Deep learning-based approach to the characterization and quantification of histopathology in mouse models of colitis.

Inflammatory bowel disease (IBD) is a chronic immune-mediated disease of the gastrointestinal tract. While therapies exist, response can be limited within the patient population. Researchers have thus studied mouse models of colitis to further understand pathogenesis and identify new treatment targets. Flow cytometry and RNA-sequencing can phenotype immune populations with single-cell resolution but provide no spatial context. Spatial context may be particularly important in colitis mouse models, due to the simultaneous presence of colonic regions that are involved or uninvolved with disease. These regions can be identified on hematoxylin and eosin (H&E)-stained colonic tissue slides based on the presence of abnormal or normal histology. However, detection of such regions requires expert interpretation by pathologists. This can be a tedious process that may be difficult to perform consistently across experiments. To this end, we trained a deep learning model to detect 'Involved' and 'Uninvolved' regions from H&E-stained colonic tissue slides. Our model was trained on specimens from controls and three mouse models of colitis-the dextran sodium sulfate (DSS) chemical induction model, the recently established intestinal epithelium-specific, inducible Klf5ΔIND (Villin-CreERT2;Klf5fl/fl) genetic model, and one that combines both induction methods. Image patches predicted to be 'Involved' and 'Uninvolved' were extracted across mice to cluster and identify histological classes. We quantified the proportion of 'Uninvolved' patches and 'Involved' patch classes in murine swiss-rolled colons. Furthermore, we trained linear determinant analysis classifiers on these patch proportions to predict mouse model and clinical score bins in a prospectively treated cohort of mice. Such a pipeline has the potential to reveal histological links and improve synergy between various colitis mouse model studies to identify new therapeutic targets and pathophysiological mechanisms.

KLF5 protects the intestinal epithelium against Th17 immune response in a murine colitis model.

Inflammatory bowel disease (IBD) is a chronic illness characterized by dysregulated immune cascades in the intestines, in which the Th17 immune response plays an important role. We demonstrated that mice with intestinal epithelium-specific deletion of Krüppel-like factor 5 (Klf5) developed Th17-dependent colonic inflammation. In the absence of KLF5, there was aberrant cellular localization of phosphorylated STAT3, an essential mediator of the Th17-associated cytokine, IL-22, which is required for epithelial tissue regeneration. In contrast, mitigation of IL-17A with anti-IL-17A neutralizing antibody attenuated colitis in Klf5-deficient mice. There was also a considerable shift in the colonic microbiota of Klf5-deficient mice that phenocopied human IBD. Notably, the inflammatory response due to Klf5 deletion was alleviated by antibiotic treatment, implicating the role of microbiota in pathogenesis. Finally, human colitic tissues had reduced KLF5 levels when compared with healthy tissues. Together, these findings demonstrated the importance of KLF5 in protecting the intestinal epithelium against Th17-mediated immune and inflammatory responses. The mice described herein may serve as a potential model for human IBD.

Intratumoral Budding and Tumor Microenvironment in Pretreatment Rectal Cancer Biopsies Predict the Response to Neoadjuvant Chemoradiotherapy.

Tumor budding at the invasive tumor front (peritumoral budding) is an established prognostic factor in colorectal cancer. However, the significance of intratumoral budding (ITB) in pretreatment biopsies is still uncertain. Our study aims to investigate the association of ITB and tumor microenvironment in pretreatment rectal cancer biopsies with pathologic response to neoadjuvant chemoradiotherapy. Pretreatment biopsies of low-grade rectal cancer from 37 patients who underwent resection after neoadjuvant chemoradiotherapy were retrospectively reviewed to evaluate ITB, type of tumor stroma, and intraepithelial lymphocytes. ITB was counted on a single hotspot in 1 HPF upon pan-keratin immunohistochemical staining. Intraepithelial lymphocytes was graded semiquantitatively as "absent" (≤2/HPF) or "present" (>2/HPF). The tumor stroma was classified as either immature type or maturing type. In pretreatment biopsies, ITB was observed in 34/37 patients (92%). High-grade ITB was significantly associated with a poor pathologic response to neoadjuvant chemoradiotherapy (tumor regression score 2 to 3, P<0.001; and higher posttreatment T stage, P=0.002). Immature type of stroma was significantly associated with both high-grade ITB in biopsies (P=0.02) and a poor pathologic response to neoadjuvant chemoradiotherapy (tumor regression score 2 to 3, P=0.005). In multivariate analysis, ITB and the type of stroma remained the significant parameters for prediction of response to neoadjuvant treatment. Our study indicates that ITB and tumor microenvironment in pretreatment biopsies are strong predictors of response to neoadjuvant chemoradiotherapy, which may assist risk stratification and clinical management in rectal cancer patients.

