A pathological complete response after nivolumab plus ipilimumab therapy for DNA mismatch repair-deficient/microsatellite instability-high metastatic colon cancer: A case report.

The standard treatment for colorectal cancer has always been surgery and chemotherapy, which may be used in combination to treat patients. Immune checkpoint inhibitors have been a significant advancement in the standard treatment of metastatic, unresectable colorectal cancer with deficient mismatch repair. However, little information is available about their use in neoadjuvant and conversion settings with only a few case reports and only one phase 2 trial. The present study reports the case of a large, locally advanced right-sided metastatic deficient mismatch repair/microsatellite instability-high colon cancer, which showed a pathological complete response after combination treatment with nivolumab and ipilimumab. To the best of our knowledge, resected metastatic colon cancer with a pathological complete response after treatment using dual immune checkpoint inhibitors has not been previously reported. Overall, this case report suggests the use of immune checkpoint inhibitors before colorectal surgery.

Distant Metastasis after Surgery for Encapsulated Papillary Carcinoma of the Breast: A Case Report.

In the absence of clear interstitial invasion, encapsulated papillary carcinoma (EPC) of the breast may be attributed to an extremely good prognosis if handled similarly to ductal carcinoma in situ (DCIS) with suitable local treatment. Here, we report our experience with a case of EPC of the breast that presented with carcinomatous pleuritis and lymphangitis carcinomatosa postoperatively, which rapidly resulted in a poor outcome. A 67-year-old woman was diagnosed with DCIS of the left breast and underwent left partial mastectomy and sentinel lymph node biopsy. EPC was diagnosed because the pathological examination showed no sign of interstitial infiltration. Postoperative radiation therapy was performed. Five years and 9 months postoperatively, the patient began experiencing cough and shortness of breath on exertion. Imaging showed right pleural effusion and consolidation of the lung field, but nothing suggesting local recurrence in the preserved left breast, local lymph nodes, or opposite breast was observed. Postoperative recurrence of breast cancer, carcinomatous pleuritis, and lymphangitis carcinomatosa were diagnosed based on the results of pleural fluid cytology. One month later, multiple brain metastases were found, and the patient died of the primary disease 5 months after recurrence. After surgery for EPC without clear interstitial infiltration, there was a small possibility of a poor outcome from distant metastasis. Therefore, although distant metastasis is uncommon, regular examination and testing should be performed.

Mass-forming hepatic cryptococcosis: a mimicker of metastatic tumors.

This report provides the first imaging report of isolated intrahepatic cryptococcosis. An 83-year-old man was incidentally pointed out of hepatic nodules. CT revealed four well-defined nodules of 21 mm, 15 mm, 7 mm, and 5 mm in diameter without contrast enhancement. Two nodules displayed central hyperattenuation and the others were totally hyperattenuating. MRI showed that the nodules were hypointense relative to normal liver parenchyma on T1- and T2-weighted images. 18F-FDG PET imaging revealed no obvious increased uptake of nuclear species into the liver nodules. Partial resection of the three largest hepatic nodules was performed based on a preoperative diagnosis of hepatic metastasis from known sigmoid colon cancer. All three resected nodules were composed mainly of necrotic tissue with peripheral histiocytic aggregates and numerous yeast-like cells. The final diagnosis was hepatic cryptococcosis.

A case of small bowel adenocarcinoma wherein nivolumab conferred temporary benefit in disease control.

Small bowel adenocarcinomas are rare. There is no definite consensus as to whether they should be treated in a manner similar to gastric or to colon cancer. We report the case of a young woman with a primary jejunal adenocarcinoma, bilateral ovary metastases, and peritoneal dissemination. First- and second-line chemotherapy for the gastric cancer failed. She was then treated with the immune checkpoint inhibitor nivolumab and had temporary improvement in her condition. To the best of our knowledge, this is the first case wherein nivolumab has been used to treat small bowel adenocarcinoma.

HER2-Positive Conversion in a Metastatic Liver Focus in Late Recurrent Breast Cancer.

