Diagnostic Ultrasound - Abdomen and Pelvis

Extraovarian Adnexal Mass
1036
Differential Diagnoses: Female Pelvis
DIFFERENTIAL DIAGNOSIS
Common
• Subserosal Leiomyoma/Broad Ligament Fibroid
• Hydrosalpinx/Hematosalpinx/Pyosalpinx
• Peritoneal Inclusion Cyst
• Paraovarian/Peritubal Cyst
• Endometrioma
• Ectopic Pregnancy
Less Common
• Gastrointestinal
○ Bowel Loop
○ Appendicitis
○ Appendicular Mucocele
○ Gastrointestinal Stromal Tumor (GIST)
• Lymphatics
○ Lymphocele
○ Lymph Nodes
• Vascular
○ Hematoma
○ Aneurysm
○ Pelvic Varices
• Urinary Tract
○ Bladder Diverticulum
○ Pelvic Kidney
• Neurogenic
○ Perineural/Arachnoid Cyst
○ Neurofibroma
Rare but Important
• Tubal Torsion
• Müllerian Duct Anomaly
• Malignant
○ Malignant Transformation of Endometrioma
○ Tubal Carcinoma
• Risk of Malignancy
○ Tail Gut Cyst
• Mimics of Malignancy
○ Endosalpingiosis
○ Actinomycosis
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
• Is the mass ovarian or extraovarian?
○ Ovarian origin can be confirmed by relationship to
gonadal vessels and round ligament
○ Identifying separate ipsilateral ovary confirms
extraovarian origin
○ In larger ovarian lesions, splayed ovarian stroma and
ovarian blood supply confirm ovarian origin
• Is the mass intra- or extraperitoneal?
○ Relationship to iliac vessels will help to establish
extraperitoneal location
○ Extraperitoneal lesions have flattened interfaces with
pelvic wall
• Is the mass gynecological or non-gynecological?
○ Establishing uterine or tubal origin narrows differential
diagnosis
• Is there a typical clinical history?
○ Pregnancy status and features of sepsis are crucial
diagnostic clues
• Transvaginal ultrasound is superior to transabdominal for
demonstrating these features
○ See separate movement of mass from ovary with "slide
test"
• MR is excellent where ultrasound is inconclusive
Helpful Clues for Common Diagnoses
• Subserosal Leiomyoma/Broad Ligament Fibroid
○ Oval or round extraovarian mass
○ Multiple refractory and acoustic shadows due to fibrous
and calcific components
○ Demonstrable attachment to uterus with serpiginous
feeding vessels
○ Acute pain and inflammation suggests torsion
○ Broad ligament fibroids have similar characteristics but
no uterine feeding vessels
• Hydrosalpinx/Pyosalpinx
○ Coexist with pelvic inflammatory disease (PID),
endometriosis, adhesions
○ C- or S-shaped interconnecting tubular cystic structures
○ Incomplete internal septations represent folds
○ Internal echoes suggests hematosalpinx or pyosalpinx
○ Real-time ultrasound essential to demonstrates tubular
morphology
○ Wall thickening and complexity suggest pyosalpinx
– Often bilateral and may contain gas
– Clinical features of sepsis and cervical motion
tenderness
• Peritoneal Inclusion Cyst
○ Develop in presence of functioning ovary
○ History of pelvic inflammation, endometriosis or surgery
○ Fluid-filled cavity engulfing ovary
○ Ovary may be suspended by adhesions (spider web sign)
or eccentrically placed within fluid
○ Conform to pelvic contours
• Paraovarian/Peritubal Cysts
○ Thin-walled, unilocular anechoic cyst
○ Ipsilateral ovary demonstrated separately
○ Usually < 2 cm in diameter
○ If multiple, consider endosalpingiosis
• Endometrioma
○ Homogeneous low-level internal echoes represent
hemorrhagic debris
○ Demonstrate acoustic enhancement
○ Multilocularity and hyperechoic wall deposits can be
present
○ Often located in pelvic cul-de-sac
○ Associated with adenomyosis and solid fibrotic
endometriosis
○ May coexist with tubal distension or inclusion cysts
• Ectopic Pregnancy
○ Tubal ring sign; extrauterine hypoechoic cystic structure
with concentric hyperechoic wall
○ Extrauterine live pregnancy pathognomonic but seen in
minority
○ Uterine pseudogestational sac or decidual cyst may be
present