Dual carcinoid/epithelial neoplasia of the appendix

We report a series of 13 lesions of the human vermiform appendix in which a carcinoid component was associated with a separate non-carcinoid epithelial component that included an adenoma-like lesion of the mucosal epithelium. We use the term dual carcinoid/epithelial neoplasia to describe this phenomenon. The carcinoid component was insular/trabecular in nine cases, tubular in one case and of goblet cell type in three. The epithelial component was a mucinous cystadenoma in four, a mucinous tumour of uncertain malignant potential in three, and a mucinous cystadenocarcinoma in six. No intermediate cell population was seen and in three cases the carcinoid and epithelial components were in different parts of the appendix, leading us to suggest that these lesions may be true 'collision' tumours in which two neoplasms have arisen in the same organ. The prognosis appears to be no worse than for either of the components alone, but conclusions regarding these lesions must be guarded on account of their rarity and the small numbers available for study.     

Synchronous adenocarcinoma of the transverse colon,the gallbladder and the vermiform appendix

Summary According to the literature synchronous adenocarcinomas of both, the colon and the gallbladder or the colon and the appendix are extremly unusual. To our knowledge the simultaneous occurrence of all three tumors has never been published before. Preoperative diagnosis of early stage tumors of the gallbladder and the vermiform appendix is also made very seldom.The following case report records an instance of synchronous adenocarcinomas of the gallbladder, the transverse colon, in a colonic polyp and the appendix. Owing to the patient's advanced age simultane cancer occurrence may be mere coincidence. Nevertheless, this extremely rare entity could also be ascribed to a genetic defect or an unknown carcinogenic agent.     

Malignant pleural effusions due to adeno-endocrine-cell carcinoma of the appendix: A case report

The cellular features of adeno-endocrine-cell carcinoma of appendiceal origin are presented. The pleural fluid contained metastatic predominantly atypical cells in linear cluster accompanied by numerous mesothelial cells. The cells had small round nuclei, with a slight tendency to molding; nucleoli were absent. The cytologic findings in Papanicolaou-stained smears of the pleural fluid suggested a metastatic small-cell carcinoma of the lung. Subsequently, adeno-endocrine-cell carcinoma of the appendix was demonstrated at autopsy. Reports of such occurrences are few; no study, to the best of our knowledge, has previously documented the cytologic diagnosis in pleural fluid. Diagn. Cytopathol. 16:522–525, 1997. © 1997 Wiley-Liss, Inc.     

Benign hepatocellular lesions and neoplasms: a comprehensive review

The prevalence of benign mass-forming liver lesions has significantly increased in recent years due to advances in diagnostic imaging. In general, these lesions can be either neoplastic or nonneoplastic and carry a different prognosis and management. Among benign mass-forming lesions of the liver, hemangiomas are the most common, followed by focal nodular hyperplasia, which is encountered ten times more frequently than adenomas. Hepatocellular adenomas are the third most common benign tumor of the liver. Their classification was revised in 2016 based on histomorphology and molecular signatures and includes hepatocyte nuclear factor-1 alpha (HNF1A)-mutated hepatocellular adenomas, beta-catenin 1 (CTNNB1) gene–mutated hepatocellular adenomas, interleukin-6 signal transducer gene–mutated or inflammatory/telangiectatic hepatocellular adenomas, and unclassified hepatocellular adenomas. Since then, a new subtype has been discovered, decreasing the proportion of unclassified cases. Hepatocellular adenomas have different molecular characteristics, behavior, and management, depending on the subtype. The telangiectatic subtype tends to bleed and may cause hemoperitoneum whereas the beta-catenin mutated subtype can progress to malignancy and is surgically resected independent of the size or symptoms. Other hepatic lesions include nodular regenerative hyperplasia, which occurs in the setting of blood flow alterations; and focal fatty change or benign steatotic nodules. Lastly, epithelioid angiomyolipomas are very uncommon benign mesenchymal liver tumors that belong to a family of tumor arising from perivascular epithelioid cells (PEComas) either sporadically or in the setting of tuberous sclerosis. Herein, we review these benign hepatic lesions and neoplasms and discuss the histomorphology and immunohistochemistry that allow us to render a specific diagnosis.     