Late recurrence of estrogen receptor (ER) positive breast cancer is common. When tissues from a recurrent or metastatic focus are available, re-evaluation of ER, progesterone receptor (PgR), and human epidermal growth factor receptor 2 (HER2) status is recommended for treatment selection. This case report describes a 59-year-old woman who underwent surgery for left breast cancer, with a histopathological diagnosis of invasive ductal carcinoma (pathological stage T2N1aM0 Stage IIB, ER positive, PgR positive and HER2 negative). A health check-up 16 years after surgery revealed multiple hepatic mass lesions, and the patient was referred to our hospital for tests. Based on computed tomography, intrahepatic bile duct cancer or metastatic hepatic tumors were suspected, and a liver biopsy was performed. The histopathological diagnosis was a poorly differentiated adenocarcinoma (ER negative, PgR negative and HER2 positive), and the distinction from poorly differentiated intrahepatic bile duct cancer was difficult. Fluorodeoxyglucose (FDG)-positron emission tomography revealed FDG accumulation in the patient's bones and soft tissues, in addition to the hepatic tumors. The patterns and finding of metastasis were compatible with breast cancer recurrence, and the patient was diagnosed with postoperative recurrence of left breast cancer. Pertuzumab, trastuzumab, and docetaxel were started, and the therapeutic effect was assessed as a partial response. It was evident that in this case, the expression of hormone receptors and HER2 differed between the primary focus and the recurrence foci, and this contributed to the treatment strategy. Whenever possible, a biopsy should be performed for lesions that are suspected to be distal metastases.

Lymphoplasmacytic Lymphoma Presenting with Diarrhea and Joint Pain Which was Successfully Diagnosed by an MYD88 Mutation Analysis.

A 55-year-old man presented to our department with diarrhea, weight loss, fatigability, and polyarthralgia. Blood tests revealed elevated soluble interleukin-2 receptor levels and IgG-type M protein positivity, without any findings that were suggestive of collagen disease. After computed tomography (CT) detected enlarged lymph nodes in the abdominal para-aortic region, lymphoma was suspected. CT-guided needle biopsy of the lymph node did not help to achieve a definitive diagnosis; however, a bone marrow test showed the pathological features of B-cell lymphoma. A genetic examination detected a MYD88 L265P mutation; the mutation analysis was valuable in diagnosing lymphoplasmacytic lymphoma in a IgM-type M protein-negative patient.

Malignant transformation of hyperplastic gastric polyps: An immunohistochemical and pathological study of the changes of neoplastic phenotype.

In spite of the evidence that the malignant transformation of gastric hyperplastic polyps (HPs) is a rare event, it must always be taken into account during diagnosis. The aim of the current study was to clarify the mechanism of the malignant transformation of gastric hyperplasia polyps, with focus on phenotypic expression, cell proliferation and p53 overexpression. Immunohistochemistry for mucin phenotypic markers, including MUC1, MUC2, MUC5AC, MUC6, tight junction factors (claudin-3, -4 and -18), an intestinal phenotypic marker [caudal type homeobox 2 (Cdx2)], Ki-67 proliferative index and p53 overexpression, was performed on archival specimens of gastric polyps excised from six patients. Histologically, the intermingled components of several lesions were present in these polyps. Furthermore, the cancer components were predominantly differentiated adenocarcinoma. Immunohistochemically, all hyperplastic components expressed MUC5AC, but did not exhibit positivity for MUC2. Additionally, the majority of hyperplastic components were immunonegative for claudin-3, while claudin-3 positivity was observed in the majority of areas of dysplasia and carcinoma. Expression of claudin-4 was also observed in the majority of cases and claudin-18 was preserved in the hyperplastic, dysplastic and adenocarcinomatous lesions of all cases. Nuclear accumulation of Cdx2 was detected in almost all the samples with dysplasia and carcinoma, while nuclear p53 was detected in 24-80% of the dysplastic areas and >85% of the cancer components. The Ki-67 labeling index appeared to correlate with neoplastic progression. The observations provided evidence that the mechanism underlying malignant transformation of gastric HPs may occur by multistep carcinogenesis, such as the hyperplasia-adenoma (dysplasia)-adenocarcinoma sequence, and these neoplastic cells may acquire various phenotypes during this process.

