Goblet cell adenocarcinoma(GCA)of the appendix is a rare neoplasm with histological features of both neuroendocrine tumors and adenocarcinomas. Compared to classical carcinoid tumors, GCA reveal a higher frequency of lymph node metastasis and generally have a poorer prognosis. Here, we report 2 cases of appendiceal GCA. The first case involved a 70-year- old woman who underwent elective appendectomy following management for acute perforated appendicitis. Pathology revealed a GCA with subserosal invasion(pT3), prompting additional laparoscopic ileocecal resection with D3 lymphadenectomy. The postoperative course was uneventful, and no residual tumor or nodal metastasis was observed(pStage Ⅱa). No recurrence was noted at 1-year follow-up. The second case involved a 46-year-old man with terminal ileal stenosis identified on computed tomography during an evaluation for nausea and vomiting. Colonoscopy revealed a narrowed and inflamed ileal segment;however, biopsy was non-diagnostic. Surgery was indicated after failure of conservative management. Intraoperatively, peritoneal nodules suggestive of dissemination and a tumor mass in the ileocecal region were observed. Laparoscopic ileocecal resection was conducted to preserve adjacent structures. Pathology confirmed GCA (pT4bN2aM1c1, pStage Ⅳc). The patient is currently undergoing systemic chemotherapy with CAPOX and bevacizumab. Although treatment often follows colorectal cancer protocols, no standardized regimen has been established, and further case accumulation is needed.

Well-differentiated neuroendocrine tumors are the most common neoplasm of the appendix. They are graded and staged using World Health Organization and American Joint Committee on Cancer criteria, respectively. They may be invisible grossly or form rounded yellow nodules, sometimes in the appendiceal tip. They show classic neuroendocrine tumor features microscopically, forming nests and cords of monotonous cells with salt-and-pepper chromatin and amphophilic cytoplasm. They are positive for neuroendocrine markers by immunohistochemistry, but their molecular characteristics are not well defined. pT-category staging relies primarily on tumor size, though higher-stage cases may involve the subserosa or mesoappendix. Few entities enter the differential diagnosis, but lesions such as goblet cell adenocarcinoma, poorly differentiated neuroendocrine carcinoma, and mixed neuroendocrine-non-neuroendocrine neoplasm may be considered. Appendiceal neuroendocrine tumors may metastasize to regional lymph nodes, but farther spread is rare. The most consistently proven risk factor for such spread is tumor size, though different studies have proposed different cutoffs. Other potential risk factors include lymphovascular invasion and margin positivity. Tumors smaller than 1 cm can be treated by appendectomy, while hemicolectomy is recommended for tumors larger than 2 cm. Proper treatment for cases measuring 1-2 cm remains a matter of debate.