Diagnostic challenge of secondary (metastatic) ovarian tumors simulating primary endometrioid and mucinous neoplasms

Secondary (metastatic) neoplasms to the ovary often cause diagnostic problems, especially those tumors that produce large, symptomatic ovarian tumors that masquerade clinically and pathologically as primary ovarian tumors of surface epithelial type. Most of these tumors arise from organs of the digestive system. Except for typical Krukenberg tumors, which usually originate in the stomach and generally are easily recognized, the most diagnostically problematic secondary ovarian tumors are those that originate in the large intestine, appendix, and pancreas. Metastases from these sites typically produce histologic patterns resembling primary ovarian endometrioid carcinoma or mucinous epithelial neoplasms of borderline and malignant types. This review focuses on the diagnostic challenge of distinguishing these secondary ovarian tumors from primary ovarian neoplasms. Studies on useful or potentially applicable immunohistochemical stains are also detailed.     

Variations and morphometric features of the vermiform appendix: A systematic review and meta-analysis of 114,080 subjects with clinical implications

Determining the true and indisputable data regarding the vermiform appendix (VA) morphology is of a great clinical interest. The aim of this study was to provide the best evidence-based anatomical overview of the variations in location and size of VA using a systematic and meta-analytical approach. A systematic review with meta-analysis was performed of studies reporting variants of the location and morphometric data regarding the VA. The MEDLINE/PubMed, ScienceDirect, EMBASE, BIOSIS, SciELO, and Web of Science databases were thoroughly searched throughout June 2018. The reported locations of the body of the VA were re-classified into a new, standardized classification system divided into nine categories. The AQUA tool was used to assess the quality of included studies. The research was conducted following PRISMA guidelines and registered at PROPSERO database. Our meta-analysis included 242 studies (n = 114,080). Overall, the VA was most commonly found in the retrocecal location (32.1%, 95%CI: 29.2–35.1), followed by the pelvic (28.5%, 95%CI: 26.7–30.4) and ileal (14.5%, 95%CI: 11.8–17.7) locations. Subjects without known appendiceal pathologies had significantly smaller VA outer diameters (5.84 mm, 95%CI: 5.68–5.99) than patients diagnosed with acute appendicitis (10.64 mm, 95%CI: 10.14–11.15). The overall pooled mean length of the VA was 80.29 mm (95%CI: 76.68–83.89). Significant differences were found in size of the VA between imaging modalities. The results obtained from this evidence-based anatomy study will improve the clinical understanding of the VA anatomy, which in turn will have major implications for clinical practice. Clin. Anat. 32:85–98, 2019. © 2019 Wiley Periodicals, Inc.     

Reproducibility of a histogenetic classification of thymic epithelial tumours

A histogenetic classification of thymic epithelial neoplasms proposed by Müller-Hermelink and co-workers has been shown by a number of recent studies to be of clinical and prognostic value. Reproducibility is an important criterion for the acceptance of any new classification for general diagnostic use. The reproducibility of this classification was tested on 51 cases of thymic epithelial neoplasia, by comparing results obtained by pathologists working from published criteria only with those results obtained by the pathologists who developed the classification. In 78% of cases there was complete concordance of results. Analysis of the 22% discordant cases showed that this discordance was due to a degree of subjectivity in determining cut-off points between categories adjacent to each other in the morphological spectrum of thymic epithelial neoplasia (medullary v. mixed, cortical v. well-differentiated thymic carcinoma). In terms of the important clinical distinction between benign (medullary and mixed) thymomas and those with more aggressive biological behaviour (cortical types and well-differentiated thymic carcinoma), the degree of reproducibility was 96%. The high degree of reproducibility of this histogenetic classification of thymic epithelial neoplasms should facilitate its acceptance and use in routine diagnostic pathology.     

Intussusception of the appendix: A report of three cases with different clinical and pathologic features

Three cases of intussusception of the appendix (IA) with distinctive pathologic changes were reported. All patients were women with different clinical presentations. Grossly, a complete intussusception was found in one case (case 1), while the others (cases 2 and 3) showed a partial intussusception. In case 1, almost the total segment of the appendix bearing the villous adenoma with focal malignant transformation became completely telescoped into the cecum. In case 2, no underlying appendiceal lesion was disclosed. In case 3, appendiceal endometriosis was found as the point of traction. Awareness of such a rare complication associated with various appendiceal lesions provides a clue for making an accurate diagnosis and selecting appropriate surgical management.     

Melanosis of the appendix: prevalence, distribution and review of the pathogenesis of 47 cases

The appendix is reported to be a common site for melanosis, especially at autopsy although to date there have been few studies expanding or qualifying this statement. Based on 47 cases identified from a series of 636 consecutive surgical specimens the prevalence, pattern of distribution, nature of the pigment and current knowledge of the aetiology and pathogenesis of melanosis of the appendix is reviewed and compared with melanosis coli.     

