The neoplastic appendix: a practical approach

Chronic intermittent abdominal pain in young woman with intestinal malrotation, Fitz-Hugh-Curtis Syndrome and appendiceal neuroendocrine tumor: a rare case report and literature review

“…The appendicular NETs are the most common appendicular tumor, mainly frequent in women (male-to-female ratio 1:2) of 40–50 years old [ 16 ]. Appendix is the third commonest site of the gastrointestinal tract (24 %) after small intestine (41.8 %) and rectum (27.4 %); they usually arise in the appendicular tip (70 %), morphologically similar to their small intestinal and rectal counterparts [ 17 ]. They may be asymptomatic by themselves and are usually incidentally found during appendectomy for presumed appendicitis, with the majority of cases < 1 cm in diameter (90 %); usually unspecific abdominal pain in the lower right abdomen leads to appendectomy, finding local inflammation and broadening of the appendix which may mimic the same macroscopic pattern of other appendicopathy, so therapeutic decision-making would not be altered [ 18 ].…”

“…In these cases, many pathological criteria should be considered, such as serosal or lymph vascular invasion, tumor margins, Ki67 index >2 % on immunohistochemistry and mitotic activity (more than 2 cells per mm2) [ 19 ]. As told, the prognosis is better than in other site, with distant metastasis in about 1 % of cases, always in NET >2 cm, and a 5-years survival rate greater than 95 % [ 17 ]. At first, the World Health Organization (WHO) classification provides a system for all NET, determining prognosis and treatment, including three main groups subdivided by organ of tumor origin: 1) well differentiated neuroendocrine tumors (benign behavior or uncertain malignant potential-“carcinoids”); 2) well differentiated neuroendocrine carcinomas (low-grade malignancy-“malignant carcinoids”); and 3) poorly differentiated carcinomas (high-grade malignancy) [ 19 ].…”

“…The appendicular NET are staged by both the AJCC Cancer Staging Manual, 7th edition and the International Union against Cancer (UICC) TNM classification 7th edition [ 20 , 21 ]; the WHO has harmonized them across gastrointestinal anatomic sites, a system largely in accordance with both the TNM and AJCC [ 22 ]. They can also be graded by assessing the mitotic activity or Ki-67 immunolabeling index; Grade 1 tumours (carcinoids) display <2 mitoses/10 high power fields or <2%Ki-67 index and Grade 2 tumours (“atypical carcinoids”) have mitotic counts of 2–20/10 high power fields or 3–20 % Ki-67 index [ 17 ]. Intestinal Malrotation is rarely diagnosed in adulthood.…”

The value of grading dysplasia in appendiceal mucinous neoplasm in the absence of pseudomyxoma peritonei

“…The remaining 41 cases were LAMN, characterised by villous or flat mucinous epithelium with low-grade dysplasia only. 3 Subepithelial fibrosis with complete obliteration of muscularis mucosae was seen in all cases. Of the LAMNs, 33 (80%) showed obliteration of muscularis propria, 23 (56%) had extraappendiceal mucin and eight (20%) cases had dysplastic epithelium with extra-appendiceal mucin.…”

“…greater than 80% of the lesion) high‐grade cytological or architectural dysplasia. The remaining 41 cases were LAMN, characterised by villous or flat mucinous epithelium with low‐grade dysplasia only . Subepithelial fibrosis with complete obliteration of muscularis mucosae was seen in all cases.…”