Idiopathic myointimal hyperplasia of mesenteric veins: Rare case of ischemic colitis mimicking inflammatory bowel disease

Idiopathic myointimal hyperplasia of mesenteric veins (IMHMV) is a rare and poorly understood ischemic colitis that occurs in the rectosigmoid colon of predominantly young, previously healthy, male patients. A 76‐year‐old Japanese man presented to our hospital with a 1‐year history of worsening diarrhea, lower abdominal pain, and weight loss (−6 kg). Laboratory evaluation revealed white blood cell count of 13 200/μL, C‐reactive protein level of 2.0 mg/dL (normal range, 0.0–0.3), and negative results for stool culture (including Clostridium difficile). Colonoscopy showed circumferential and edematous narrowing of the sigmoid colon with deep longitude ulceration. Biopsy was done and examination of the specimen demonstrated no specific ischemia. The patient was treated with bowel rest, antibiotics, and i.v. fluids; however, his symptoms worsened. Finally, sigmoidectomy was carried out. Histological examination demonstrated significant myointimal hyperplasia of mesenteric veins leading to thickening and stenosis of the venous lumen. Therefore, the final diagnosis was IMHMV. Three months following sigmoidectomy, he was asymptomatic.     

Molecular evidence for multicentric development of thyroid carcinomas in patients with familial adenomatous polyposis

Familial adenomatous polyposis is characterized by multiple colorectal adenomas and an increased incidence of colorectal carcinomas. Patients also develop various extracolonic tumors, of which, thyroid carcinoma is common in young females. The occurrence of multiple carcinomas in one thyroid is frequently observed, although some carcinomas are solitary. To clarify whether each carcinoma develops independently or metastatically spreads from the first one formed, we analyzed the adenomatous polyposis coli (APC) gene mutation in each carcinoma. We found that each carcinoma had a different somatic mutation of the APC gene. This is molecular confirmation for the multicentric development of thyroid carcinomas in familial adenomatous polyposis through biallelic inactivation of the APC gene.     

CD5 expression in thymic carcinoma.

To determine the differences between the cellular characteristics of thymic carcinoma and thymoma, immunohistochemical analysis with lymphocyte markers (CD1a, 3, 4, 5, 8, 10, 20, 21, 25, 30, 57, and 72) was performed on 23 thymic epithelial tumors other than lymphocytic thymoma: overt thymic carcinoma (OC, n = 7), atypical thymoma (n = 5), and typical thymoma (epithelial or mixed thymoma, n = 11). Among the surface antigens examined, CD5, a type of receptor molecule that signals cell growth in T cells, was expressed in neoplastic epithelial cells of the thymus, in OC (seven of seven) and atypical thymoma (two of five), but not in typical thymoma. Double labeling immunofluorescence demonstrated expression of CD5 in cytokeratin-positive cells. The CD5 molecule extracted from an OC tumor showed the same molecular size as that in the spleen, but CD72, a ligand of CD5 on the surface of B cells, was not found in the epithelial cells of OC or atypical thymoma. Expression of CD5 was not observed in carcinomas of other organs, such as lung (n = 15), breast (n = 4), esophagus (n = 6), stomach (n = 6), colon (n = 9), and uterine cervix (n = 3). CD5 is closely related to morphological changes in thymic epithelial tumors and may play a role in the evolution of OC through receptor-ligand interaction.     

Calcified liver metastases from a non-functioning pancreatic neuroendocrine tumor

Neuroendocrine tumors consist of a spectrum of malignancies that arise from neuroendocrine cells throughout the body. Pancreatic neuroendocrine tumors are rare tumors, with an incidence of 3.65 per 100,000 individuals per year, and they account for 1–2 % of all pancreatic neoplasms. A non-functioning pancreatic neuroendocrine tumor with multiple liver metastases with calcifications was diagnosed in a 43-year-old female with diabetes mellitus. Early phase-enhanced computed tomography (CT) showed a hypovascular mass in the pancreatic body and tail with calcifications and multiple liver metastatic masses with calcifications. Percutaneous liver biopsy showed homogenous nuclear chromatins and tumor cells with acidophilic cytoplasm against the hyaline interstitium, and a non-functioning pancreatic neuroendocrine tumor was diagnosed. An interesting clinical image of a metastasis from a pancreatic neuroendocrine tumor is presented in which multiple liver tumors were accompanied by dystrophic calcifications. CT and percutaneous liver biopsy play an important role in the diagnosis of a non-functioning pancreatic neuroendocrine tumor, and are valuable diagnostic methods in planning treatment.     

Spermatic cord metastases from gastric cancer with elevation of serum hCG-beta: a case report

Spermatic cord metastases from gastric cancer are rare. We here document a case involving a gastric cancer that mimicked primary testicular tumor because of elevation of the serum human chorionic gonadotropin-beta (hCG-beta). The possibility of metastasis or recurrence of prior malignancies should therefore be considered when the clinical features described here are encountered, although elevation of hCG-beta is rare with tumors other than those in testis.     

