Endocrine Pathology最新文献

Although pediatric thyroid tumors have many similarities to those occurring in adults, significant differences are also recognized. For example, although thyroid nodules in children are much less common than in adults, a higher percentage is malignant. Moreover, while pediatric papillary thyroid carcinoma (PTC) is associated with more advanced disease, death due to disease in children and adolescents is very rare, even when distant metastases are present. Some subtypes of thyroid carcinoma, like diffuse sclerosing variant, are especially common in children and adolescents. Moreover, certain histologic findings, such as a tall cell morphology or increased mitotic activity, may not carry the same prognostic significance in children as in adults. Recent studies exploring the molecular underpinnings of pediatric thyroid carcinoma indicate that while driver alterations of thyroid tumorigenesis in children and adults are essentially the same, they occur at very different frequencies, with translocation-associated tumors (most commonly harboring RET and NTRK fusions) comprising a sizable and distinct group of pediatric PTC. DICER1 mutations, an infrequent mutation in adult thyroid tumors, are relatively frequent in pediatric encapsulated follicular-patterned thyroid tumors (with or without invasion or nuclear features of PTC). Additionally, tumor predisposition syndromes (most notably DICER1 syndrome and PTEN hamartoma tumor syndromes such as Cowden syndrome) should be considered in children with thyroid tumors, especially follicular-patterned thyroid tumors and poorly differentiated thyroid carcinoma. This review will explore the current state of knowledge of thyroid nodules and carcinomas in children and adolescents.

Mucoepidermoid carcinoma (MEC) and sclerosing MEC with eosinophilia (SMECE) are rare primary thyroid carcinomas. In this study, we aimed to present our multicenter series of MEC and SMECE and integrated our data with published literature to further investigate the clinicopathological characteristics and prognoses of these tumors. We found 2 MECs and 4 SMECEs in our multicenter archives. We performed fluorescence in situ hybridization (FISH) to determine the MAML2 gene rearrangement. We screened for mutations in BRAF, TERT promoter, and RAS mutations using Sanger sequencing and digital polymerase chain reaction. Histopathologically, MECs and SMECEs were composed of two main cell types including epidermoid and mucin-secreting cells, arranged in cords, nests, and tubules. SMECEs were characterized by a densely sclerotic stroma with abundant eosinophils. We did not detect any MAML2 fusion in any of our cases. Two MEC cases harbored concomitant BRAF p.V600E and TERT C228T mutations. RAS mutations were absent in all cases. Concurrent foci of another thyroid malignancy were more commonly seen in MECs (p < 0.001), whereas SMECEs were associated with chronic lymphocytic thyroiditis (p < 0.001). MECs and SMECEs had equivalent recurrence-free survival (RFS) but MECs conferred significantly dismal disease-specific survival (DSS) as compared to SMECEs (p = 0.007). In conclusion, MECs and SMECEs not only shared some similarities but also demonstrated differences in clinicopathological characteristics, prognoses, and molecular profiles. SMECEs had a superior DSS in comparison to MECs, suggesting that they are low-grade cancers. This could help clinicians better evaluate patient outcomes and decide appropriate treatment plans.

Pheochromocytoma and abdominal paraganglioma (PPGL) are rare neuroendocrine tumors originating from chromaffin cells. Even though only 10-15% of the tumors metastasize, all PPGLs are considered potentially malignant. Topoisomerase 2A (TOP2A) is a protein involved in cell proliferation and has been found to be over-expressed in metastatic PPGL. To provide support whether TOP2A could serve as a prognostic marker, 88 PPGLs (of which 8 metastatic/relapsing) and 10 normal adrenal gland samples were assessed for TOP2A mRNA expression using quantitative real-time PCR (qRT-PCR) and TOP2A immunohistochemistry. Comparisons to clinical parameters connected to metastatic behavior were made, and The Cancer Genome Atlas was used for validation of the results. A significant association between high TOP2A mRNA expression in primary PPGL and subsequent metastatic events (p = 0.008) was found, as well as to specific histological features and clinical parameters connected to metastatic behavior and mutations in SDHB. TOP2A immunoreactivity was calculated as an index of positive nuclei divided by the total amount of nuclei, and this index associated with TOP2A mRNA levels (p = 0.023) as well as the Ki-67 labeling index (p = 0.001). To conclude, TOP2A is a potential prognostic marker as it is frequently elevated in PPGL displaying subsequent metastatic disease, and future studies in larger cohorts are warranted to determine if a TOP2A index as assessed by immunohistochemistry could be a marker of poor outcome. Additionally, elevated levels of TOP2A could indicate a potential actionable event, and future studies with topoisomerase inhibitors would be of interest.

