator’s vision, total hysterectomy and bilateral salpingo-oophorectomy were performed. Examination of the colon and adnexa, together with immunohistochemical studies, revealed that the colonic tumor was actually serous carcinoma that had metastasized from the left fimbria of the fallopian tube. Retrospective immunohistochemical examination of the colon biopsy specimen suggested carcinoma with a Müllerian immunophenotype. When a colon biopsy reveals carcinoma with an invasive micropapillary pattern without a component of conventional tubular adenocarcinoma, immunohistochemical examination should be performed to rule out the possibility of metastasis.

The

Monitoring of 137Cs in seawater in coastal areas around Japan between 1983 and 2016 yielded new insights into the sources and transport of Fukushima Daiichi Nuclear Power Plant (FDNPP)-derived 137Cs, particularly along the west coast of Japan. Before the FDNPP accident (1983–2010), the activity concentrations of 137Cs, mainly from fallout, were decreasing exponentially. Effective 137Cs half-lives in surface seawater ranged from 15.6 to 18.4 yr. After the FDNPP accident (March 2011) 137Cs activity concentrations in seawater off Fukushima and neighboring prefectures immediately increased. Since May/June 2011, 137Cs activity concentrations there have been declining, and they are now approaching preaccident levels. Along the west coast of Japan remote from FDNPP (i.e., the Japan Sea), however, radiocesium activity concentrations started increasing by 2013, with earlier (May/June 2011) increases at some sites due to airborne transport and fallout. The inventory of 137Cs in the Japan Sea (in the main body of th...

Since 1991 radioactivity concentration of tritium (3H) in seawater has been monitored in the coastal waters off Rokkasho, Aomori Prefecture, where a commercial nuclear fuel reprocessing plant was in intermittent test operation beginning from 2006 and ending in 2008. Average 3H radioactivity concentrations, mainly derived from global fallout of atmospheric nuclear weapons tests in the 1950′s and early 1960′s, decreased from 0.28 Bq/L in 1991 to 0.13 Bq/L in 2006 due to water mixing and radioactive decay. The concentrations in the southern part of the monitoring area increased to the maximum value of 1.3 Bq/L during the active test period, 2007 to 2008. Since 2009, the concentrations have been in the same declining trend as before the active test period; hence, 3H inventory in the monitoring area has been decreasing with minor impact from the active test for a brief period (

Radioactivity has been monitored in seafloor sediments off Fukushima and nearby prefectures regularly. During the initial monitoring period (May–September 2011), 137Cs concentrations in the surface sediments (0–3 cm) generally increased to 8–580 Bq/kg. Subsequently, concentrations decreased at variable rates. In the latest data, from February 2016, concentrations were still higher at 0.8–141 Bq/kg than the pre-accident level. The geometric mean concentration declined steadily from 47 Bq/kg in September 2011 to 13 Bq/kg in February 2016. The 137Cs abundance (Bq/m2) in the surface sediment at each station decreased similarly. The rate of decrease of surface abundance varied spatially by almost one order of magnitude, ranging from 1.1 × 10−4 to 1.7 × 10−3/day, equivalent to halving times of 16–1.1 years, respectively. The rate of decrease was related to the median sediment grain size at each station. In addition, bottom-water dynamics, through the redistribution of bottom sediments, may have caused spatial variability in the rate of decrease, whereas vertical profiles of 137Cs concentrations in the sediment suggest that vertical migration of 137Cs was not a major mechanism reducing the surface 137Cs concentration. From September 2011 to February 2016, the overall halving time of 137Cs in the surface sediment in the monitoring area, excluding the area inside a 30-km radius from the Fukushima Dai-ichi Nuclear Power Plant, was 2.3 years. Thus, 76% of the originally deposited 137Cs (46 × 1012 Bq) in the surface sediment was transported out of the area during that period.