Extraosseous Benign Notochordal Cell Tumor Originating in the Lung: A Case Report

Benign notochordal cell tumors (BNCTs) are tumors originating in the axial skeleton, where chordomas occur. Although very rare, some cases of extraosseous chordoma, such as in the soft tissue and lungs, have been reported. We report a case of a primary tumor showing the notochordal characteristics of BNCTs within the axial skeleton.An asymptomatic 57-year-old woman presented with an abnormal shadow on her chest radiograph; chest computed tomography revealed a well-defined round nodule. The resected sample tissue contained a jelly-like small nodule. Histologically, it was identified as a BNCT, based on minimal nuclear atypia, extremely low mitotic activity within the tumor cells lying in a sheet-like arrangement, and focal immunopositivity for brachyury.This is the third case report of BNCT originating in the lungs; BNCTs are considered asymptomatic tumors that are identified by using highly developed chest imaging technology; however, our findings also suggest that these notochordal tumors may potentially originate from extraosseous sites that lack ideal precursor cells. Our case suggests that notochordal tumors can arise from organs that are unrelated to known notochordal development.     

Thymic carcinoid accompanied by elevation of serum gastrin-releasing peptide precursor; report of a case

A 74-year-old male was admitted with an abnormal mediastinal shadow. Computed tomography (CT) and magnetic resonance imaging (MRI) of the thorax showed an anterior mediastinal mass without invasion to the ascending aorta and pulmonary artery. In addition, serum gastrin-releasing peptide precursor (Pro GRP) was increased (60.6 pg/ml, normal range <46 pg/ml). Video-assisted thoracoscopic biopsy demonstrated that the mass was thymic carcinoid. Therefore, median sternotomy was performed to facilitate thymectomy, including the tumor with partial resection of the left upper lobe and pericardium. The patient received mediastinal irradiation postoperatively. The postoperative serum level of Pro GRP decreased to the normal limit 6 months later. Although a biological relationship between Pro GRP and thymic carcinoid was not proven, it might be useful marker for detecting tumor recurrence.     

Differences in histological features and PD-L1 expression between sporadic microsatellite instability and Lynch-syndrome-associated disease in Japanese patients with colorectal cancer

Background

The field of immunotherapy has recently focused on cancers with microsatellite instability (MSI). These cancers include both Lynch-syndrome-associated tumors, which are caused by mismatch repair (MMR) germline mutations, and sporadic MSI tumors, which are mainly attributed to MLH1 promoter methylation. The present study aimed to clarify differences in the histological and PD-L1 expression profiles between these two types of MSI cancers in Japanese patients.

Methods

Among 908 cases of colorectal cancer treated via surgical resection from 2008 to 2014, we identified 64 MSI cancers, including 36 sporadic MSI and 28 Lynch-syndrome-associated cancers, using a BRAF V600E mutation analysis and MLH1 methylation analysis. Of the latter subgroup, 21 (75%) harbored MMR germline mutations.

Results

The following were more frequent with sporadic MSI than with Lynch syndrome associated cancers: poor differentiation (50.0 vs. 7.1%, P = 0.0002), especially solid type (30.6 vs. 3.6%, P = 0.0061); medullary morphology (19.4 and 0%, P = 0.015), Crohn-like lymphoid reaction (50.0 vs. 25.0%, P = 0.042), and PD-L1 expression (25.0 vs. 3.6%, P = 0.034). However, the groups did not differ in terms of the mean invasive front and intratumoral CD8-positive cell densities. In a logistic regression analysis, PD-L1 expression correlated with poor differentiation (odds ratio: 7.65, 95% confidence interval: 1.55–37.7, P = 0.012), but not with the difference between sporadic MSI cancer and Lynch-syndrome-associated cancer (odds ratio: 4.74, 95% confidence interval: 0.50–45.0, P = 0.176).

Conclusions

Therefore, compared with Lynch-syndrome-associated cancers, sporadic MSI cancers are more frequently solid, poorly differentiated medullary cancers that express PD-L1.

     

A case report of cutaneous melanocytoma with CRTC1‐TRIM11 fusion: Is CMCT distinct from clear cell sarcoma of soft tissue?

Pathological diagnosis of dermal melanocytic tumors is often problematic owing to histological resemblance. Recently, cutaneous melanocytoma with CRTC1‐TRIM11 (CMCT) was added to this category. However, only six cases have been reported so far. We herein present a case of a 77‐year‐old Japanese man with CMCT. The patient presented a nodule in the right thigh and underwent surgical resection. Histological examination indicated a well‐demarcated 6 × 5 mm‐sized tumor nodule in the dermis and subcutis. The tumor was amelanotic, consisting of uniform nests and fascicles of spindled, or epithelioid cells. The melanocytic nature was evident by immunohistochemistry. The CRTC1‐TRIM11 fusion was detected by TRIM11 immunostaining, chromogenic in situ hybridization, and RT‐PCR/direct sequencing. He has been free from the tumor for 1 year after additional resection. The main differential diagnosis of CMCT includes primary and metastatic dermal malignant melanomas (MM) and dermal/subcutaneous clear cell sarcoma (CCS). Additionally, histological overlap with paraganglioma‐like dermal melanocytic tumor was considered. Although some investigators argue that CMCT is a variant of CCS, we think it should be separated from CCS, and subcutaneous/dermal CCS should be confined to tumors with EWSR1‐ATF1/ CREB1 fusion. However, longer follow‐up and more case studies are needed for revealing the true prognosis of CMCT.