Current diagnostic pathology最新文献

Basal cell carcinoma (BCC) is the prototypical basaloid tumour of the skin, but may show various patterns simulating other cutaneous tumours, particularly squamous cell carcinoma and trichoepithelioma (TE). Other challenges are presented by BCC with marked pleomorphism, glandular differentiation, neuroendocrine differentiation, clear cells and sarcomatoid change. Peripheral palisading and retraction (artefact) of the epithelium from the stroma are the most useful features to support a diagnosis of BCC, but can occasionally be seen in other benign and malignant cutaneous neoplasms and are inconspicuous or lacking in some cases of BCC. Increased ‘stromal’ mucin accompanying retraction and peripheral palisading is extremely suggestive of BCC and is rarely seen in other tumour types. Diffuse and strong BerEP4 staining and absence of epithelial membrane antigen staining is characteristic of BCC, and is an immunophenotype rarely encountered in other tumours except for TE. CD10 staining of the basaloid epithelium, in the absence of significant stromal staining, may support a diagnosis of TE-like BCC rather than TE in more organized variants.

Sebaceous tumours include hyperplasia, adenoma, sebaceoma and carcinoma. Importantly, the latter three are potential markers of Torre–Muir syndrome, which is the hereditary association of sebaceous neoplasia and internal malignancy – most commonly colorectal carcinoma. The diagnostic features, differential diagnosis, molecular diagnostics and recent advances in our understanding of the pathogenesis of this rare group of tumours are discussed along with Torre–Muir syndrome and recommendations for screening for this important association.

The pathogenesis of intestinal metaplasia (IM) of the human stomach remains completely unknown. Several classifications of IM have been suggested. Recent investigators have examined epithelial cell phenotypes in IM through immunohistochemistry, and revealed that gastric IM glands consist of a mixture of gastric and intestinal cell phenotypes. This implies that a heterogeneous cell population with both gastric and intestinal phenotypes would develop into a single intestinal phenotype. Recently, an intestinal stem cell marker was found to be present in the putative position of human gastric glands, whereas it was absent in gastric IM glands. This supports the assumption that IM is a consequence of abnormal stem cell differentiation, leading to lack of differentiation into any of the normal intestinal epithelial phenotypes. Recent advances in molecular biology have revealed intestinal transcriptional factors (Cdx1/Cdx2), suggesting that upregulation of Cdx2 may trigger the initiation and development of IM in the stomach. Epidemiological evidence indicates that Helicobacter pylori is a major cause of IM but might not be solely responsible for its induction. A variation in host and bacterial background that predisposes to the development of IM has been revealed.

Alcohol is a substance that impacts the social, psychological, medical, economic and religious spheres of our existence. It is part of every society. Alcohol in moderation can be beneficial. Alcohol abuse mediates its effects both on the developing and the developed brain, directly or indirectly, and has acute and chronic complications. Damage to the developing brain can result from alcohol consumption in pregnancy. Misuse of alcohol in adults can affect both the central and the peripheral nervous system. Direct effects arise due to the toxic and intoxicating effects of alcohol. Nutritional deficiencies are thought to mediate most of the indirect effects of alcohol, as patients with alcohol dependence tend to eat less and derive most of their caloric intake from the alcoholic beverages they consume. Alcohol-related disease places a burden on our health-care systems. In this review, we examine the pathological effects of alcohol on the nervous system.

Gliomas are the commonest groups of tumours arising in the central nervous system (CNS) in both children and adults. Their incidence in both age groups appears to be increasing, for reasons that are poorly understood. The biological behaviour of gliomas varies from slow-growing well-demarcated tumours that are curable by excision to malignant invasive tumours that are uniformly fatal. Pathology has a major role to play in the management of patients with gliomas by providing a histological diagnosis and tumour grade, which are of major prognostic significance. Molecular genetic studies have found loss of genetic material in many gliomas, with progressive losses identified with increasing tumour grade. In oligodendrogliomas, loss of heterozygosity on chromosomes 1p and 19q is of therapeutic significance as a predictor of tumour response to chemotherapy. The forthcoming revision of the WHO classification of CNS tumours is expected to provide updated recommendations on glioma diagnosis and grading.

Demyelination is characterised by destruction of normal myelin and can be either primary or secondary. Multiple sclerosis is the most common primary demyelinating disease. The disease commonly affects females with a mean age of onset of about 30 years. It is characterised clinically by relapses and remissions of neurological disturbance. The aetiology is multifactorial with gender, genetic and environmental factors contributing to disease susceptibility. The diagnosis remains clinical and confirmation is by histological examination of tissue obtained from multiple sites within the nervous system. Grossly, the brain shows numerous plaques scattered throughout the white and grey matter. The basic lesion on histology is the ‘demyelinated plaque’ with preserved axons set in a gliotic matrix. However, various other lesion types and patterns of demyelination are also identified histologically. Current research is investigating the role of stem cells and oligodendrocyte progenitors, and their potential in the repair of surviving axons.

Gestational trophoblastic neoplasia refers to the spectrum of conditions characterised by proliferation of conceptus-derived trophoblast, and includes partial and complete hydatidiform mole (HM), invasive mole, choriocarcinoma and placental site trophoblastic tumour and its variants. With changes in the management of early pregnancy complications in recent years, the majority of HMs are now evacuated in the late first trimester, at which time, it is now recognised, their histopathological features, although characteristic, may differ from those traditionally described following second-trimester evacuation. In view of these changes in presentation, updated histopathological criteria are presented and specific additional issues discussed, including recent advances in molecular genetics, ancillary investigations, recurrence risk, development of persistent trophoblastic neoplasia, intraplacental choriocarcinoma and mole with coexisting fetus.

Neoadjuvant therapy is increasingly used in the treatment of gastrointestinal malignancies. New molecular target-specific agents also have a role in downstaging hepatic colorectal metastases and metastatic gastrointestinal stromal tumours. Pathologists need to be familiar with post-treatment changes and with tumour regression grading systems. Accurate assessment of specimens is crucial for prognostic purposes and to evaluate therapeutic response. A standardized pathological approach is recommended.

Antenatal magnetic resonance imaging (MRI) has become a widely available technique for examining the fetus during its normal development and in a variety of diseases, prompting the question of whether it should supplant the traditional incisional route to diagnosis. We review and compare the applications and limitations of both MRI and classical neuropathology, illustrated with selected cases. We conclude that fetal MRI should be regarded as neither threat nor irrelevance, but complimentary to neuropathological practice. For many conditions, combined information from the two investigations can support a diagnosis that would be tentative with either alone.