Cutaneous syncytial myoepithelioma with folliculocentric growth and EWSR1 gene rearrangement: A case report.

Cutaneous syncytial myoepithelioma is a tumor type that was initially reported in 2013 as a syncytial variant of cutaneous myoepithelioma characterized by intradermal nodular proliferation of oval to spindle-shaped tumor cells in solid and syncytial patterns. Fusion of genes Ewing sarcoma breakpoint region 1 / EWS RNA binding protein 1 (EWSR1) and pre-B cell leukemia homeobox 3 (PBX3) is found in approximately 90% of the cases. We report a case of cutaneous syncytial myoepithelioma with diagnostic difficulty due to folliculocentric morphology and atypical immunohistochemical results, including diffuse positivity of α-smooth muscle actin and claudin 4 and negative immunoreactions for epithelial membrane antigen and S100 protein. In the present case, fluorescence in situ hybridization study demonstrated EWSR1 rearrangement. We further provide a discussion of differential diagnoses with a review of relevant literature.

Clinically relevant model of oxaliplatin-induced sinusoidal obstruction syndrome.

AIM: Sinusoidal obstruction syndrome (SOS) induced by oxaliplatin-including chemotherapies (OXCx) is associated with impaired hepatic reserve and higher morbidity after hepatic resection. However, in the absence of an appropriate animal experimental model, little is known about its pathophysiology. This study aimed to establish a clinically relevant reproducible model of FOLFOX-induced SOS and to compare the clinical/histopathological features between the clinical and animal SOS settings. METHODS: We performed clinical/pathological analyses of colorectal liver metastasis (CRLM) patients who underwent hepatectomy with/without preoperative treatment of FOLFOX (n = 22/18). Male micro-minipigs were treated with 50% of the standard human dosage of the FOLFOX regimen. RESULTS: In contrast to the monocrotaline-induced SOS model in rats, hepatomegaly, ascites, congestion, and coagulative necrosis of hepatocytes were absent in patients with CRLM with OXCx pretreatment and OXCx-treated micro-minipigs. In parallel to CRLM cases with OXCx pretreatment, OXCx-challenged micro-minipigs exhibited deteriorated indocyanine green clearance, morphological alteration of liver sinusoidal endothelial cells, and upregulated matrix metalloproteinase-9. Using our novel porcine SOS model, we identified the hepatoprotective influence of recombinant human soluble thrombomodulin in OXCx-SOS. CONCLUSIONS: With distinct differences between monocrotaline-induced rat SOS and human/pig OXCx-SOS, our pig OXCx-SOS model serves as a preclinical platform for future investigations to dissect the pathophysiology of OXCx-SOS and seek preventive strategies.

Eosinophilic pustular folliculitis developing at the site of COVID-19 vaccination.

We present a rare case of eosinophilic pustular folliculitis due to mRNA-based vaccines for COVID-19. Histology of the biopsy specimen was very interesting.

[A Case of Primary Testicular Mucinous Carcinoma].

A 68-year-old man presented withleft testicular painless swelling. His carbohydrate antigen 19-9 and carcinoembryonic antigen levels were elevated but his germ cell tumor markers were not high. Magnetic resonance imaging showed multiloculated cystic lesions with solid components in his left testis. Abdominal and chest computed tomography revealed multiple lung metastases, peritoneal dissemination and multiple lymph node metastases. Left high orchiectomy was performed. Histopathological examination demonstrated testicular mucinous carcinoma withsimilarity to gastric cancer. Since no tumor was found by the endoscopy of the upper gastrointestinal and the lower digestive tract, we diagnosed the patient with primary testicular mucinous carcinoma. Standard chemotherapy for gastric cancer, which consisted of tegafur, gimeracil and oteracil (TS-1) and cisplatin was administered for 16 months, and there was no progression of the disease. He died from testicular mucinous cancer 30 months after the diagnosis. In the literature, only 4 cases of testicular mucinous carcinoma have been reported. TS-1 and cisplatin are useful chemotherapeutic options for testicular mucinous carcinoma withmetastasis.

