Case of the Month: July, 2011, Page 6

Answer: C. Tip

Key Points

  • Appendiceal neoplasms should be considered as a rare cause of focal appendiceal thickening.
  • The most common appendiceal neoplasm is carcinoid.
  • The appendix is the most common site in the gastrointestinal tract for carcinoid tumors to occur.
  • Most appendiceal carcinoids are located at the tip of the appendix, are less than 2 cm, and are benign.
  • Carcinoid syndrome in association with appendiceal carcinoid is rare.

Discussion

In this case, carcinoid tumor of the appendix presented with similar radiographic appearance to acute appendicitis. A CT scan showed thickening of the appendix, especially at the tip, and associated mesenteric stranding. Rarely, appendiceal pathology may be due to neoplasm such as carcinoid.

Carcinoid tumor of the appendix is usually discovered incidentally following appendectomy. This occurs with a frequency of 2 to over 10 cases per 1000 appendectomies, depending on the series. Most of these lesions occur at the tip of the appendix and may cause gangrenous perforation of the appendix. As in this case, this may lead to formation of periappendiceal abscess and appear similar to perforated appendicitis.

Carcinoid tumor of the appendix is the most common appendiceal neoplasm. Likewise, the appendix is the most common location for carcinoid tumor to occur within the gastrointestinal tract.

Carcinoid tumors of the appendix are usually benign. However, if the tumor is over 2 cm in diameter it is more likely to exhibit malignant behavior. Lesions less than 2 cm in diameter invade the appendiceal wall in 25% of cases but only 3% metastasize to lymph nodes. Hepatic metastases and the carcinoid syndrome are considered rare.

Appendectomy alone is adequate treatment unless the lymph nodes are visibly involved, the tumor is more than 2 cm in diameter, mucinous elements are present in the tumor (adenocarcinoid), or the mesoappendix or base of the cecum is invaded. Right hemicolectomy is recommended for these more aggressive lesions.

References

  • Parkes SE, Muir KR, Al Sheyyab M, et al. Carcinoid tumors of the appendix in children 1957-1986: incidence, treatment and outcome. Br J Surg 1993;80:502-504.
  • Doede T, Foss HD, Waldschmith J. Carcinoid tumors of the appendix in children: epidemiology, clinical aspects and procedure. Eur J Ped Surg 2000;10:372-377.
  • Dall'Igna, Patrizia; Ferrari, Andrea; Luzzatto, Claudia; Bisogno, Gianni; Casanova, Michela; Alaggio, Rita; Terenziani, Monica; Cecchetto, Giovanni. Carcinoid Tumor of the Appendix in Childhood: The Experience of Two Italian Institutions. Journal of Pediatric Gastroenterology & Nutrition: February 2005; Volume 40, Issue 2: 216-219.
  • Copron CA, Black T, Herzog CE, et al. A half century experience with carcinoid tumors in children. Am J Surg 1995;170:606-608.
  • Moertel CL, Weiland LH, Telander RL. Carcinoid tumor of the appendix in the first two decades of life. J Ped Surg 1990;25:1073-1075.
  • R. Price, R. Jeffrey, S. Vasanawala. Appendiceal hyperemia and/or distention is not always appendicitis: appendicitis mimicry in the pediatric population Clinical Imaging, Volume 33, Issue 5, Pages 402-405.

 

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