Medullary thyroid carcinoma (MTC) is a C-cell-derived epithelial neuroendocrine neoplasm. With the exception of rare examples, most are well-differentiated epithelial neuroendocrine neoplasms (also known as neuroendocrine tumors in the taxonomy of the International Agency for Research on Cancer [IARC] of the World Health Organization [WHO]). This review provides an overview and recent evidence-based data on the molecular genetics, disease risk stratification based on clinicopathologic variables including molecular profiling and histopathologic variables, and targeted molecular therapies in patients with advanced MTC. While MTC is not the only neuroendocrine neoplasm in the thyroid gland, other neuroendocrine neoplasms in the thyroid include intrathyroidal thymic neuroendocrine neoplasms, intrathyroidal parathyroid neoplasms, and primary thyroid paragangliomas as well as metastatic neuroendocrine neoplasms. Therefore, the first responsibility of a pathologist is to distinguish MTC from other mimics using appropriate biomarkers. The second responsibility includes meticulous assessment of the status of angioinvasion (defined as tumor cells invading through a vessel wall and forming tumor-fibrin complexes, or intravascular tumor cells admixed with fibrin/thrombus), tumor necrosis, proliferative rate (mitotic count and Ki67 labeling index), and tumor grade (low- or high-grade) along with the tumor stage and the resection margins. Given the morphologic and proliferative heterogeneity in these neoplasms, an exhaustive sampling is strongly recommended. Routine molecular testing for pathogenic germline RET variants is typically performed in all patients with a diagnosis of MTC; however, multifocal C-cell hyperplasia in association with at least a single focus of MTC and/or multifocal C-cell neoplasia are morphological harbingers of germline RET alterations. It is of interest to assess the status of pathogenic molecular alterations involving genes other than RET like the MET variants in MTC families with no pathogenic germline RET variants. Furthermore, the status of somatic RET alterations should be determined in all advanced/progressive or metastatic diseases, especially when selective RET inhibitor therapy (e.g., selpercatinib or pralsetinib) is considered. While the role of routine SSTR2/5 immunohistochemistry remains to be further clarified, evidence suggests that patients with somatostatin receptor (SSTR)-avid metastatic disease may also benefit from the option of ¹⁷⁷Lu-DOTATATE peptide radionuclide receptor therapy. Finally, the authors of this review make a call to support the nomenclature change of MTC to C-cell neuroendocrine neoplasm to align this entity with the IARC/WHO taxonomy since MTCs represent epithelial neuroendocrine neoplasms of endoderm-derived C-cells.

The effects of many pharmacological agents on thyroid function are well known. Direct influences on measurements of thyroid function tests are also described. However, certain classes of drugs produce morphological changes in the gland. This review focuses on the significance of the following drug classes for the thyroid pathologist: iodine, antithyroid drugs, psychotropic drugs, antibiotics, cardiotropic drugs, antidiabetic drugs, and immunomodulatory agents. Radioactive iodine initially induces mild histologic changes; however, the long-term effects include marked follicular atrophy, fibrosis, and nuclear atypia-changes that vary depending on the pre-therapy condition of the gland. Some psychotropic drugs have been associated with a spectrum of inflammatory changes throughout the gland. The tetracycline class of antibiotics, namely minocycline, can lead to a grossly black thyroid gland with pigment seen in both colloid and follicular epithelial cells while variably present within thyroid nodules. The surgical pathologist most commonly sees an amiodarone-affected gland removed for hyperthyroidism, and the histologic findings again depend on the pre-therapy condition of the gland. While GLP-1 receptor agonists carry an FDA black box warning for patients with a personal or family history of multiple endocrine neoplasia or medullary thyroid carcinoma, the C cell hyperplasia originally noted in rats has not borne out in human studies. Finally, thyroiditis and hypothyroidism are well known complications of checkpoint inhibitor therapy, and rare cases of severe thyroiditis requiring urgent thyroidectomy have been reported with unique histologic findings. In this review, we describe the histologic findings for these drugs and more, in many cases including their functional consequences.

This review outlines how the alterations in the 5th edition of the WHO Classification of Endocrine and Neuroendocrine Tumors of the thyroid gland are likely to impact thyroid cytopathology. It is important to note that WHO subclassifies thyroid tumors into several new categories based on increased comprehension of the cell of origin, pathologic features (including cytopathology), molecular classification, and biological behavior. The 3rd edition of the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) will debut in the near future and will include changes in diagnostic category designations. The changes in the 5th edition of the WHO will in some instances subtly, and in other instances significantly, impact the cytological diagnoses. Moreover, these changes will also affect other thyroid FNA classification schemes used internationally for classifying thyroid FNA specimens.