Well-differentiated neuroendocrine tumors (NET) are rare malignancies that are clinically very heterogeneous. Accordingly, their treatment is also complex and dependent on various factors. With currently available systemic therapies, the prognosis is often favorable. This article aims to provide an overview of current treatment strategies for NET, addressing the most important NET locations. The current European guidelines and further relevant literature on the treatment of NET were reviewed for this purpose. The therapeutic spectrum for NET is extremely broad: For NET of the stomach/duodenum, appendix, and rectum, endoscopic or surgical resection is often sufficient, and metastatic tumors are rare. NET of the pancreas, small intestine and lung should also undergo potentially curative resection in the early stages. In the metastatic stage, locoregional treatments such as surgery and liver tumor embolization play a role. Major advances have been made in drug therapy, with somatostatin analogs (octreotide and lanreotide), an mTOR inhibitor (everolimus), and a tyrosine kinase inhibitor (sunitinib) being widely used. Peptide receptor radionuclide therapy (PRRT) is also an invaluable option. In some cases, classic chemotherapy is indicated. Many effective therapies are now available for NET. It is important to select the right therapy at the right time for each patient through interdisciplinary management. HINTERGRUND: Gut differenzierte neuroendokrine Tumoren (NET) sind seltene Malignome, die klinisch sehr heterogen sind. Entsprechend ist auch ihre Behandlung komplex und von diversen Faktoren abhängig. Mit den heute verfügbaren Therapien ist die Prognose oft günstig. Dieser Artikel soll einen Überblick über die aktuellen Therapiestrategien bei NET geben und dabei auf die wichtigsten NET-Lokalisationen eingehen. Zu diesem Zweck wurden die aktuellen europäischen Leitlinien und die einschlägige Literatur zur Behandlung von NET zusammengefasst. Das Therapiespektrum ist ausgesprochen breit: Bei den NET des Magens/Duodenums, der Appendix und des Rektums ist oft die endoskopische respektive chirurgische Entfernung ausreichend, und metastasierte Tumoren sind selten. NET des Pankreas, des Dünndarms und der Lunge sollen in frühen Stadien auch einer potenziell kurativen Resektion zugeführt werden. Im metastasierten Stadium haben lokale Therapiemaßnahmen wie Chirurgie und Leber-Tumorembolisation ebenfalls einen Stellenwert. Zuletzt gab es viele Fortschritte hinsichtlich der medikamentösen Therapie, wobei insbesondere Somatostatin-Analoga (Octreotid und Lanreotid), ein mTOR-Inhibitor (Everolimus) und ein Tyrosinkinase-Inhibitor (Sunitinib) eingesetzt werden. Ferner stellt die Peptidrezeptor-Radionuklid-Therapie (PRRT) ein wichtiges Verfahren dar. Auch die klassische Chemotherapie ist in einigen Fällen indiziert. Inzwischen gibt es viele effektive Therapien für NET. Es ist wichtig, im interdisziplinären Management für jeden Patienten und jede Patientin die richtige Therapie zum richtigen Zeitpunkt auszuwählen. Diseases of the appendix present in two varieties: infectious/inflammatory and neoplastic etiologies. The latter can present in the form of epithelial, neuroendocrine tumors (NETs), lymphoma, mesenchymal tumors, sarcomas, and metastases. Most neoplastic causes are epithelial tumors and NETs, with the former occurring in middle-aged or older adults and the latter occurring in younger patients. Though neoplastic processes of the appendix are typically asymptomatic, they can grow to cause obstruction, eventually resulting in symptoms of acute appendicitis. They can also produce vague pain symptoms in the right lower quadrant (RLQ) or a palpable mass. In severe cases, especially with mucinous neoplasms, they can cause pseudomyxoma peritoneii, which characteristically presents as mucin in the peritoneum and serosa of abdominal or pelvic organs. Acute appendicitis is a prevalent cause of abdominal pain, with an estimated lifetime risk of 7 to 9%. It classically presents with periumbilical pain that localizes to the right lower quadrant and nausea, vomiting, anorexia, and fever. The right lower quadrant pain is typically located half the distance between the umbilicus and anterior superior iliac spine (ASIS), known as McBurney’s point. Acute appendicitis may result from an obstructing fecalith or another typically mechanical obstruction. A feared complication of acute appendicitis is perforation, with a risk of 2% at 36 hours, increasing by 5% every 12 hours. With worsening inflammation, patients can develop more intense tenderness to palpation and guarding. Given the complications of acute appendicitis, an early, accurate diagnosis is crucial.

Appendiceal neurendocrine tumours (NETs) are rare neoplasms and diagnosis is commonly incidental following appendectomy. We aimed to review our experience with appendiceal NETs. Records of children with appendiceal NETs were reviewed and data concerning demographic characteristics, clinical findings, surgical procedures, histopathological findings, management and outcomes were recorded. Between 1985 and 2021, 33 cases with appendiceal NETs (median age 11.8 years, range 7.8-16; male/female = 10/23) were identified. All but one patients presented with abdominal pain, six had vomiting, four had fever and they underwent appendectomies with presumed diagnosis of acute appendicitis. Abscess drainage and appendectomy was performed in a 16-year-old girl for suspected right ovarian mass, and tumour was positive in the omentum. Histopathological diagnosis was classical carcinoid tumour (NET) in all cases. Median tumour size was 0.9 cm (n = 26, range, 0.1-3.5 cm); tumours were ≤1 cm in 19 cases, 2 cm in one, 3.5 cm in another case. Tumours were located in the tip (n = 11), body (n = 6) and base of appendix (n = 1) (in others data unavailable). In 28 patients with data, tumour extended to submucosa in five, to tunica muscularis in seven, to subserosa in six, to serosa in six, to mesoappendix in three, to periappendiceal fat in one. Three cases were lost to follow-up, 31 cases were alive (median follow-up 53 months). Paediatric appendiceal NETs do not behave aggressively and appendectomy alone is sufficient for tumours ≤2 cm regardless of local invasion. The need for further extensive surgery in tumours >2 cm also remains controversial.

Goblet cell adenocarcinoma and signet-ring cell adenocarcinoma are well-known diagnostic pitfalls of routine appendectomy specimens. Here we present a case of acute appendicitis with prominent neuronal (ganglion cell) hyperplasia and swelling which histologically mimics goblet cell adenocarcinoma and signet-ring cell adenocarcinoma. Attention to the cytologic features of the lesional cells (absence of atypia, mitotic activity) and their close association with nerves and classic ganglion cells, along with the use of a limited panel of immunostains, ensures proper classification of this rare but striking benign process.