Endometrial Metaplastic/Reactive Changes Coexistent with Endometrial Hyperplasia and Carcinoma: A Morphological and Immunohistochemical Study

The aim of this study was to assess the relationship between endometrial metaplastic/reactive changes (EMRCs) and endometrial neoplastic lesions. Twenty cases of “simple” (without architecture complexity) EMRCs coexistent with endometrial malignant/premalignant lesions, twenty cases of neoplasia-unassociated EMRCs, and eight cases of complex metaplastic lesions were assessed by immunohistochemistry. EMRCs coexisted with endometrioid carcinoma (n = 12), atypical endometrial hyperplasia (n = 3), serous carcinoma (n = 2), and clear cell carcinoma (n = 3). Neoplasia-associated EMRCs showed a mean Ki67 labeling index of 12.6% (range 0–30%); with nuclear atypia in 16/20 (80%) cases; diffuse p16 expression in 15/20 (75%) cases; and heterogeneous ER, PR, and vimentin expression. Compared to the associated neoplasia, EMRCs showed a lower Ki67 expression (p < 0.001) and higher p16 expression (p < 0.001). No EMRC case showed mitotic activity, PTEN loss, MMR deficiency, nuclear β-catenin, p53-mutant pattern, Napsin A, or AMACR expression. No significant differences were found between neoplasia-associated and neoplasia-unassociated EMRCs. Complex metaplastic lesions showed a lower Ki67 expression than EMRCs (p = 0.044) and PTEN loss in 5/8 cases, even in the absence of nuclear atypia. In conclusion, neoplasia-associated simple EMRCs may show evident atypia and a worrisome immunophenotype, but no data support their involvement in endometrial carcinogenesis. Architectural complexity appears as a crucial factor to identify precancerous lesions.

Comparative Review of Malignant Melanoma and Histologically Well-Differentiated Melanocytic Neoplasm in the Oral Cavity of Dogs

Oral malignant melanoma (OMM) is the most common neoplasm of the canine oral cavity. It is characterized by its aggressive local disease as well as its high rate of lymphatic invasion and distant metastasis. OMM carries a poor prognosis, with most patients succumbing to the disease due to progression of the neoplasm. Histopathologically, OMM is characterized by significant nuclear atypia, a mitotic index of greater than 4/10 hpf, and evidence of vascular invasion or metastasis. Clinically, these lesions can become locally invasive, causing lysis of bones and severe inflammation of the surrounding soft tissue. With time, these lesions can spread to the regional lymph node and to the lungs and other organs. Prognosis can vary depending on the size of the primary tumor, regional node involvement, and distant metastatic disease; however, multiple studies report a relatively short median survival time ranging from less than 4 months to 8 months. Histologically well- differentiated melanocytic neoplasms (HWDMN) are a variant of OMM and sometimes referred to as canine oral melanocytic neoplasms of low malignant potential. Unlike OMM, patients with HWDMN have longer survival times. Histopathologically, HWDMNs have well-differentiated melanocytes with a low mitotic index of 3 or less per 10 hpf and minimal nuclear atypia. HWDMNs have better prognosis with a mean survival time of up to 34 months. This article is a comparative review of OMM and its less aggressive counterpart.

Prediction of non-muscle invasive bladder cancer recurrence using machine learning of quantitative nuclear features

Non-muscle invasive bladder cancer (NMIBC) generally has a good prognosis; however, recurrence after transurethral resection (TUR), the standard primary treatment, is a major problem. Clinical management after TUR has been based on risk classification using clinicopathological factors, but these classifications are not complete. In this study, we attempted to predict early recurrence of NMIBC based on machine learning of quantitative morphological features. In general, structural, cellular, and nuclear atypia are evaluated to determine cancer atypia. However, since it is difficult to accurately quantify structural atypia from TUR specimens, in this study, we used only nuclear atypia and analyzed it using feature extraction followed by classification using Support Vector Machine and Random Forest machine learning algorithms. For the analysis, 125 patients diagnosed with NMIBC were used; data from 95 patients were randomly selected for the training set, and data from 30 patients were randomly selected for the test set. The results showed that the support vector machine-based model predicted recurrence within 2 years after TUR with a probability of 90% and the random forest-based model with probability of 86.7%. In the future, the system can be used to objectively predict NMIBC recurrence after TUR.