This study aimed to investigate the frequency of fat retention in the bladder using postoperative computed tomography (CT) and the associated imaging or clinical findings in patients who underwent renal tumor surgery. We retrospectively reviewed postoperative CT images from 123 patients who underwent surgery for renal tumors (92 patients after partial nephrectomy and 31 after total nephrectomy). Furthermore, we evaluated preoperative tumor characteristics per an established standardized nephrometry scoring system (the R.E.N.A.L Nephrometry Score) for patients with partial nephrectomy. We also investigated whether collecting system repair occurred during surgery. Fat retention in the bladder was found in 5 patients (5.4%) after partial nephrectomy, but was not observed in any patients after total nephrectomy. No fat retention was seen immediately after partial nephrectomy (4–8 days), but occurred 2–15 months after the surgery. Subsequently, intravesical fat retention disappeared in 3 patients (8, 24, and 16 months later), and it persisted from 19–22 months after surgery in the remaining 2 patients. Collecting system repair occurred in 25 patients (27%) with partial nephrectomy. There was no statistically significant association between fat retention in the bladder and intraoperative collecting system repair (p = 0.12). The association with intravesical fat retention was not significant for either tumor size, distance to the collecting system, or the R.E.N.A.L. Nephrometry Score. Fat retention in the bladder after partial nephrectomy can be observed using CT, although it is relatively rare. It is clinically asymptomatic and disappears spontaneously in most cases.

Cerebral embolism is a very serious complication after lung cancer surgery. In such cases, cerebral embolism is caused by a thrombus formed in the pulmonary vein stump. Most such cases have been reported to occur within 10 days after left upper lobectomy. The patients were treated with anticoagulation therapy to prevent the recurrence of cerebral embolism, and recurrence or thrombus reformation has not been reported to the best of our knowledge. We present a 68-year-old man with a cerebral embolism detected on the day after left upper pulmonary lobectomy for lung cancer. The patient was treated with unfractionated heparin and his neurological symptoms improved. Heparin treatment was subsequently changed to aspirin for the prevention of recurrence; however, thrombus formation in the vein stump was asymptomatically confirmed 16 months after the surgery by contrast-enhanced computed tomography. This is the first case to our knowledge of thrombus reformation in the pulmonary vein stump after a cerebral embolism associated with lung cancer surgery. In our case, anticoagulation therapy was not continued to prevent recurrence, and antiplatelet therapy was performed instead, which might be associated with the thrombus reformation.

In intralobar pulmonary sequestrations, vascular changes similar to those in pulmonary hypertension (PH) are generally observed, such as intimal proliferation and plexiform lesions. However, to our knowledge, a sequestrated lung manifesting vascular changes with both arteritis and a plexiform lesion has never been reported. A 25-year-old man was diagnosed with intralobar pulmonary sequestration. Pathologically, both arteritis and a plexiform lesion were observed in the sequestrated lung. Systemic vasculitis syndrome was clinically excluded, and the pathological findings appeared to be associated with local PH. Arteritis is an extremely rare finding; only one case of arteritis associated with local PH has been reported in intralobar sequestration. In this case, the artery near the plexiform lesion had milder inflammation and fibrosis, suggesting that the arteritis formed prior to the plexiform lesion. This is the first case of arteritis and a plexiform lesion co-occurring in intralobar pulmonary sequestration associated with local PH. This case may shed light on the formation of plexiform lesions and their association with arteritis.

Carcinosarcomas with elements of cholangiocarcinoma and sarcoma are rare and have a poor prognosis. The spreading pattern and radiological findings of these lesions remain unclear. A 74-year-old man presented with a high γ-glutamyl transferase level. Magnetic resonance imaging revealed dilation of the right intrahepatic and common bile ducts, consistent with an intraductal papillary neoplasm of the bile duct (IPNB), and diffusion-weighted imaging (DWI) indicated an area of high signal intensity in the intrahepatic bile duct. Bile duct biopsy yielded a small amount of atypical spindle cells, and the patient underwent a right hepatectomy. Microscopically, the tumor contained cholangiocarcinoma and sarcomatous components, including osteosarcoma and leiomyosarcoma, leading to a diagnosis of intrahepatic carcinosarcoma. The tumor spread primarily through the intrahepatic bile duct. An accurate radiological diagnosis of carcinosarcoma was challenging, given the apparent similarities with IPNB. The findings from DWI and pathology of a bile duct biopsy may assist with preoperative diagnosis.