A logistic regression predictive model and the outcome of patients with resected lung adenocarcinoma of 2 cm or less in size.

Diagnostic criteria to identify small lung adenocarcinomas that relapse after resection have yet to be established. For this purpose, we developed a mathematical logistic model in the present study. We collected data for patients with lung adenocarcinoma of 2 cm or less in size: the original cohort comprised 28 men and 25 women and the validation cohort comprised 11 men. By entering five clinicopathological factors (vascular invasion, lymphatic permeation, histological subtype, papillary carcinoma component, and smoking status) into the logistic model, we calculated a predictive function for relapse after surgery. The obtained predictive function accurately classified the patients into a recurrence or non-recurrence group: the overall accuracy of the predictive model for recurrence established from the male patients in the original cohort was 86%. Our predictive model is, however, currently limited to male patients only, because the original cohort included only one female patient with relapse. By applying the logistic model to the validation cohort, six patients were classified into a recurrence group and the other five into a non-recurrence group: four of the six patients in a recurrence group had relapsed, while all five patients in the non-recurrence group were well during their follow-up periods. Although the predictive ability of the logistic model did not reach a statistical significance (P=0.0606), nine of the 11 (82%) patients in the validation cohort were correctly classified. Consequently, using a logistic predictive model consisting of the five clinicopathological factors might enable us to predict the recurrence of resected small-sized lung adenocarcinomas in male patients.

In situ observation of germinal center cell apoptosis during a secondary immune response.

Germinal centers are highly organized anatomic structures essential for the clonal expansion of germinal center (GC) B-cells and associated somatic hypermutation, isotype switching, selection of the high-affinity B-cells (affinity maturation), and elimination of irrelevant or autoreactive clones. The identification of cellular interactions and regulatory mechanisms controlling apoptosis within GCs is essential for a complete understanding of the cellular and molecular dynamics of the GC reaction. We performed a kinetic analysis of the apoptotic activity occurring within GCs of draining lymph nodes of mice immunized with sheep red blood cells (SRBC) after secondary stimulation. The apoptotic activity of GC cells can be divided into three distinct phases : 1) initial phase (within the first days after immunization), 2) reactive phase (from the 5th day to 15th day after secondary immunization), and 3) late phase (after the 15th day). Apoptosis decreased shortly after secondary immunization followed by an increase to peak after an additional 10 days. Finally, apoptosis of GC cells decreased to basal levels. Administration of apoptosis inhibitors decreased the amount of apoptosis during the reactive phase. These results suggest that the reactive phase may be the critical period in which clonal selection and cellular differentiation to antibody forming cells take place.

Immunohistochemical recognition of human follicular dendritic cells (FDCs) in routinely processed paraffin sections.

A number of monoclonal antibodies (MAbs) that recognize human follicular dendritic cells (FDCs) have been identified. Although some of them have already been applied individually in routine immunolabeling using formalin-fixed paraffin sections for diagnostic and experimental purposes, many antibodies are still employed only for immunolabeling using cryostat sections or particularly processed sections because they have been thought unsuitable for routine sections. A comprehensive examination re-evaluating their suitability in paraffin sections has not been reported. Accordingly, there is limited ability to examine the immunopathological contribution or diagnostic value of FDCs using routinely processed specimens or archived materials. In this study a broad panel of antibodies was systematically applied to the immunolabeling of paraffin sections of reactive tonsils or lymph nodes, in combination with advanced antigen retrieval (AR) techniques. Several antibodies, including Ki-M4p, X-11, 12B1, CNA.42, 1F8/BU32 (anti-CD21), BU38/1B12 (anti-CD23), Ber-MAC-DRC/To5 (anti-CD35), 1.4C3 (anti-CD106), NGFR5 (anti-nerve growth factor receptor p75), IIH6 (anti-CD55), 55K-2 (anti-fascin), and anti-S100 protein alpha-chain, were found to label FDCs in routine sections when combined with suitable AR techniques. Our results are easily adaptable for routine practice and provided useful suggestions concerning the immunopathological behavior and diversity of the particular cells.