Utility of non-contrast-enhanced magnetic resonance imaging in predicting preoperative clinical stage and prognosis in patients with thymic epithelial tumor

PURPOSE

The purpose of this study was to find useful imaging features on non-contrast-enhanced magnetic resonance imaging (MRI) that can divide patients with thymic epithelial tumor (TET) into clinical stage I-II and III-IV groups under assumption that contrast media are contraindicated.

MATERIALS AND METHODS

This retrospective study included 106 patients (median age, 60 years; range, 27-82 years; 62 women) with surgically resected TET who underwent MRI between August 1986 and July 2015. All cases were classified according to the 2015 WHO classification and staged using the eighth edition of the TNM system. Two radiologists independently evaluated 14 categories of MRI findings; the findings in patients with stage I-II were compared with those of patients with stage III-IV using a logistic regression model. Disease-specific survival associated with significant findings was calculated using the Kaplan-Meier method.

RESULTS

Univariate analysis showed that stage III-IV patients were more likely to have tumors with an irregular contour, heterogeneity on T1WI, low-signal intensity on T2WI, irregular border with lung, findings of great vessel invasion (GVI) (hereafter, GVI sign), pericardial thickening/nodule, and lymphadenopathy (all, P < 0.01). On multivariable analysis, only two findings, irregular border between tumor and lung (odds ratio [OR], 272.8; 95% CI 26.6-2794.1; P < 0.001) and positive GVI sign (OR, 49.3; 95% CI 4.5-539.8; P = 0.001) remained statistically significant. Patients with one or both features had significantly worse survival (log-rank test, P < 0.001).

CONCLUSION

For patients with TET who are unable to receive contrast for preoperative staging, the two image findings of an irregular border between tumor and lung and the positive GVI sign on non-contrast-enhanced MRI could be helpful in determining stage III-IV disease which is associated with a worse survival.

Immunohistochemistry in the diagnosis and classification of neuroendocrine neoplasms: what can brown do for you?

This review is based on a presentation given at the Hans Popper Hepatopathology Society companion meeting at the 2019 United States and Canadian Academy of Pathology Annual Meeting. It presents updates on the diagnosis and classification of neuroendocrine neoplasms, with an emphasis on the role of immunohistochemistry. Neuroendocrine neoplasms often present in liver biopsies as metastases of occult origin. Specific topics covered include 1. general features of neuroendocrine neoplasms, 2. general neuroendocrine marker immunohistochemistry, with discussion of the emerging marker INSM1, 3. non-small cell carcinoma with (occult) neuroendocrine differentiation, 4. the WHO Classification of neuroendocrine neoplasms, with discussion of the 2019 classification of gastroenteropancreatic neoplasms, 5. use of Ki-67 immunohistochemistry, 6. immunohistochemistry to assign site of origin in neuroendocrine metastasis of occult origin, 7. immunohistochemistry to distinguish well-differentiated neuroendocrine tumor G3 from poorly differentiated neuroendocrine carcinoma, 8. lesions frequently misdiagnosed as well-differentiated neuroendocrine tumor, and 9. required and recommended data elements for biopsies and resections with associated immunohistochemical stains. Next-generation immunohistochemistry, including lineage-restricted transcription factors (e.g., CDX2, islet 1, OTP, SATB2) and protein correlates of molecular genetic events (e.g., p53, Rb), is indispensable for the accurate diagnosis and classification of these neoplasms.

Relevance of calcification and contrast enhancement pattern for molecular diagnosis and survival prediction of gliomas based on the 2016 World Health Organization Classification

OBJECTIVES

The significance of conventional neuroimaging features for predicting molecular diagnosis and patient survival based on the updated World Health Organization (WHO) classification remains uncertain. We assessed the relevance of neuroimaging features (ring enhancement [RE], non-ring enhancement [non-RE], overall gadolinium enhancement [GdE], and intratumoral calcification [IC]) for molecular diagnosis and survival in glioma patients.

PATIENTS AND METHODS

We evaluated 234 glioma patients according to the updated WHO classification. Isocitrate dehydrogenase (IDH), H3F3A, BRAF hotspot mutations, TERT promotor mutation, and chromosome 1p/19q co-deletion were examined. RE, non-RE, GdE, and IC were evaluated as significant neuroimaging findings. Kaplan-Meier analyses were performed to evaluate overall survival (OS) and the correlations of prognostic factors were evaluated by log-rank tests. Univariate and multivariate analyses were performed to detect prognostic factors for OS.

RESULTS

A total of 207 patients were eligible. In 110 patients presenting RE, 102 (93%) were glioblastoma (GBM), IDH-wild type. In 97 patients without RE, presence of GdE or IC were not significantly different between IDH-mutant and -wild type tumors, whereas presence of GdE was a significant indicator of higher WHO grades. IC was the only significant finding for 1p/19q co-deleted tumors. TERT promoter mutation was observed in 7/17 patients with diffuse astrocytic glioma, IDH-wild type; recently-defined as "molecular GBM." IC, RE, and GdE were observed with lower prevalence in molecular GBMs. While presence of RE, GdE, and absence of IC were significant factors of OS in overall cohort, presence of GdE was not significant in OS in cases without RE, and IDH-mutant tumors. IC was a significant predictor of favorable OS in cases without RE and IDH-wild type tumors. Multivariate analysis also validated these findings.

CONCLUSION

GdE alone is not a significant predictor of IDH mutation status, but the pattern of enhancement is a significant predictor with RE demonstrating high sensitivity and specificity for GBM, IDH-wild type. Predicting "molecular GBM" by conventional neuroimaging is difficult. Moreover, GdE is not a significant factor of survival analyzed with pattern of enhancement or molecular stratifications. IC is an important radiographic finding for predicting molecular diagnosis and survival in glioma patients.

The World Health Organization classification of odontogenic and maxillofacial bone tumors: An appraisal

Classification is the process of grouping similar entities under one category for the ease of their comprehension and better handling. Medical classification dates back to the days of William Farr who is credited with the development of a nosology, which later served as the forerunner for the modern-day disease classification by ICD. The WHO system of classification is a time-honoured system that has prevailed from decades together and is under constant evolution. The classification of odontogenic tumours was first formulated by Pierre Paul Broca and has undergone several transformations over years. Though the earlier classifications and their modifications by several authors and even by the WHO appeared to be fitting for their time, the latest edition of WHO classification of odontogenic and maxillofacial bone tumours neither seems to be complete nor perfect, even at the present context. It is unfortunate that even with the advancement of molecular biology, the present WHO classification on Odontogenic and Maxillofacial bone tumours, fails to serve as a 'reference standard' in the true sense of the term. This article highlights the limitations of the current classification with constructive criticism that may help in further improvement.