[Appendiceal mucoceles, pseudomyxoma peritonei and appendiceal mucinous neoplasms: update on the contribution of imaging to choice of surgical approach].

Introduction: The treatment of pseudomyxoma peritonei (PMPs) and appendiceal mucocele (AM) has changed radically. To assess the contribution of preoperative imaging to the treatment strategy and choice of approach, a surgeon and a radiologist different from the initial radiologist examined the files of all patients treated for PMP or AM in four facilities in one district from January 1, 1996, through December 31, 2008.

Patients And Methods: The study included 27 patients (20 men and seven women, mean age: 63+/-13 years). Eleven patients had an intact AM, seven synchronous PMP (malignant appendiceal lesion in two of seven), six metachronous PMP (five with peritoneal mucinous carcinomatosis and one with diffuse peritoneal adenomucinosis) and three a ruptured AM but not PMP. The incidence of mucin-secreting tumors observed (27 cases in 12 years in a region of 500 000 inhabitants) corresponds to a prevalence of approximately five cases per year per million inhabitants. Acute clinical pictures (7/27) were significantly more frequent for the malignant forms (5/7) (p<0,02).

Results And Discussion: The overall sensitivity of computed tomography (CT) for all the criteria studied was 93%. The predictive value for AM rupture of visualization of thick calcifications was 100%. On the other hand, rupture never occurred when the CT showed an AM under pressure, with thin walls and septa. The predictive value for PMP of "scalloping" was 100%. The diagnostic accuracy of the initial reading was 25/27 for the imaging overall and 25/25 for the CT. Preoperative visualization of the exact size of the intact AM or of diagnostic information about ruptured AM and PMP helped to select an appropriate approach in 25 of 27 cases.