Ileocolic intussusception caused by appendiceal mucocele

A 59-year-old woman presented to the emergency department with moderate abdominal pain in the right lower quadrant and hypogastrium for the past five days. The physical examination revealed tenderness in the right lower quadrant. Laboratory examination showed hyperleukocytosis (13000cells/m3) and increased CRP (27mg/L). Abdominal CT scan was performed for further evaluation.

An abdominal CT scan before and after intravenous contrast was performed, which shows an oval-shaped, thin-walled hypodense cystic lesion containing punctate and peripheral calcifications in the right lower quadrant (figure 1) invaginating in the cecum and the ascending colon (Fig. 2, Fig. 3). There are no signs of inflammation, ischemia, upstream bowel distension, abscess formation or peritoneal effusion. Based on these findings, the diagnosis of appendiceal mucocele complicated with ileocolic intussusception was made.

Pathological findings:

Histopathological examination confirmed the diagnosis of low-grade mucinous appendix neoplasm.

Appendiceal mucocele is defined as an intraluminal cystic dilatation of the appendix by the accumulation of mucinous material, which can affect either the whole organ or most often distally segment, it can be either benign or malignant[1,2].

Its presentation is rare and seen in about 0.2-0.3% of appendectomy specimens and about 8% of appendiceal tumours[3]. They typically occur during the sixth decade of life, although the age range is broad (50-70 years)[3]; more common in women and presenting as a palpable mass in the lower right quadrant of the abdomen with or without pain[3]. In some asymptomatic patients, mucoceles are found incidentally, when imaging is performed for other reasons or during the surgery. Pre-surgical radiological diagnosis through cross-sectional imaging is requisite and helps to determine surgical planning[3].

The final diagnosis of a benign or malignant tumour is confirmed through histopathology[3,4]. The treatment of choice is an appendectomy if there is suspicion of malignancy hemicolectomy should be performed to prevent dissemination of the disease, very careful mobilizing of the tumour is essential to avoid rupture of the mucocele[3,4].

Complications

Acute ileocolic intussusception.

Torsion or extrinsic compression on a neighbouring organ, particularly the ureter causing hydronephrosis. The most severe complication is a spontaneous or intraoperative rupture with the risk of tumour dissemination which may lead to pseudomyxoma peritonei associated with a high rate of mortality[3,4].