Neoplasms of the Appendix: Pictorial Review with Clinical and Pathologic Correlation

Abstract

Appendiceal neoplasms are uncommon tumors of the gastrointestinal tract that may manifest with symptoms of appendicitis, right lower quadrant pain, or palpable mass, leading to imaging or surgical intervention. The majority of appendiceal masses consist of primary epithelial neoplasms and neuroendocrine tumors (NETs). Epithelial neoplasms-mucinous and nonmucinous types-are more often detected at imaging than NETs due to their larger size and propensity for peritoneal spread and metastatic disease. Epithelial mucinous neoplasms are defined by the presence of mucin, detected at radiologic and pathologic examination. A mucocele or pseudomyxoma peritonei from epithelial mucinous tumors are the two most common cross-sectional imaging findings of appendiceal mucinous neoplasms. Nonmucinous epithelial tumors are less common and manifest as masses similar to colonic-type malignancies. NETs are often discovered incidentally at appendectomy due to their small size and nonaggressive behavior. Imaging findings of primary appendiceal tumors may overlap with those of acute appendicitis. Additionally, an appendiceal mass may cause acute appendicitis, obscuring the underlying mass. Other neoplasms including lymphoma, sarcoma, mesenchymal and nerve sheath tumors, or secondary malignant involvement of the appendix are rare. Treatment depends on the histologic subtype and extent of disease. Detailed description of organ, nodal, and peritoneal involvement informs surgical management with the goal of complete cytoreduction. Novel treatments such as hyperthermic intraperitoneal chemotherapy have increased survival for patients with mucinous tumors. RSNA, 2017.

Cistoadenocarcinoma of Appendix: Diagnosis and Treatmentat Emergency Room

“…Como es bien descrito, esta patología simula un cuadro de Apendicitis Aguda. Nuestro caso no es la excepción a dicha presentación clásica, puesto que incluso el diagnóstico preoperatorio fue el de una Peritonitis Aguda de probable etiología Apendicular (4,5,6) .…”

Spectrum of computed tomography manifestations of appendiceal neoplasms: acute appendicitis and beyond

“…1). (3) Often considered as a non-essential vestigial organ, the appendix is better known for its pathological role in acute appendicitis, one of the most common abdominal surgical emergencies. Acute appendicitis occurs when there is obstruction of the appendiceal lumen, leading to fluid accumulation, luminal distension and inflammation before finally resulting in perforation.…”

“…(1) Primary appendiceal neoplasms have a diverse histology comprising of epithelial tumours (mucinous and colonic subtypes), neuroendocrine tumours (NETs), goblet cell carcinoids, lymphoma, mesenchymal tumours and sarcomas. (3) NETs are the commonest, followed by epithelial neoplasms. In comparison, the other neoplasms are much rarer.…”

“…In comparison, the other neoplasms are much rarer. (1,3,5) The histology subtype and extent of disease at the time of diagnosis help to predict survival. For example, the presence of a signet-ring cell formation confers the worst prognosis with an average survival rate of six months, while a low-grade mucinous neoplasm gives a median overall survival of eight years.…”

“…NETs have little metastatic potential, occurring primarily in tumours greater than 2 cm in size and usually involving the regional lymph nodes. (1,3) Non-mucinous (colonic-type) epithelial tumours Non-mucinous epithelial tumours consist of adenomas, adenocarcinomas and polyps. These may obstruct the appendiceal lumen and often result in acute appendicitis (Fig.…”