Interpretive Errors in Fine-Needle Aspiration of Thyroid: A 13-Year Institutional Experience in Lebanon

<b><i>Introduction:</i></b> Fine-needle aspiration (FNA) is a worldwide established diagnostic tool for the assessment of patients with thyroid nodules. All thyroid FNA interpretive errors (IEs) were reviewed at the American University of Beirut Medical Center over a 13-year period, in order to identify and analyze them. <b><i>Materials and Methods:</i></b> All FNAs and their corresponding pathology results are correlated yearly for quality assurance. Discrepant cases are segregated into sampling errors and IEs. All thyroid FNAs with IEs were collected from 2005 to 2017. FNA and pathology slides were reviewed by trained, board-certified cytopathologists, adhering to the latest Bethesda criteria. Reasons for erroneous diagnoses were studied. <b><i>Results:</i></b> There was a total of 11 IEs out of 340 thyroid FNAs followed by surgical resection. Five benign follicular nodules (BFNs) were misinterpreted as suspicious for carcinoma. Focal nuclear atypia in cyst-lining or follicular cells and a monotonous population of macrophages misinterpreted as Hurthle cells (HCs) were the causes of IEs in this category. Four Hashimoto’s thyroiditis (HT) cases were misinterpreted as suspicious for malignancy. Innate atypia of HCs and sampling misinterpretation were the causes of IEs in HT. One medullary and 1 follicular carcinoma were misinterpreted as suspicious for follicular neoplasm and BFN, respectively. Nine cases were better classified after review. <b><i>Conclusion:</i></b> Thyroid FNA IEs can be mitigated by meticulous screening and identification of all elements on FNA smears. Awareness of focal nuclear atypia in reactive cyst-lining and follicular cells in BFN, as well as HCs in HT, is highlighted. Adherence to The Bethesda System for Reporting Thyroid Cytopathology and consulting experienced cytopathologists significantly decrease IEs.

Intraparenchymal Breast Leiomyoma and Atypical Leiomyoma

Introduction: Intraparenchymal breast leiomyoma is a rare lesion of breast. The diagnostic criteria to differentiate benign and borderline breast leiomyoma was not yet clear. No atypical leiomyoma of breast parenchyma has been reported. Case series presentation: We described one case of leiomyoma and one case of bilateral atypical leiomyoma in breast parenchyma. The morphological features that lead to the diagnosis of atypical leiomyoma include invasive growth pattern, mild nuclear atypia and mitotic figures up to 3mitoses/10HPF. Conclusion Due to the limited experience, cases presented as atypical intraparenchymal breast leiomyoma should be closely followed.

Malignant ossifying fibromyxoid tumor of the calvaria: illustrative case

BACKGROUND Ossifying fibromyxoid tumor (OFMT) is a rare entity of soft tissue tumor that most commonly occurs in the subcutaneous tissues of trunk or extremities with occasional cases involving the head and neck; however, primary involvement of the skull has not been reported. While historically considered slow-growing benign to intermediate malignant, few cases of atypical or malignant features have been described. OBSERVATIONS Herein, the authors present a case of malignant OFMT with primary skull and transcranial extension. The tumor caused lytic calvarial destruction with intra- and extracranial soft tissue components. Gross total resection was performed, and histopathology revealed malignant OFMT with 40 mitoses per 50 high-power fields and moderate nuclear atypia. LESSONS OFMT can rarely occur in the head and neck and, as reported herein, may involve the skull with intracranial extension. While no uniformly recognized histological criteria for malignancy exist, a three-tiered classification has been proposed: typical, atypical, and malignant, based on features such as hypercellularity, mitotic activity, infiltrative growth, and/or nuclear atypia. Malignant variants should be considered along the high-grade sarcoma spectrum with elevated risk for recurrence or metastatic spread. Routine adjuvant radiotherapy is not typically recommended; however, surveillance imaging is advised.

Primary peritoneal mucinous adenocarcinoma in a man

A 69-year-old man suffered from lethal peritoneal carcinomatosis. At autopsy, no primary lesion was identified in the gastrointestinal, pancreatobiliary, respiratory, urinary and male reproductive organs. The tumor consisted of mucin-containing and gland-forming columnar cells with minimal nuclear atypia. The final diagnosis was primary peritoneal mucinous adenocarcinoma in a man.