Advances In Anatomic Pathology最新文献

World Health Organization cytopathology reporting system systems have proposed for the pancreatobiliary tract, lung, lymph node, and soft tissue aligned with the updates in the World Health Organization classification of Tumor series. Among them, the pancreatobiliary tract and lung specimen reporting system have been published recently and are now a 7-tier and 5-tier category system, respectively, without any subcategorization. World Health Organization reporting systems also encourage the application of ancillary diagnostic tests like cell block preparation, immunocytochemistry, and rapid on-site evaluation for better categorization of specimens and further management, especially in indeterminate (atypical and suspicious for malignancy) and malignant cytology categories. In this brief review, we aim to provide a brief outline of both the systems and their clinical risk-based management strategies.

Primary pericardial mesothelioma (PM) is a rare tumor arising from the mesothelial cells of the pericardium. It has an incidence of <0.05% and comprises <2% of all mesotheliomas; however, it is the most common primary malignancy of the pericardium. PM should be distinguished from secondary involvement by the spread of pleural mesothelioma or metastases, which are more common. Although data are controversial, the association between asbestos exposure and PM is less documented than that with other mesotheliomas. Late clinical presentation is common. Symptoms may be nonspecific but are usually related to pericardial constriction or cardiac tamponade, and diagnosis can be challenging usually requiring multiple imaging modalities. Echocardiography, computed tomography, and cardiac magnetic resonance demonstrate heterogeneously enhancing thickened pericardium, usually encasing the heart, with findings of constrictive physiology. Tissue sampling is essential for diagnosis. Histologically, similar to mesotheliomas elsewhere in the body, PM is classified as epithelioid, sarcomatoid, or biphasic, with the biphasic type being the most common. Combined with morphologic assessment, the use of immunohistochemistry and other ancillary studies is helpful for distinguishing mesotheliomas from benign proliferative processes and other neoplastic processes. The prognosis of PM is poor with about 22% 1-year survival. Unfortunately, the rarity of PM poses limitations for comprehensive and prospective studies to gain further insight into the pathobiology, diagnosis, and treatment of PM.

Mesotheliomas are rare and aggressive tumors that originate from mesothelial cells. Although exceedingly rare, these tumors may occur in children. Different from adult mesotheliomas, however, environmental exposures particularly to asbestos do not appear to play a major role in mesotheliomas in children, in whom specific genetic rearrangements driving these tumors have been identified in recent years. These molecular alterations may increasingly offer opportunities for targeted therapies in the future, which may provide better outcomes for these highly aggressive malignant neoplasms.

A remarkable amount of new information has been generated on peritoneal mesothelioma (PeM), ranging from nomenclature changes, including the removal of "malignant" when referring to this neoplasm and the use of the term "tumor" rather than "mesothelioma" to designate the neoplasm formerly known as "well-differentiated papillary mesothelioma", to the acknowledgment that PeMs can be associated with tumor predisposition syndromes or germline mutations. Although the disease is still more frequently seen in caucasian males, PeM is not uncommon in women. In addition, it can represent a diagnostic challenge when it has an uncommon presentation (ie, paraneoplastic syndrome or incidental finding) or when it has confounding histologic features. Ancillary testing, including immunohistochemical stains, in situ hybridization for CDKN2A or NF2 , and molecular studies, in selected cases, allows its correct diagnosis. The molecular landscape of PeM is still a work in progress; however, some findings, such as ALK gene rearrangements and EWSR1/FUS-ATF1 fusions, are specifically seen in PeM of young patients. The biological behavior of PeM is variable; however, cytoreductive surgery and hyperthermic intraperitoneal chemotherapy have markedly improved the survival of patients affected by this disease.