Proliferating EpCAM-Positive Ductal Cells in the Inflamed Liver Give Rise to Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) originates from regenerating liver cells with genetic alterations in chronically inflamed liver. Ductal cells and hepatocytes proliferate for liver regeneration, and proliferating ductal cells (PDC) derived from bile ductules have long been considered putative liver stem/progenitor cells and candidate cellular origins of HCC. The potential of PDC as tumor-originating cells, however, remains controversial in contrast to accumulating evidence that HCC originates from hepatocytes. Here, we demonstrate that PDCs expressing the established surface and cancer stem cell marker EpCAM give rise to HCC in inflamed liver. EpCAM-expressing PDCs were specifically labeled in newly developed EpcamCreERT2 mice and traced in a chemically induced liver injury model. Stepwise accumulation of genetic alterations in EpCAM-positive cells was induced by the mutagenesis activity of activation-induced cytidine deaminase using conditional transgenic mice. Lineage-tracing experiments revealed that labeled PDC differentiated into cholangiocytes, but not into hepatocytes, in the chemically damaged liver. Nevertheless, EpCAM-positive PDC with genetic alterations gave rise to HCC after 8 months of chemical administration. PDC-derived HCC showed histologic characteristics of concomitant ductule-like structures resembling human cholangiolocellular carcinoma (CLC) and exhibited serial transitions from PDC-like CLC cells to hepatocyte-like HCC cells. The Wnt signaling pathway was specifically upregulated in the CLC components of PDC-derived HCC. Our findings provide direct experimental evidence that EpCAM-expressing PDC could be a cellular origin of HCC, suggesting the existence of stem/progenitor-derived hepatocarcinogenesis. Cancer Res; 77(22); 6131-43. ©2017 AACR.

A Multicenter Feasibility Study of EBUS-TBNA for Potentially Operable Non-Small Cell Lung Cancer: The JMTO LC07-02 Study (UMIN000001280).

BACKGROUND: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a standard procedure for the pathological evaluation of the mediastinal nodal (N2) status of lung cancer; however, its feasibility in potentially operable patients with suspicion of minimal N2 disease remains unestablished. PATIENTS AND METHODS: A prospective multicenter study was conducted to assess the feasibility of EBUS-TBNA in this setting. Patients with clinical stage IIIA-N2 non-small cell lung cancer (NSCLC) and mediastinal nodal enlargement on computed tomography (CT) were eligible; patients were ineligible when CT revealed bulky (> 3 cm in the long-axis diameter) N2 or multiple (≥ 3) station N2. If EBUS-TBNA revealed negative results, surgical staging procedures were mandatory. RESULTS: Among 20 eligible patients, EBUS-TBNA provided pathological confirmation of N2 disease (true-positive) in 12 patients. Among 8 patients with negative results with EBUS-TBNA, 4 patients were pathologically diagnosed as having N2 disease with surgical staging procedures (false-negative), and 4 were finally diagnosed as having non-N2 disease with nodal dissection by thoracotomy (true-negative). As a result, the sensitivity of EBUS-TBNA for N2 evaluation (primary endpoint) was 75.0% (95% confidence interval 47.6-92.7%). No grade 3-5 adverse event were documented. CONCLUSION: EBUS-TBNA is potentially safe and useful in the pathological evaluation of N2 status even in potentially operable NSCLC patients with suspicion of minimal N2 disease on preoperative CT.

Exophytic Tumor Growth After Incomplete Removal of Polypoid Malignant Melanoma of the Maxillary Gingiva: A Case Report and Review of the Literature.

Polypoid malignant melanoma of the oral cavity is extremely rare. This report describes the case of the 3-time occurrence of a polypoid malignant melanoma of the maxillary gingiva in an 84-year-old woman who had removed the primary tumor by herself. The second polypoid malignant melanoma was a black 7-cm pedunculated mass surrounded by pigmented mucosa. Histologically, the tumor exhibited an ulcerated surface lined by squamous cells and contained polygonal cells with brown-and-black pigmentation. The third polypoid malignant melanoma was observed at the same location 7 months after surgery; it was a black hemorrhagic mass approximately 1.5 cm. Histologic analysis showed morphologic findings that were similar to those observed in the second polypoid melanoma. The patient died of lung metastasis 28 months after the second surgery. This report also reviews the 5 previously reported cases of polypoid malignant melanoma of the oral cavity, all of which occurred in the upper jaw. In 2 cases, initial exophytic growth of the tumor before invasion of the submucosa and relatively early detection resulted in a good prognosis. However, in 1 case, amelanotic melanoma located in the periodontal tissues was clinically misdiagnosed as epulis. Therefore, immunostaining for S-100 and HMB-45 should be considered for nonpigmented epulis-like lesions, and wide surgical resection of primary polypoid malignant melanomas at an early stage should result in a favorable prognosis.