Concentration ratios (CRs), expressed by dividing

We reviewed six cases suspected of having fish bones in the bile ducts on follow-up CT following pancreaticoduodenectomy. The period from surgery to CT examination in which fishbone migration was first suspected ranged from 282 to 1157 days with a median of 517 days. The fish bone in the bile duct disappeared in five out of six cases on subsequent CT. One case was complicated by hepatolithiasis, and the other five cases showed no biliary complications. In two cases, wandering of fish bones in the jejunal limb was observed on CT images before their migration into the bile ducts. Asymptomatic migration of fish bones to the bile ducts following pancreaticoduodenectomy is not rare, but serious complications can occasionally occur. Indications of intervention may be controversial in asymptomatic cases, but once fish bones are observed in the biliary tree or the jejunal limb, dietary instructions advising not to swallow fish bones may be a good option to prevent complications.

Enterocolic lymphocytic phlebitis (ELP) is a rare enteropathy characterized by lymphocytic phlebitis of the mesenteric veins without arteritis. Idiopathic myointimal hyperplasia of mesenteric veins (IMHMV) is a rare disease similar to ELP, characterized by myointimal hyperplasia that constricts the lumen of veins, causing mucosal injury. A 62-year-old man with chief complaint of abdominal pain was treated by partial resection of the ileum after 3 months of conservative therapy. The pathologic diagnosis was ELP with prominent myointimal hyperplasia. Histologically, the lesion consisted of lymphocytic infiltration into the vein accompanied by prominent myointimal hyperplasia and perivenous concentric fibrosis, which are characteristics shared by ELP and IMHMV. The observations in this case suggest that some of ELP and IMHMV may belong to the same disease spectrum. Furthermore, perivascular concentric fibrosis was a remarkable observation that may contribute to differential diagnosis between ELP and “true” IMHMV.

The 238Pu, 239+240Pu, 241Am, 242Cm, 243+244Cm and 90Sr concentrations in seafloor surface sediments collected at three sampling stations off the Fukushima Daiichi Nuclear Power Plant (FDNPP) site during the period from 2012 to 2019 were determined to elucidate the impacts of the FDNPP accident onto their concentrations in coastal sediments and to discuss the sources of the measured radionuclides. The 239+240Pu, 241Pu and 241Am concentrations and 240Pu/239Pu atom ratios in a sediment core were also determined to allow comparison of their inventories between this study and previously reported values and to identify the Pu sources. The 238Pu, 239+240Pu, 241Am and 90Sr concentrations showed no remarkable temporal variations; no significant increases in concentrations after the FDNPP accident were observed; these concentrations were comfortably within the previously reported concentration range; and no detectable 242Cm and 243+244Cm amounts were observed in surface sediments. The observed 238Pu/239+240Pu activity ratios were approximately two orders of magnitudes lower than those for the damaged FDNPP reactor core inventories and the observed values in terrestrial samples after the accident. The 239+240Pu, 241Pu and 241Am inventories in the sediment core were 389 ± 5, 503 ± 33 and 214 ± 3 Bq m−2, respectively. The 239+240Pu inventory was about an order of magnitude greater than the expected cumulative deposition density of global fallout from atmospheric nuclear weapons testing due to an enhanced scavenging effect. The 240Pu/239Pu atom ratios in the sediment core ranged from 0.239 to 0.246 with a mean value of 0.242 ± 0.002; these ratios were clearly greater than the mean global fallout ratio of 0.18. The results for 238Pu/239+240Pu activity ratios and 240Pu/239Pu atom ratios reflected a mixture of global fallout and Pacific Proving Grounds (PPG) close-in fallout Pu rather than Fukushima accident-derived Pu. The sediment column inventory for 239+240Pu originating from the PPG close-in fallout was calculated as 166 Bq m−2, which corresponded to 43% of the total inventory. A significant amount of the PPG-derived Pu has been transported by ocean currents and then preferentially scavenged in the coastal waters of Japan.