Distinct pathways of pathogenesis of intraductal oncocytic papillary neoplasms and intraductal papillary mucinous neoplasms of the pancreas.

Intraductal oncocytic papillary neoplasm (IOPN) of the pancreas is classified as a variant of intraductal papillary mucinous neoplasm (IPMN) in the WHO guidelines. However, the neoplastic cells of IOPNs are unique, with distinctive architecture/oncocytic cytoplasm. Although molecular/immunohistochemical features of other IPMN variants have been extensively studied, those of IOPNs have not been well characterized. Expression profile of antibodies associated with genetic alterations previously described for ductal adenocarcinomas (DAs) and IPMNs (SMAD4/ß-catenin/p53/mesothelin/claudin-4) as well as antibodies to mucins and differentiation markers [MUC1/MUC2/MUC5AC/MUC6/CDX2/hepatocyte paraffin-1 (HepPar-1)] was investigated in 24 IOPNs and 22 IPMNs to assess the similarities/differences between these tumors. Expression of mesothelin and claudin-4 was dissimilar between these tumor types: A higher proportion of IOPNs labeled with mesothelin [21/24 (87.5 %) of IOPNs, 6/22 (27 %) of IPMNs, p < 0.001], while the reverse was true for claudin-4 [2/23 (9 %) of IOPNs, 9/22 (41 %) of IPMNs, p = 0.01]. The results of immunolabeling for SMAD4/ß-catenin/p53 were similar in both: None of the cases showed SMAD4 loss in the intraductal components, and only 1/21 (5 %) of IOPNs and 2/22 (9 %) of IPMNs revealed abnormal ß-catenin expression (p = 0.49). Nuclear p53 accumulation was seen mostly in architecturally complex/high-grade dysplasia areas in both. Immunolabeling for MUC proteins showed that almost all lesions expressed MUC5AC. Twelve of the 24 (50 %) IOPNs and 6/22 (27 %) of IPMNs (p = 0.11) labeled for MUC1, whereas 7/24 (29 %) of IOPNs and 10/22 (45 %) of IPMNs labeled for MUC2 (p = 0.25). MUC6 was expressed in 8/9 (89 %) of IOPNs (strong) and 6/21 (29 %) of IPMNs (weak) (p = 0.002). Fourteen of the 23 (61 %) IOPNs and 4/22 (18 %) of IPMNs labeled for HepPar-1 (p = 0.003). These results show that IOPNs have distinct immunoprofile and provide support for the proposition that IOPN is a distinct entity developing through a mechanism different from other pancreatic ductal neoplasms.

Pleomorphic pancreatic endocrine neoplasms: a variant commonly confused with adenocarcinoma.

