Baylor University Medical Center Proceedings January 2014, Volume 27, Number 1 | Page 35

Mucocele of the appendix
Thomas H. Louis, MD, and Daniel F. Felter, MD

Mucocele of the appendix is a term used to describe a dilated, mucinfilled appendix. It is most commonly the result of epithelial proliferation,
but can be caused by inflammation or obstruction of the appendix.
Two cases of mucocele of the appendix are presented with a discussion of the histologic and radiologic features as well as the surgical
management.

CASE REPORTS
Case 1. A 30-year-old man presented to the emergency
department at Baylor University Medical Center at Dallas with
a 1-day history of cramping abdominal pain with nausea, vomiting, and diarrhea. He reported mild tenderness to palpation in
the left lower quadrant. The patient was afebrile with stable vital
signs and a normal white blood cell count. A contrast-enhanced
computed tomography (CT) study of the abdomen and pelvis
revealed the stomach, small bowel, and colon to be fluid filled.
These findings were compatible with the clinical impression of
gastroenteritis. The appendix was dilated to 1.6 cm and filled
with low-density material. Calcific deposits were present in the
wall of the appendix, but there were no surrounding inflammatory changes (Figure 1a). The CT findings were compatible with
a mucocele of the appendix, and a laparoscopic appendectomy
was performed. Final pathology revealed a mucinous cystadenoma of the appendix.
Case 2. A 72-year-old man presented to the emergency
department at Baylor University Medical Center at Dallas
with vomiting and acute worsening of longstanding abdominal pain with localization to the right lower quadrant. He
was in mild discomfort and had tenderness to palpation in
the right lower quadrant, greatest at McBurney’s point. The
patient had no peritoneal signs. A contrast-enhanced CT
study of the abdomen and pelvis showed the appendix to be
dilated to 2.7 cm and filled with low-density material. An
appendicolith was also present at the base of the appendix
(Figure 1b). The CT findings were compatible with a mucocele of the appendix, and a laparoscopic appendectomy
was performed. Histologic study of the excised appendix
revealed both chronic and acute inflammatory changes with
mucin accumulation and evidence of previously ruptured
appendiceal diverticulum.
Proc (Bayl Univ Med Cent) 2014;27(1):33–34

a

b

Figure 1. Mucocele of the appendix. (a) Coronal CT image of the right lower
quadrant in patient 1 shows a dilated appendix with thin calcification in the wall
(white arrow). (b) Axial CT image of the right lower quadrant in patient 2 shows
a dilated appendix with an appendicolith.

From the Department of Radiology, the University