Concentrations of 129I and 127I in kelps (Saccharina) collected from coastal waters off northern Japan were monitored from 2007 to 2019. During the 2007–2008 test operation of the Rokkasho nuclear fuel reprocessing plant, 129I discharge from the plant increased, and the 129I concentration and 129I/127I atom ratio in the kelps reached maxima of 42 μBq/g-dry and 264 × 10−11, respectively. By 2009, both had decreased by one order of magnitude. After the Fukushima Dai-ichi Nuclear Power Plant accident in 2011, the 129I concentration and 129I/127I atom ratio in the kelps increased to 2.24 μBq/g-dry and 11.6 × 10−11, respectively. After 2012, the ratio in kelps decreased to (2.1–8.9) × 10−11, which is almost the same as the seawater value off Aomori Prefecture before the test operation. The 129I/127I atom ratio in kelps thus represents the ambient seawater ratio during the growth period of the kelps.

Solitary pulmonary capillary hemangioma (SPCH) is a rare disease, first described about autopsy cases in 2000 and about surgically resected cases in 2006. To date, only 9 surgically resected cases have been published in English. Here, we report 7 original cases with surgery (median age, 54 y; 4 females, 2 never-smokers). All patients were asymptomatic, and all nodules were detected by computed tomography (CT). The median (range) size of nodule was 11 (8 to 16) mm. Six of 7 cases showed the part-solid nodule appearance and 1 showed pure ground-glass nodule appearance in CT findings. The growth speed was very slow. No abnormal uptake of fluorine-18 fluorodeoxyglucose was observed in systemic positron-emission CT in all 3 cases we examined. No patients died from SPCH. Histologically, SPCH manifested as a solitary lesion composed of densely proliferating and dilated capillaries without cytologic atypia within the alveolar septa. In addition, capillaries of SPCH spread into the vascular lumen and involved the walls of bronchioles with protrusion into the lumen. Immunohistochemically, capillaries of SPCH uniformly expressed endothelial markers, such as CD31, CD34, and Factor VIII; and α-smooth muscle actin positive cells were also observed. To be accurately diagnosed, especially in intraoperative frozen sections, SPCH should be conceived as an entity that presents as a solitary nodule in CT. We propose that SPCH is an unrecognized benign capillary proliferative disease.

We have evaluated the contribution of sources of (137)Cs to the inventory of radiocesium in waters (surface area: 6160 km(2), water volume: 753 km(3)) off Fukushima Prefecture and neighboring prefectures from May 2011 to February 2015. A time-series of the inventory of (137)Cs in the offshore waters revealed a clearly decreasing trend from May 2011 (283.4 TBq) to February 2015 (1.89 TBq). The (137)Cs inventory about four years after the accident was approximately twice the background inventory of 1.1 TBq. The magnitudes of the (137)Cs influxes from sources into offshore waters for periods of 182-183 days were estimated from the first period (1 October 2011 to 31 March 2012: 15.3 TBq) to the last period (1 October 2014 to 31 March 2015: 0.41 TBq). We assumed that three sources contributed (137)Cs: continuous direct discharge from the Fukushima Dai-ichi Nuclear Power Station (FNPS) even after the massive discharge in late March 2011, desorption/dissolution from sediments, and fluvial input. Quantification of these sources indicated that the direct discharge from the FNPS is the principal source of (137)Cs to maintain the relatively high inventory in the offshore area.

Autoradiography was used to detect 137Cs-enriched particles in sediment samples. The contributions of 137Cs-enriched particles to 137Cs concentrations in sediment samples ranged from 9% to 64%. These experiments revealed that the variability of 137Cs concentrations was due mainly to the heterogeneous distribution of 137Cs-enriched particles in the samples. Therefore, the heterogeneous distribution of 137Cs-enriched particles is probably one of the main factors responsible for the temporal and spatial variations of 137Cs concentrations in sediment samples.

Monitoring of

We evaluated the influence of radiocesium (137Cs) desorbed from riverine particles on the export flux of dissolved 137Cs from rivers to the marine environment, where it may accumulate and become concentrated in marine biota. The samples were collected from stations along the Abukuma (December 2013), Kuji (November 2013), Naka (November 2013), and Tone (October 2013) rivers, in the catchments of which large quantities of radionuclides from the Fukushima Dai-ichi Nuclear Power Plant (FNPP) accident were deposited. We estimated the extent of the desorbed fraction from riverine particles by conducting a particle–seawater partitioning and desorption experiment in which sieved particles ( 1000 Bq/kg-dry) to the marine environment, thereby increasing the contribution of desorption to the export flux of dissolved 137Cs. These results show that reactive particulate Cs (i.e., the desorbable fraction) must be taken into account when estimating the radiocesium fluxes from rivers to coastal regions near the FNPP.