Most pancreatic endocrine neoplasms (PENs) have distinctive endocrine growth patterns and uniform nuclear morphology; they are regarded as relatively low-grade tumors. Significant nuclear pleomorphism is a feature that may raise concerns about aggressive behavior or even obscure the endocrine nature of the neoplasm. Eight PENs exhibiting marked nuclear pleomorphism (>20% of the tumor cells) were identified during a review of 136 PENs (5.9%) from the pathology files of Memorial Sloan-Kettering Cancer Center. The histologic, immunohistochemical, ultrastructural (4 cases), and clinical features were reviewed. There were 6 males and 2 females ranging from 30 to 69 years (mean, 55 years). The tumors averaged 5.8 cm (range, 1.5-14 cm). Six tumors (75%) were initially misdiagnosed in 5 cases as adenocarcinoma and in one as solid-pseudopapillary tumor; in 2 cases, the misdiagnosis was based on fine needle aspiration cytology and in 4 on histologic examination. The architectural features of the tumors resembled those of other PENs, but the nuclei were markedly enlarged, irregularly shaped, and hyperchromatic, with frequent bizarre forms. Cells with pleomorphic nuclei also generally had abundant cytoplasm, sometimes with large perinuclear glassy inclusions. The mitotic rate was not elevated compared with other PENs, averaging 1.9 (range, 0-7) per 50 high power fields. Immunohistochemical findings were (number positive/number stained): chromogranin (8 of 8), synaptophysin (7 of 8), progesterone receptor (4 of 7), CD99 (2 of 5), S-100 protein (3 of 7), and p53 (0 of 6). Scattered cells expressed peptide hormones in a minority of cases. By electron microscopy, abundant dense core granules were identified, in some cases embedded within perinuclear arrays of intermediate filaments. Six patients underwent curative resection; at follow-up, 4 were free of disease at 11, 13, 30, 112 months (mean, 42 months), 1 developed liver metastases at 77 months and was alive with disease at 94 months, and 1 was lost to follow-up. Two patients had unresectable tumors and were alive with disease at 10 and 78 months. Striking nuclear pleomorphism may occur in otherwise typical PENs and commonly causes difficulties in the distinction from adenocarcinoma. There does not appear to be prognostic significance to these nuclear changes, and the morphologic features of pleomorphic PENs otherwise resemble those of their conventional counterparts.

Malignant fibrous histiocytoma arising within a bone infarct in a patient with sickle cell trait.

Sarcoma associated with osteonecrosis or bone infarction is a rare but well-documented pathological event. In this report, a 69-year-old man with sickle cell trait presented with malignant fibrous histiocytoma (MFH) in his distal tibia. The resected tumor was found in association with a large medullary infarct that extended 10 cm proximal from the tumor site. Bone infarcts can be caused by a number of processes including corticosteroid overuse, alcoholism, dysbarism, and hemoglobinopathies such as sickle cell disease. Patients with sickle cell anemia often develop osteonecrosis, but osteonecrosis has also been reported in people with sickle cell trait, albeit much more rarely. Our patient is only the third reported case of infarct-related bone sarcoma in a patient with sickle cell trait. Bone infarction may be a rare though serious consequence of sickle cell trait.

Combined hepatocellular-cholangiocarcinoma: a histopathologic, immunohistochemical, and in situ hybridization study.

Combined hepatocellular-cholangiocarcinoma (CHC) forms a small but significant proportion of primary liver carcinomas. However, its diagnostic features are not well established, and this has possibly contributed to the variability in its reported clinical outcome in the literature. Many such tumors with features intermediate between hepatocellular carcinoma and cholangiocarcinoma (CC) may have been considered CC in the past based on positivity for "biliary differentiation" cytokeratins and the lack of availability of highly sensitive and specific hepatocellular markers. The utility of in situ hybridization for albumin mRNA, a recently available sensitive and specific hepatocellular marker, has not been reported in CHC. We investigated 27 CHCs with regard to their histomorphologic spectrum and association of these morphologies with immunohistochemical staining for different cytokeratins (CK7, CK19, and CK20; AE1; Cam 5.2), epithelial membrane antigen, polyclonal carcinoembryonic antigen and alpha-fetoprotein, and in situ hybridization for albumin mRNA. All 27 tumors contained areas morphologically intermediate between hepatocellular carcinoma and CC (transitional-type tumors), and in each case such areas formed at least 25% of the tumor. Nine (33%) tumors showed areas with "antler-like" morphology, a feature not previously described in CHC. Twenty-two of 23 tumors (96%) showed positive signals on in situ hybridization for albumin mRNA. Positivity for both hepatocellular (albumin mRNA) and biliary (keratin immunohistochemical profile) markers confirmed the light microscopic impression of biphenotypic differentiation in these tumors. Immunohistochemical positivity for all cytokeratins (except CK7) and epithelial membrane antigen, as well as the expression of albumin mRNA by in situ hybridization, did not show significant differences between hepatocellular carcinoma and CC-like areas. Based on the cytokeratin profile and results on polyclonal carcinoembryonic antigen/alpha-fetoprotein alone, many such tumors would be classified as CC. However, the positivity for albumin mRNA by in situ hybridization proves that such an interpretation would not have been accurate. Clinically, CHCs showed many differences from pure hepatocellular carcinoma, including the absence of cirrhosis (0 of 27), rarity of serum hepatitis B or C marker positivity (4 of 27), and normal to only mildly elevated serum alpha-fetoprotein levels (median 187 ng/mL). The tumor followed an aggressive clinical course, with overall 3-and 5-year survival rates of 30% and 18%, and in the resected cases of 38% and 24%, respectively.