Isolation and culture of colonic epithelial cells in serum-free medium

Summary Techniques are described for the dissociation, fractionation through Percoll, and in vitro maintenance of mucosal epithelia from the human or guinea pig large bowel. Tissue recovered after surgery is predigested with trypsin-citrate and treated subsequently with a mixture of trypsin, citrate, and collagenase. The resulting suspension of single cells, cell clusters, and partially digested crypts is suspended over a Percoll solution and enriched in multicellular elements by two sequential centrifugations. The recovered multicellular complexes are inoculated to specially treated culture vessels in a serum-free medium supplemented with epidermal growth factor, insulin, transferrin, selenium, and bovine pituitary extract. Epithelia, characterized as such by transmission electron microscopy, adhere to the substrate, form colonies, and can be maintained routinely for study for at least 10 wk.     

Cytology of solid and papillary epithelial neoplasms of the pancreas: a case report

A case of rare pancreatic tumor in a 39-yr-old woman is reported. Fine-needle aspiration biopsy was performed; frozen sections later allowed definite diagnosis. Cytologic features of the tumor are described, and histogenesis is discussed.     

Primary epithelial neoplasms and other epithelial lesions of the appendix (excluding carcinoid tumors)

Epithelial tumors of the appendix range from low-grade mucosal-based tumors which, when confined to the appendix, have an excellent prognosis but, once outside the appendix, have a fair prognosis and often a prolonged disease course, to high grade invasive carcinomas that are rapidly fatal. Low grade mucinous neoplasms may rupture and spread to the peritoneum as pseudomyxoma peritonei, and the nomenclature of these tumors has been the subject of considerable disagreement among pathologists; the designation "low grade appendiceal mucinous neoplasm" has recently been proposed for reasons discussed herein. Demonstrating rupture of these neoplasms may require particularly diligent gross and microscopic evaluation as the rupture site often heals over leaving only subtle evidence of its presence. Invasive adenocarcinomas are often mucinous and may also spread to the peritoneum. Against this backdrop, the clinical and pathologic features of low grade appendiceal mucinous neoplasms and mucinous adenocarcinomas, as well as other types such as typical colorectal type and signet-ring cell type, are reviewed. In addition, emerging entities, serrated polyps and serrated adenomas, whose significance is only beginning to be understood, are considered. Retention cysts, hyperplastic polyps, and diffuse mucosal hyperplasia, although not necessarily neoplastic, are reviewed here as they may enter into the differential diagnosis of appendiceal mucinous neoplasms.     

Cytokeratin 14 expression in epithelial neoplasms: a survey of 435 cases with emphasis on its value in differentiating squamous cell carcinomas from other epithelial tumours

AIMS: The tissue distribution of cytokeratin 14 (CK14) in epithelial neoplasms is not well defined. We have evaluated 435 cases of epithelial neoplasm of various origins with cytokeratin 14 monoclonal antibody with special attention to possible use in differential diagnosis. METHODS AND RESULTS: Immunohistochemistry (ABC-HRP method) was performed for detection of CK14. We found that the expression of cytokeratin 14 was generally restricted to: (i) the majority of cases of squamous cell carcinoma regardless of origin (67/74) and degree of differentiation; (ii) neoplasms with focal squamous differentiation, including endometrial, and ovarian adenocarcinoma, malignant mesothelioma and transitional cell carcinoma; (iii) thymoma (8/8); (iv) myoepithelial components of salivary gland pleomorphic adenoma (3/4); and (v) oncocytic neoplasms, including thyroid Hurthle cell adenoma (1/1) and salivary gland Warthin's tumour (2/2). CONCLUSION: CK14 protein is a useful marker in differential diagnosis of squamous cell carcinomas.     