Intralymphatic histiocytosis comprises M2 macrophages in superficial dermal lymphatics with or without smooth muscles.

Intralymphatic histiocytosis represents a rare reactive disorder, which is characterized by the accumulation of macrophages within lymphatic vessels and observed predominantly in upper extremities. The infiltration and preferential M2 differentiation of macrophage are observed in chronic lymphedema, and lymphedema is considered a causative factor of intralymphatic histiocytosis. However, what causes accumulation of histiocytes in the lymphatic vessels remains unclear, and investigation regarding the characteristics of the macrophages has not been evaluated. We present a case of intralymphatic histiocytosis, in which immunohistochemical staining for both macrophages and lymphatic vessels was performed to evaluate the nature of macrophages within lymphatic vessels and to determine the causative factor. Aggregated macrophages were shown to be M2 macrophages positive for CD68, CD163 and CD206 but negative for inducible nitric oxide synthase. Thick lymphatic vessels positive for D2-40 and α-SMA in the superficial dermis were observed. We speculate that chronic lymphedema leads to hypertrophy of lymphatic vessels with smooth muscle in the superficial dermis, which may be a kind of malformation, and these lymphatic vessels produce some chemokines that induce intralymphatic aggregation of macrophages.

Syringomatous adenoma of the nipple: a case report.

INTRODUCTION: Syringomatous adenoma of the nipple is a very rare benign tumor. To the best of our knowledge, there are no reports of a syringomatous adenoma of the nipple metastasizing, although these tumors are known to infiltrate locally and to recur if not totally resected. CASE PRESENTATION: Our patient was a 41-year-old Japanese woman who complained of stiffness of her right nipple with abnormal discharge. Local resection of the tumor was performed. The pathological diagnosis was syringomatous adenoma of the nipple, and the resection margin was found to be positive. Accordingly, additional resection was recommended, but our patient did not allow another operation. After 1.5 years of careful follow-up, no local recurrence or distant metastasis has been observed. CONCLUSION: The optimal initial management of syringomatous adenoma of the nipple demands complete resection with histologically negative margins. However, from a cosmetic viewpoint, nipple-sparing resection could represent an alternative option for the treatment of syringomatous adenoma of the nipple.

Chronic lung injury by constitutive expression of activation-induced cytidine deaminase leads to focal mucous cell metaplasia and cancer.

Activation-induced cytidine deaminase (AID) is an enzyme required for antibody diversification, and it causes DNA mutations and strand breaks. Constitutive AID expression in mice invariably caused lung lesions morphologically similar to human atypical adenomatous hyperplasia (AAH), which can be a precursor of bronchioloalveolar carcinoma. Similar to AAH, mouse AAH-like lesion (MALL) exhibited signs of alveolar differentiation, judging from the expression of alveolar type II (AT2) cell marker surfactant protein C (SP-C). However, electron microscopy indicated that MALL, which possessed certain features of a mucous cell, is distinct from an AAH or AT2 cell. Although MALL developed in all individuals within 30 weeks after birth, lung tumors occurred in only 10%; this suggests that the vast majority of MALLs fail to grow into visible tumors. MALL expressed several recently described markers of lung alveolar regeneration such as p63, keratin 5, keratin 14, leucine-rich repeat containing G protein-coupled receptor 5 (Lgr5), and Lgr6. Increased cell death was observed in the lungs of AID transgenic mice compared with wild-type mice. Based on these observations, we speculate that MALL is a regenerating tissue compensating for cellular loss caused by AID cytotoxicity. AID expression in such regenerating tissue should predispose cells to malignant transformation via its mutagenic activity.

Exacerbation of intracranial aneurysm and aortic dissection in hypertensive rat treated with the prostaglandin F-receptor antagonist AS604872.

