Appendix برای بزرگنمایی عکسها کلیک را روی ان نگه دارید Figure 16.1 A, The layers of the walll of the appendix are similar to that of the large bowel. B, Irregular distribution of the crypts is a normal physiological variant and should not be misinterpreted as chronic idiopathic inflammatory bowel disease. C, Large lymphoid aggregates may disrupt the muscularis mucosae, and the overlying epithelium may be attenuated Figure 16.2 Lymphoid hyperplasia in children may be striking and is associated with viral infections as well as intussusception Figure 16.3 Paneth cells may be seen in the appendiceal mucosa (arrow), along with neuroendocrine cells Figure 16.4 Melanosis is common in both adults and children and is analogous to melanosis coli Figure 16.5 Fibrous obliteration of the appendiceal tip consists of a variable mixture of nerve fibers, fibrous tissue, Schwann cells, neuroen- docrine cells, and muscle Figure 16.6 A, The earliest gross findings in acute appendicitis consist of dullness of the serosal surface, with injection of the serosal vessels. B, As the inflammatory process progresses, there is variably present fibrinous or purulent exudates along with hyperemia or hemorrhage. C, Green, black, or purple discoloration of the appendiceal wall indicates gangrene. (Photographs courtesy of Dr. George F. Gray, Jr.) Figure 16.7 A, Early acute appendicitis with acute inflammation arising from a small mucosal defect. B and C, A more advanced case with massive acute inflammation extending into the muscular wall of the appendix, with extensive ulceration; residual mucosa is seen at the edges in B. D, Transmural inflammation and necrosis in gangrenous appendicitis Figure 16.8 Serosal vessels in cases of acute appendicitis are often packed with lymphocytes, mimicking chronic lymphocytic leukemia Figure 16.9 A, Interval appendectomy specimens often show lympho- histiocytic inflammation and transmural lymphoid aggregates that may mimic Crohn disease (B). (Courtesy of Dr. Joel K. Greenson.) Figure 16.10 A, Appendiceal diverticula, at the tip and along the side of an appendectomy specimen. B, The mucosa and submucosa herniate through the muscularis propria, similar to colonic diverticula. C, Ruptured appendiceal diverticula can mimic low-grade mucinous neoplasms; note the lack of neoplastic epithelium Figure 16.11 Mild architectural distortion and focal active inflammation in an appendix from a patient with ulcerative colitis Figure 16.12 Gross Specimen Showing Appendiceal Involvement by Crohn Disease. A, Note the marked wall thickening and extension of the inflammatory process into the periappendiceal fat. B, There is mural edema and transmural lymphoid aggregates; the overlying mucosa shows pyloric metaplasia. (Photographs courtesy of Dr. Henry Appelman.) Figure 16.13 A, Malakoplakia is composed of an infiltrate of macrophages that in this case destroys the normal appendiceal architecture. B, Michaelis-Gutmann bodies are characteristic (arrows) Figure 16.14 A, A resected appendix containing numerous pinworms. B, Typical appearance of pinworms within the appendiceal lumen, with eosinophilic cuticle and prominent lateral ala. C, Rarely, pinworms may invade the appendiceal mucosa. (A, Courtesy Dr. George F. Gray, Jr.) Figure 16.15 Larvae of Strongyloides stercoralis within the crypt epithelial cells of the appendix. (Courtesy Dr. Dennis Baroni-Cruz.) Figure 16.16 Appendiceal schistosomiasis featuring numerous calcified eggs with associated fibrosis within the wall of the appendix. (Courtesy Dr. Joseph Misdraji.) Figure 16.17 Yersinia infection of the appendix characteristically features epithelioid granulomas with prominent associated lymphoid tissue Figure 16.18 Actinomycosis of the appendix, featuring mucosal ulceration and mural fibrosis, with overlying clusters of bacteria with associated acute inflammation and Splendore-Hoeppli protein Figure 16.19 Appendix with pseudomembranes and dilated, "exploding" crypts typical of Clostridium difficile infection Figure 16.20 A, Typical "smudge cell" inclusions within the inflamed mucosa (arrows). B, Infected cells are highlighted by adenovirus immunostain Figure 16.21 Warthin-Finkeldey multinucleated giant cells in the appendix of a child with measles Figure 16.22 Innumerable CMV inclusions in the mucosa of an appendix. (Courtesy of Dr. Joseph Misdraji, MD.) Figure 16.23 H&E/methenamine silver stain highlights Histoplasma within macrophages in the appendiceal mucosa. The patient was immuno- compromised and died of disseminated histoplasmosis Figure 16.24 Hyperplastic polyp of the appendix, similar to hyperplastic polyps of the colon and rectum Figure 16.25 Gross Appearance of a Sessile Serrated Polyp/ Adenoma of the Appendix. A, There is a sessile polypoid lesions near the tip of the appendix that involves much of the mucosal surface. B and C, The crypts are elongated and dilated, with lateral branching or budding at the base, as well as reverse maturation. D, This