Modes of Helicobacter colonization and gastric epithelial damage

A total of 144 gastric biopsies colonized by Helicobacter-like organisms were studied under light and differential interference contrast microscopy for the modes of bacterial colonization. Biopsies were also graded for the degree of epithelial damage (epithelial-damage-grade: 0 to 6, in ascending order of severity) and density of Helicobacter-like organism (Helicobacter-grade: 0 to 6, in ascending order of bacterial density). Three modes of colonization were identified: free-in-mucus, surface-adhesion and intercellular colonization. Because light microscopy cannot definitely prove the presence of intracellular colonization, bacteria located between cells and below the apical cell border were counted together as intercellular colonization. Bacteria free-in-mucus were seen in all biopsies. Surface adhesion was seen in 50-87.9% of biopsies, without obvious correlation with the epithelial-damage- and Helicobacter-grades. The incidences of intercellular and intracellular colonization were directly proportional to the epithelial-damage- and Helicobacter-grades. Free-in-mucus as the predominant mode of colonization was mainly seen in biopsies with lower (1-3) epithelial-damage- and Helicobacter-grades. Conversely, biopsies with intercellular colonization as the predominant mode of colonization were mainly cases with higher (4-6) epithelial-damage- and Helicobacter-grades. In cases showing predominantly bacteria between cells, 69.2% had a gastric ulcer whereas only 38.8% of cases showing predominantly bacteria free-in-mucus showed ulceration (P < 0.01). These results indicate that Helicobacter-like organisms can invade and penetrate between epithelial cells. When free-in-mucus, Helicobacter-like organisms are less likely to induce epithelial damage. However, the more invasive modes of colonization (intercellular) were associated with severe epithelial damage and high Helicobacter density.(ABSTRACT TRUNCATED AT 250 WORDS)     

Benign tumors and tumor-like lesions of the adult kidney. Part I: Benign renal epithelial neoplasms

The spectrum of renal neoplasms has expanded in recent years. Although most of the work taking place in this field has concerned malignant neoplasms of the kidney, there have been significant improvements in our knowledge of benign renal tumors and tumor-like lesions, especially in renal cell adenoma, renal oncocytoma, and renal angiomyolipoma. Awareness and knowledge of these benign lesions is important because they are often included in the differential diagnoses of malignant tumors, with which they may be confused both clinically and pathologically. The authors review the topic of benign renal neoplasms and tumor-like lesions that occur in adults, emphasizing some of the newly described aspects of these lesions.     

肾损伤因子-1在肾上皮性肿瘤中的表达及临床意义

目的 明细胞癌、乳头状肾细胞癌、肾嫌色细胞癌、Xp11.2易位/TFE3基因融合相关性肾癌和转移性透明细胞癌中的表达率分别是77.8%(49/63)、90.9%(20/22)、1/13、7/7和87.5%(21/24),7例嗜酸细胞腺瘤均阴性.在原发性肾透明细胞癌中,KIM-1弥漫阳性表达更易发生于Furhman细胞核Ⅲ/Ⅳ级的病例(P=0.010).肾特异性钙黏蛋白主要表达于嫌色细胞癌和嗜酸细胞腺瘤.结论 KIM-1仅表达于损伤的近曲小管和由其起源的肿瘤,对原发性和转移性肾透明细胞癌、乳头状肾细胞癌及Xp11.2易位/TFE3基因融合相关性肾癌具有高度的特异性和敏感性,与肾特异性钙黏蛋白合用可以提高原发性肾脏上皮性肿瘤组织学分类的准确性和转移性肾透明细胞癌的诊断率.     

The histopathological classification,diagnosis and differential diagnosis of mucinous appendiceal neoplasms,appendiceal adenocarcinomas and pseudomyxoma peritonei

The vermiform appendix is the primary site of several distinctive benign and malignant neoplasms. Some can produce the clinical syndrome of pseudomyxoma peritonei (PMP). A consensus on their terminology was reached by an international panel of pathologists and clinicians working under the auspices of the Peritoneal Surface Oncology Group International (PSOGI), and this review discusses the application of the PSOGI classification to routine reporting. We discuss diagnosis and differential diagnosis together with implications for patient management, covering low‐grade appendiceal mucinous neoplasms, high‐grade appendiceal mucinous neoplasms, serrated polyps, adenomas and adenocarcinomas. We do not cover goblet cell tumours or neuroendocrine neoplasms in this paper.     

Clear cell carcinoid of the appendix: Report of two cases with literature review

The clear cell/lipid‐rich change has been described in neuroendocine tumors in several organs, but rarely observed in the appendix. In this study, we describe the morphologic, immunohistochemical features of incidentally discovered appendiceal carcinoids entirely represented by clear cells in a 22‐year‐old man and a 52‐year‐old woman. Ultrastructual examination demonstrated abundant lipid droplets and dense core granules. The mechanism leading to lipid accumulation in the cytoplasm has not been discovered, but degenerative processes following recurrent inflammatory change might be considered. This uncommon variant of appendiceal classic carcinoid tumors may bear a superficial resemblance to goblet carcinoid and/or appendiceal metastases from clear cell carcinoma. Awareness of clear cell carcinoid of the appendix will prevent incorrect diagnosis and unnecessary aggressive management.