Necrotizing arteritis is a complex lesion of pulmonary hypertension, as are plexiform lesions, and is classically recognized as grade 6 in the Heath and Edwards grading scheme for hypertensive pulmonary vascular disease. The vascular changes observed in intralobar pulmonary sequestration have been reported to be similar to those observed in pulmonary hypertension, such as plexiform lesions. However, necrotizing arteritis occurring in an intralobar sequestration of a patient without systemic vasculitis syndrome has never been reported to our knowledge. Here, we report a case of a 38-year-old woman with pulmonary sequestration detected on a medical checkup. She was treated with surgery, and subsequent pathological analyses revealed necrotizing vasculitis in her sequestrated lung. We suspected systemic vasculitis syndromes, such as Takayasu arteritis, polyarteritis nodosa, and antineutrophil cytoplasmic antibody-associated vasculitis. However, physical and blood examination did not show any other abnormalities, and hence, she did not have systemic vasculitis syndrome. Immunohistochemical analyses of the resected specimen showed that inflammatory cells of the arteries were mainly composed of T lymphocytes. T-lymphocytic inflammation with little neutrophil and histiocyte infiltration may be a pathological feature of necrotizing arteritis observed in pulmonary sequestration. This is the first case to our knowledge of necrotizing arteritis in an intralobar pulmonary sequestration of a patient without systemic vasculitis syndrome.

After the Fukushima Daiichi Nuclear Power Plant accident in March 2011, concentrations of cesium isotopes (133Cs, 134Cs, and 137Cs) were measured in zooplankton collected in the Pacific off the east coast of Japan from May 2012 to February 2015. The time series of the data exhibited sporadic 137Cs concentration peaks in zooplankton. In addition, the atom ratio of 137Cs/133Cs in zooplankton was consistently high compared to that in ambient seawater throughout the sampling period. These phenomena cannot be explained fully by the bioaccumulation of 137Cs in zooplankton via ambient seawater intake, the inclusion of resuspended sediment in the plankton sample, or the taxonomic composition of the plankton. Autoradiography revealed highly radioactive particles within zooplankton samples, which could be the main factor underlying the sporadic appearance of high 137Cs concentrations in zooplankton as well as the higher ratio of 137Cs/133Cs in zooplankton than in seawater.

The concentrations of 239+240Pu, 241Pu and 241Am in the sediments at the coast of Japanese islands from 2008 to 2011 varied widely from one sampling site to another and were generally lower in sandy sediments at shallower sites, and higher in clayey sediments at deeper sites. In contrast, there seemed to be no temporal variation in the concentrations during the survey period. The 241Am/239+240Pu activity ratio was relatively higher than the global fallout presumably owing to the ingrowth of 241Am from the ancestor, 241Pu originating mainly from the hydrogen bomb explosion tests in the Marshall Islands in the 1950s.

Concentrations of radiocesium (134Cs and 137Cs) were measured in zooplankton in the waters of Miyagi, Fukushima, and Ibaraki Prefectures from May 2012 to January 2013. They varied from 0.1 to 9.1 Bq/kg-wet, and from 0.1 to 12.8 Bq/kg-wet for 134Cs and 137Cs, respectively. The zooplankton-to-water concentration ratio (CR) of 137Cs was calculated to be 20–1410 L/kg. Export fluxes of 137Cs by zooplankton were estimated to be 13–165 mBq/m2/y. The contribution of zooplankton for the downward transport of 137Cs was at most 18 % of the previously reported export fluxes of 137Cs by sinking particles as obtained from sediment trap observations.

