A 22-year-old man was admitted because of abdominal pain localized
to the right iliac fossa. An abdominal ultrasound scan was performed, which
revealed a 3.5 × 8-cm mass with heterogeneous content and
calcified walls in close proximity to the ascending colon. A computed
tomography (CT) scan of the abdomen showed a 10 × 3.5-cm
mass in the region of the appendix with homogeneous density, thin walls, and
some small areas of calcification ([Fig. 1]). A
colonoscopy was subsequently performed, which revealed a 5-cm mass protruding
from the appendiceal area with a central orifice and surrounding erythematous
mucosa ([Fig. 2]). A laparotomy and appendectomy
were performed, removing an 8 × 3.5-cm mass without
damaging the integrity of its surface. An exploration of the cecum showed that
it was not affected. Following histopathological analysis of the resected
tissue, the patient was diagnosed as having a simple or retention appendiceal
mucocele ([Fig. 3]).
Fig. 1 Computed tomography (CT)
image showing a 10 × 3.5-cm oval neoplasm with
well-demarcated, thin walls in the appendiceal region in contact with the
ascending colon.
Fig. 2 Colonoscopic view
showing a submucosal lesion protruding from the appendiceal area with the
typical “volcano sign” and erythematous mucosa.
Fig. 3 Histological appearance
of the appendectomy specimen showing pools of mucus, with low cellularity and
without atypia, that dissect the muscular layer, compatible with a retention
appendiceal mucocele.
The term “appendiceal mucocele” refers to obstruction
and dilatation of the appendiceal lumen due to accumulation of mucoid
substance; it can be a benign or malignant process. Appendiceal mucoceles can
be classified into four histopathological groups: simple or retention
mucoceles, mucosal hyperplasia
(5 % – 25 % of the total),
cystadenomas (63 % – 84 %), and
mucinous cystadenocarcinomas
(11 % – 20 %)
[1].
Mucoceles account for about
0.2 % – 0.3 % of appendectomies
[2]. Their clinical manifestations are usually
nonspecific; up to 50 % of cases are asymptomatic
[3]
. The typical endoscopic
appearance is of a submucosal lesion with bright mucosa protruding over the
appendiceal lumen, and sometimes the “volcano sign”, a central
orifice in the middle of the protruding mucosa, can be seen [4].
Appendiceal mucoceles smaller than 2 cm are rarely malignant;
those larger than 6 cm are usually considered malignant with a high risk
of rupture (20 %) [5]. In such cases,
surgical treatment is always indicated because of the high risk that the
mucocele will become malignant.
Endoscopy_UCTN_Code_CCL_1AD_2AJ