sessile serrated polyp/adenoma contains a focus of conventional adenomatous dysplasia. The architecture reflects the background sessile serrated nature of the lesion. E and F, Some serrated polyps of the appendix contain abundant eosinophilic cytoplasm and pencillate nuclei, resembling traditional serrated adenomas of the left colon Figure 16.26 A, This tubular adenoma of the appendix is sharply demarcated from the surrounding mucosa and resembles a tubular adenoma of the colorectum. B, This large adenomatous polyp from the cecum extends to involve the appendiceal orifice and proximal appendix Figure 16.27 Nonmucinous adenocarcinoma of the appendix is histologi- cally similar to intestinal-type colorectal adenocarcinoma. This lesion arises in a background of adenomatous polyp and extends into the wall Figure 16.28 Primary signet ring cell carcinoma of the appendix Figure 16.29 A, Goblet cell carcinoids have a circumferential growth pattern and typically extend deeply into the muscle and mesoappendix. B, The small nests, clusters, and cords of neoplastic cells have large mucin vacuoles and small basally located nuclei. C, Paneth cells may be very prominent Figure 16.30 A and B, Poorly differentiated adenocarcinoma ex goblet cell carcinoid; note the nuclear atypia and infiltrating poorly differentiated glands admixed with elements of goblet cell carcinoid Figure 16.31 Ovarian metastasis of appendiceal adenocarcinoid tumor of goblet cell type. Sometimes this constitutes the initial presentation of this tumor type Figure 16.32 A, Mucinous cystadenoma involving the proximal half of the appendix and associated with formation of diverticula. Note the lack of mucin on the outside of the appendix. B, The epithelium is undulating with an intact muscularis mucosae and lacks architectural complexity. C, The cytologic atypia is low grade Figure 16.33 Adenoma confined to the appendix (A) but containing high-grade dysplasia (B), characterized by architectural complexity, nuclear atypia, and mitoses Figure 16.34 A, Low-grade appendiceal mucinous tumor featuring a markedly dilated appendiceal lumen and thin wall. B, Another case showing a markedly dilated appendix with extension of mucin into the mesoappendix (A, Courtesy of Dr. George F. Gray, Jr.) Figure 16.35 A, The epithelium of LAMNS is low grade, similar to cystadenomas, and is often flat or undulating. B, The epithelium is often denuded. C, LAMNS invade via a broad pushing front with effacement of the muscularis mucosae and mural atrophy, fibrosis, and/or calcification. D, Note the extremely thin wall separating mucin from mesoappendix in this case. E, This photograph shows mucin in the mesoappendix, with associated fibroinflammatory reaction and calcification Figure 16.36 A, Myxoglobulosis, or "caviar appendix," features numerous ovoid globules composed of mucus within the lumen. B, Histologically, the globules are composed of laminated mucin surrounding a granular eosinophilic core. (Photographs courtesy of Dr. Ian Brown.) Figure 16.37 A, Gross photograph from a debulking procedure for pseudomyxoma peritonei. B, In this case, strips of low-grade epithelium float within pools of mucin. C, This case of pseudomyxoma peritonei with high-grade features shows invasion of the fibrous bands surrounding the mucin pools, as well as signet ring cells and marked nuclear atypia (D). (A, Courtesy Dr. George F. Gray, Jr.) Figure 16.38 Gross Appearance of Well-Differentiated Neuroendo- crine Tumor (Formerly Carcinoid Tumor) of the Appendix. These tumors are white-yellow and characteristically located in the tip (A); they are well circumscribed but not encapsulated and may extend into the periappendiceal soft tissues (B). (Courtesy Dr. George F. Gray, Jr.) Figure 16.39 A, The majority of appendiceal NETs are composed of uncapsulated, tightly packed solid nests (insulae) of small monotonous cells with eosinophilic or amphophilic cytoplasm. B, Nuclei are uniform, small, and round, with speckled or "salt and pepper" chromatin. Lym- phovascular invasion is typical (arrow) Figure 16.40 A, L-cell NETs, formerly known as tubular carcinoids, are composed of trabeculae and cords of neoplastic cells that may be mistaken for a carcinoma. B, Small red acidophilic neuroendocrine granules may be present Figure 16.41 This well-differentiated NET has striking clear cytoplasm as well as eosinophilic neuroendocrine cells Figure 16.42 A and B, Endometriosis, characterized by endometrial glands and stroma, in the wall of the appendix. Endosalpingiosis in the outer wall of the appendix (C); cilia are visible at higher power (D). A focus of ectopic decidualization is seen on the left (E, arrow), while a focus of endometriosis is seen on the right Figure 16.43 A primary GIST arising in the wall of the appendix (A), confirmed by CD117 immunostaining (B) Figure 16.44 A, Metastatic squamous cell carcinoma from the cervix. B, Metastatic high-grade serous carcinoma from the ovary