The activities of artificial radionuclides in seawater samples collected off the coast of Miyagi, Fukushima, and Ibaraki Prefectures were measured as part of a monitoring program initiated by the Japanese Ministry of Education, Sports, Science and Technology immediately after the Fukushima Dai-ichi Nuclear Power Plant accident. The spatial and temporal distributions of those activities are summarized herein. The activities of strontium-90, iodine-131, cesium-134 and -137 (i.e. 90Sr, 131I, 134Cs, and 137Cs) derived from the accident were detected in seawater samples taken from areas of the coastal ocean adjacent to the power plant. No 131I was detected in surface waters (≤ 5 m depth) or in intermediate and bottom waters after 30 April 2011. Strontium-90 was found in surface waters collected from a few sampling stations in mid-August 2011 to mid-December 2011. Temporal changes of 90Sr activity in surface waters were evident, although the 90Sr activity at a given time varied widely between sampling stations. The activity of 90Sr in surface waters decreased slowly over time, and by the end of December 2011 had reached background levels recorded before the accident. Radiocesium, 134Cs and 137Cs, was found in seawater samples immediately after the accident. There was a remarkable change in radiocesium activities in surface waters during the first 7 months (March through September 2011) after the accident; the activity reached a maximum in the middle of April and thereafter decreased exponentially with time. Qualitatively, the distribution patterns in surface waters suggested that in early May radiocesium-polluted water was advected northward; some of the water then detached and was transported to the south. Two water cores with high 137Cs activity persisted at least until July 2011. In subsurface waters radiocesium activity was first detected in the beginning of April 2011, and the water masses were characterized by σt (an indicator of density) values of 25.5–26.5. From 9–14 May to 5–16 December 2011, the depths of the water masses increased with time, an indication that deepening of the isopycnal surfaces with time can be an important mechanism for the transport of radiocesium downward in coastal waters. During 4–21 February 2012, the water column became vertically homogeneous, probably because of convective mixing during the winter; the result was nearly constant values of radiocesium activity throughout the water column from the surface to the bottom (~200 m depth) at each station.

Spatiotemporal distributions of anthropogenic radionuclides in marine surface sediments off Miyagi, Fukushima, and Ibaraki Prefectures were analyzed on the basis of data collected during the monitoring program launched by the Japanese Ministry of Education, Sports, Science and Technology in 2011 right after the Fukushima Dai-ichi Nuclear Power Plant accident began. Concentrations of 137Cs in the surface sediments varied spatially by two orders of magnitude, from 1.7 to 580 Bq kg-dry−1, and there was no obvious correlation between 137Cs concentration and the proximity of the sampling location to the accident site. The total inventory of 137Cs accumulated in the upper 3 cm of surface sediments in the monitoring area was estimated to be 3.78 × 1013 Bq, that is, 0.1–2% of the total 137Cs flux from the plant to the ocean as a result of the accident (the percentage depends on the model used to estimate the total flux). The spatial variations of 137Cs concentration and inventory depended on two main factors: the 137Cs concentration in the overlying water during the first several months after the accident and the physical characteristics of the sediments (water content and bulk density). The temporal variations of the concentrations of other anthropogenic radionuclides (90Sr, 95Nb, 110 mAg, 125Sb, 129Te, and 129 mTe) in the sediments were also investigated. Activity ratios of these nuclides to 137Cs suggest that the nuclides themselves were not homogenized before they were removed from seawater to the sediments.

Vascular changes observed in intralobar pulmonary sequestration (PS) have been reported to be similar to those observed in pulmonary hypertension (PH). However, atherosclerosis in the pulmonary artery, which is one of the characteristic arterial changes of PH, has scarcely been reported in PS. Here, we report this unique manifestation in a 66-year-old man, in whom an intralobar PS fed by an aberrant artery branching from the left gastric artery had been identified 10 years earlier, and who was diagnosed with pneumonia after having symptoms of fever and cough. He was treated by lobectomy of the lower lobe of his right lung. Subsequently, a culture test of the fluid from the sequestrated lung was performed, which identified Mycobacterium avium. Subsequent pathological examination of the sequestrated lung demonstrated multiple epithelioid cell granulomas. Furthermore, atherosclerosis of the aberrant artery was also found, which may be associated with his advanced age. This is an extremely rare case of right intralobar PS supplied by aberrant artery with atherosclerosis originating from left gastric artery passing over the diaphragm.