Diagnostic Ultrasound - Abdomen and Pelvis

Appendiceal Mucocele
Diagnoses: Bowel
TERMINOLOGY
• Distension of appendiceal lumen as result of mucin
accumulation
IMAGING
• Distended tubular or pear-shaped cystic intraperitoneal
structure in right lower quadrant, traced from medial wall
of cecal pole
• Presence of calcification in wall strongly supports diagnosis
of appendicular mucocele
• Concentric layering of dense mucoid material gives onion
skin appearance on ultrasound
• Contrast-enhanced CT scan is best imaging tool
TOP DIFFERENTIAL DIAGNOSES
• Cystic ovarian neoplasm
• Hydrosalpinx
• Tubo-ovarian abscess
• Duplication cyst
KEY FACTS
• Appendiceal obstruction from appendiceal carcinoma
• Obstructive acute appendicitis
• Mesenteric cyst
PATHOLOGY
• Commonly caused by epithelial proliferation, which could
be benign or malignant
• Less commonly secondary to obstructive causes
CLINICAL ISSUES
• Most common presentation is right lower quadrant pain or
palpable mass
• Frequently discovered incidentally
• Pseudomyxoma peritonei (PMP): Serious complication of
spontaneous or iatrogenic rupture of appendicular
mucocele (benign or malignant)
• Preoperative differentiation of benign and malignant
mucoceles challenging
(Left) Longitudinal
transvaginal ultrasound shows
well-marginated, complex,
cystic mass containing dense
mucoid material giving onion
skin appearance. (Right)
Transvaginal axial ultrasound
image shows the central
echogenic inspissated mucoid
material .
(Left) Sagittal MPR image
from a CECT of the same
patient shows a tubular cystic
structure with the base ſt
attached to the cecal pole.
Note the central
homogeneous low
attenuation. (Right) T2 axial
image in the same patient
shows the cystic mass with
contents of uniform high
signal intensity. The base st
traced to the cecal pole.
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