Pleural mesotheliomas represent one of the most common diagnostic challenges in thoracic pathology. The diagnosis of pleural mesothelioma weighs heavily on clinical and radiologic information. In addition, in the past, before the era of immunohistochemistry, the diagnosis was aided with the use of special histochemical stains-PAS, D-PAS, and mucicarmine, which now very much have been replaced by immunohistochemical stains. In the era of immunohistochemistry, a combination of carcinomatous epitopes and positive mesothelioma markers has become paramount in the diagnosis of mesothelioma, and more recently the use of molecular techniques has become another ancillary tool in supporting such a diagnosis. At the same time, the treatment and clinical outcome of these patients may in some measure be determined by the histopathological features of the tumor and one that also over the years has changed from a palliative type to surgery, chemotherapy, radiotherapy, or a combination of these types. The histopathological growth patterns of mesothelioma are also wide, and in some cases may mimic other tumors that may be primary or metastatic to the pleura. Therefore, the assessment of the diagnosis of mesothelioma is one that requires a global view of the different factors including clinical, radiologic, pathologic-including immunohistochemistry and molecular diagnosis.

Malignant mesothelioma is a rare tumor arising from the mesothelial cells that line the pleura, pericardium, peritoneum, and tunica vaginalis. Imaging plays a primary role in the diagnosis, staging, and management of malignant mesothelioma. Multimodality imaging, including radiography, computed tomography (CT), magnetic resonance imaging (MRI), and F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT), is used in a variety of scenarios, including diagnosis, guidance for tissue sampling, staging, and reassessment of disease after therapy. CT is the primary imaging modality used in staging. MRI has superior contrast resolution compared with CT and can add value in terms of determining surgical resectability in equivocal cases. MRI can further assess the degree of local invasion, particularly into the mediastinum, chest wall, and diaphragm, for malignant pleural and pericardial mesotheliomas. FDG PET/CT plays a role in the diagnosis and staging of malignant pleural mesothelioma (MPM) and has been shown to be more accurate than CT, MRI, and PET alone in the staging of malignant pleural mesothelioma. PET/CT can also be used to target lesions for biopsy and to assess prognosis, treatment response, and tumor recurrence.

Common well-differentiated hepatocellular lesions include focal nodular hyperplasia, focal nodular hyperplasia-like lesions, large regenerative nodule, hepatocellular adenoma, dysplastic nodule, and hepatocellular carcinoma. The term atypical hepatocellular neoplasm/hepatocellular neoplasm of uncertain malignant potential can be used especially in needle core biopsies when a well-differentiated hepatocellular lesion is either histologically atypical (focal reticulin loss, focal cytologic/architectural atypia) or is clinically atypical (male sex or female >50 y) and cannot be confidently classified as adenoma or hepatocellular carcinoma. These are resected in an attempt for more definite classification. Although radiology can suggest the diagnosis in some of the entities mentioned above, needle core biopsies are often performed to confirm the diagnosis and plan therapy. Diagnosis of these lesions on needle core biopsies can be challenging and may have overlapping histologic and sometimes even immunohistochemical features. Herein, we review the histologic, immunohistochemical, and molecular features of well-differentiated hepatocellular lesions, along with recent advances in this area. We also provide the best approach for the diagnosis of well-differentiated hepatocellular lesions with ancillary testing, especially on needle core biopsies, and discuss the pitfalls. Accurate recognition of well-differentiated hepatocellular lesions is essential as some of them have excellent prognosis and may not require resection, while others have histologic prognostic information that is key for management.

Genitourinary malignancies include a broad spectrum of distinct tumor entities occurring in the kidney, the urinary tract, the prostate, the adrenal glands, the penis, and testicles. Each tumor entity presents with unique biological characteristics, especially in terms of immunobiology. The immune landscape of genitourinary malignancies differs between immunoreactive tumors like urothelial carcinoma or carcinomas of the kidney, for which several immunotherapeutic treatment options have been approved in the past years. In contrast, prostate cancer presents with low immunogenicity and previous trials exploring immune checkpoint inhibitors and other immunotherapeutic agents did not proof substantial survival benefits. In this review, we are presenting a streamlined overview on the role of surgical pathologists within the contemporary practice of immune oncology. It includes current indications for pathologic programmed death-ligand 1 (PD-L1) assessment and important pathologic considerations on PD-L1 testing harmonization including interassay and algorithm variabilities. In addition, we will discuss emerging biomarkers beyond PD-L1 and their potential to predict immunotherapy responses including tumor mutational burden, microsatellite instability, gene expression signatures, and histologic factors.