Papillary thyroid carcinomas (PTCs) are driven by a variety of molecular abnormalities including BRAF, RAS, ALK, RET, and NTRK alterations. PTCs driven by the BRAFV600E mutation, or tumours which demonstrate a similar gene expression profile to PTCs driven by this mutation, have been reported to demonstrate specific morphological features sometimes termed "BRAFV600E-like" atypia. BRAFV600E-like atypia is characterised by a well-developed papillary architecture, infiltrative growth, marked nuclear clearing, prominent intranuclear pseudoinclusions, abundant eosinophilic cytoplasm, and scattered psammoma bodies. We sought to investigate the sensitivity and specificity of these morphological features for the presence of BRAFV600E mutation in PTCs as determined by mutation specific immunohistochemistry. An unselected cohort of 495 PTCs was reviewed by a single pathologist and categorised into three groups: typical BRAFV600E-like atypia (145 cases, 29%), possible BRAFV600E-like atypia (166 cases, 33%) and little/no BRAFV600E-like atypia (184 cases, 37%). The specificity and sensitivity of typical BRAFV600E-like atypia for the BRAFV600E mutation was 97.2% and 44.3%, respectively. When typical and possible BRAFV600E-like atypia were analysed together, the specificity was 70.6% and the sensitivity was 81.7%. In the morphologically little/no BRAFV600E-like atypia group, 58 cases (31.5%) had a BRAFV600E mutation. We conclude that typical BRAFV600E-like atypia is highly specific for the presence of the BRAFV600E mutation; however, the absence of BRAFV600E-like atypia does not exclude this mutation.

Poorly differentiated thyroid carcinoma (PDTC) and high-grade differentiated thyroid carcinoma (HGDTC) are considered high-grade follicular-derived thyroid carcinomas, with prognoses intermediate between well-differentiated and anaplastic thyroid carcinoma. Both share the presence of invasion, thyroid follicular-cell origin, and tumor necrosis or increased mitoses (≥ 3 mitoses per 2 mm² in PDTC and ≥ 5 mitoses per 2 mm² in HGDTC), without anaplastic dedifferentiation. PDTC must possess solid, trabecular, or insular growth and lack classic papillary-like nuclei; HGDTC can be of any architectural or nuclear morphology (follicular-like, papillary-like, oncocytic). Transformation may be accompanied by acquisition of high-risk mutations (such as TP53 or TERT promoter) on top of RAS-like or BRAF p.V600E-like (including NTRK-fusion) initial driver mutations. These carcinomas most frequently affect adults and often present with metastases (20-50%) or wide local invasion. As PDTC and HGDTC may be radioactive iodine resistant, post-surgical therapy may consist of external beam radiotherapy or targeted, mutation-dependent chemotherapy, such as tyrosine kinase inhibitors. Ten-year disease specific survival is as low as 50%. Awareness of high-grade features in the diagnostic setting is important for patient prognosis and triage of tissue for molecular analysis in order to guide relevant clinical management and therapy.

The incidence of well-differentiated non-functioning pancreatic neuroendocrine tumors (NF-PanNET) increased during the last decades. The risk of relapse after curative surgery, albeit low, is not negligible; moreover, adjuvant treatment is currently not an option and a reliable predictive model based on prognostic characteristics is urgently needed for tailoring a follow-up strategy. The histological classification of PanNET now relies only on the proliferative activity (mitosis and Ki67) and staging. In contrast to other endocrine neoplasms, the role of infiltrative growth pattern in NF-PanNET is not taken into consideration at present. In the current study, 247 consecutive patients who underwent surgical resection for a NF-PanNET were examined for the histological growth pattern of the tumor. Two distinct patterns (non-infiltrative vs. infiltrative) were described with the latter being further subclassified according to the type of structures invaded by the tumor (non-infiltrative: pattern 1; infiltration of adjacent pancreatic parenchyma and/or peripancreatic soft tissue: pattern 2; invasion of nearby organs and/or major vessels: pattern 3). The infiltrative growth resulted to be strongly associated with a poorer survival compared to a non-infiltrative growth (p < 0.001). In particular, the distinction between pancreatic parenchyma and/or peripancreatic soft tissue invasion versus adjacent organs and/or major vessels invasion was the most powerful predictor of recurrence after surgery at multivariate analysis (pattern 2 vs. pattern 1: HR 10.136, p = 0.028; pattern 3 vs. pattern 1: HR 15.775, p = 0.015). The infiltrative growth pattern could therefore provide additional prognostic information implementing the current grading and staging system.