Fine needle aspiration cytology of dermatofibrosarcoma protuberans presenting as a breast mass. A case report.

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is an uncommon cutaneous soft tissue neoplasm with a tendency to recur but rarely metastasize. It occurs at almost any site but usually in the trunk and extremities. DFSP mimicking a primary breast lesion has not been reported before. CASE: A 30-year-old female presented with an eight-month history of a breast mass that was aspirated, revealing a spindle cell neoplasm. The diagnosis of DFSP was made on excisional biopsy. CONCLUSION: The diagnosis of DFSP may be problematic, especially when it presents clinically as a primary breast lesion.

Intraductal papillary-mucinous neoplasms of the pancreas: an analysis of in situ and invasive carcinomas in 28 patients.

BACKGROUND: Intraductal papillary-mucinous neoplasms (IPMNs) of the pancreas are intraductal tumors with variable amounts of papilla formation, mucin production, and cytoarchitectural atypia. Associated invasive carcinomas, reported to occur in up to 30% of patients, often are mucinous and clinically indolent. METHODS: The clinical and pathologic features of 28 IPMNs resected at Memorial Sloan-Kettering Cancer Center between 1983 and 1997 were reviewed. RESULTS: There were 16 females and 12 males with a mean age of 68 years (range, 44-79 years) and a mean tumor size of 4.5 cm (range, 1.5-11.0 cm). The head of the gland was the predominant tumor site (89%). Abdominal pain, weight loss, and acholic stool were the most common symptoms at presentation. According to histology, two types of papillae were identified: intestinal (22 patients) and pancreatobiliary (6 patients). In the intraductal component, cytologic atypia was minimal (i.e., intraductal papillary-mucinous [IPM] adenoma) in 2 patients and moderate (IPM borderline tumor) in 5 patients, and severe atypia (IPM carcinoma in situ) was seen at least focally in 21 patients. In addition, invasive carcinoma was identified in 15 patients (53%), 4 of whom had only microscopic foci. Invasive carcinoma was of the mucinous type (colloid) in six patients and of the tubular type (conventional ductal adenocarcinoma) in nine patients. At a median follow-up of 35 months, four patients died of disease; two of these patients had only borderline atypia with no identified in situ or invasive carcinoma in the sections submitted. Eighteen patients had no evidence of disease, 1 patient was alive with recurrent disease, and 5 patients died of other causes. The actuarial 5-year disease free survival rate was 78%. Of the 14 patients with invasive carcinoma, 5 of 6 patients with colloid type tumors were free of tumor at a mean of 55 months. Of the patients with tubular type invasive carcinoma, two patients died of their disease (at 4 years and 7 years), three patients died of other causes, and four patients were alive (three were free of disease, and one experienced disease recurrence) at an average follow-up of 7.5 years. CONCLUSIONS: Two distinct patterns of intraductal papillae are seen in patients with IPMNs: intestinal and pancreatobiliary. Both in situ and invasive carcinoma may be encountered more commonly than previously recognized. Tubular type invasive carcinomas occur as well as mucinous type (colloid) carcinomas. Although the neoplasms are less aggressive as a group than conventional pancreatic ductal adenocarcinoma, patients with IPMNs may pursue a deadly course, even in the absence of identifiable invasive carcinoma. Conversely, patients with tubular type invasive carcinoma arising in the background of IPMN may follow a more favorable course than patients with conventional ductal adenocarcinoma without IPMN, emphasizing the importance of recognizing the IPMN component in patients with pancreatic adenocarcinoma.