Intracranial aneurysm (IA) and aortic dissection are both complications of hypertension and characterized by degeneration of the media. Given the involvement of prostaglandin F2α and its receptor, FP, in extracellular matrix remodeling in a mouse model of pulmonary fibrosis, here we induced hypertension and IA in rats by salt loading and hemi-lateral ligation of renal and carotid arteries and examined effects of a selective FP antagonist, AS604872, on these vascular events. AS604872 significantly accelerated degeneration of the media in both cerebral artery and aorta as evidenced by thinning of the media and disruption of the elastic lamina and promoted IA and aortic dissection. Notably, AS604872 induced expression of pro-inflammatory genes such as E-selectin in lesions and significantly enhanced macrophage infiltration. Suppression of surface expression of E-selectin with cimetidine prevented macrophage infiltration and aortic dissection. Thus, AS604872 exacerbates vascular inflammation in hypertensive rats and facilitates IA and aortic dissection. These results demonstrate that both IA and aortic dissection are caused by chronic inflammation of the arterial wall, which is worsened by AS604872, cautioning that other FP antagonists may share such deleterious actions in vascular homeostasis and suggesting that AS604872 can be used to make models of these vascular diseases with extensive degeneration.

Kimura disease of the epiglottis: a case report and review of literature.

Kimura disease (KD) affecting an unusual site is a diagnostic challenge. We report herein the case of a 62-year-old Japanese woman who presented with swelling of the epiglottis, resulting in airway narrowing. Microscopically, biopsied and resected specimens both revealed lymphoid proliferation of a reactive immunophenotype, accompanied by vascular proliferation, eosinophilic infiltration, and stromal sclerosis. Adjunctive immunohistochemistry with immunoglobulin E in addition to laboratory and histological findings led us to seriously consider a diagnosis of KD. The patient underwent surgical removal with postoperative steroid therapy and has no evidence of recurrence. Our experience suggests that KD is potentially fatal as well as showing difficulty in the histological diagnosis when occurring in the upper respiratory tract, such as the epiglottis. A literature review disclosed that our case is the 11th case so far reported in this location, and that KD of the epiglottis did not show any male preponderance, as seen in other places.

Digestive disease management in Japan: a report on the 6th diagnostic pathology summer fest in 2012.

The 6th Diagnostic Pathology Summer Fest, held in Tokyo on August 25-26, 2012, opened its gates for everyone in the medical profession. Basic pathology training can contribute to the improvement of algorithms for diagnosis and treatment. The 6th Summer Fest with the theme 'Pathology and Clinical Treatment of Gastrointestinal Diseases' was held at the Ito International Research Center, The University of Tokyo. On August 25, 'Treatment of Early Gastrointestinal Cancer and New Guidelines' was discussed in the first session, followed by 'Biopsy Diagnosis of Digestive Tract: Key Points of Pathological Diagnosis for Inflammation and Their Clinical Significance' in the second session. On August 26, cases were discussed in the third session, and issues on pathological diagnosis and classification of neuroendorcrine tumor in the fourth session. The summaries of speeches and discussions are introduced along with the statements of each speaker. This meeting was not a formal evidence-based consensus conference, and 20 experts gave talks on their areas of specialty. Discussion was focused on how the management strategy should be standardized on the algorithm of patient care.

GEP100-Arf6-AMAP1-cortactin pathway frequently used in cancer invasion is activated by VEGFR2 to promote angiogenesis.

Angiogenesis and cancer invasiveness greatly contribute to cancer malignancy.Arf6 and its effector, AMAP1, are frequently overexpressed in breast cancer, and constitute a central pathway to induce the invasion and metastasis. In this pathway, Arf6 is activated by EGFR via GEP100. Arf6 is highly expressed also in human umbilical vein endothelial cells (HUVECs) and is implicated in angiogenesis. Here, we found that HUVECs also highly express AMAP1, and that vascular endothelial growth factor receptor-2 (VEGFR2) recruits GEP100 to activate Arf6. AMAP1 functions by binding to cortactin in cancer invasion and metastasis. We demonstrate that the same GEP100-Arf6-AMAP1-cortactin pathway is essential for angiogenesis activities, including cell migration and tubular formation, as well as for the enhancement of cell permeability and VE-cadherin endocytosis of VEGF-stimulated HUVECs. Components of this pathway are highly expressed in pathologic angiogenesis, and blocking of this pathway effectively inhibits VEGF- or tumor-induced angiogenesis and choroidal neovascularization. The GEP100-Arf6-AMAP1-cortactin pathway, activated by receptor tyrosine kinases, appears to be common in angiogenesis and cancer invasion and metastasis, and provides their new therapeutic targets.