Presentation
Incidental adnexal mass. Referred by OBGYN for pelvic MRI.
Patient Data
Large echogenic pelvic mass occupying the rectouterine space, anteriorly displacing the uterus, with extensive posterior acoustic shadows, suggestive of intralesional calcifications, with multiple intralesional interrupted linear echogenic bands.
The lesion is devoid of internal vascularity on color Doppler interrogation (not shown).
Large complex right ovarian cystic lesion occupying the rectouterine space with an intralesional fat-fluid interface. No enhancing invasive soft-tissue components are seen on the contrasted study. It contains two large relatively ill-defined rounded lesions of predominantly fat signal intensity with multiple low and high signal-intensity structures, suggestive of calcifications and hair.
This complex cyst exhibits considerable mass effect upon the adjacent structures.
Multiple dilated parametrial venous channels are present, more pronounced on the left side, with associated left ovarian vein dilatation, suggestive of pelvic congestion.
IUCD in situ.
Tiny incidental synovial herniation pit in the right femoral metaphysis.
Case Discussion
This case nicely demonstrates the Rokitansky nodule (dermoid plug) seen within a Mature cystic ovarian teratoma.
Mature cystic teratomas of the ovary (dermoid cyst) are formed of well-differentiated components of two or more of the germ cell layers (ectoderm, mesoderm, endoderm). They are the most common surgically resected ovarian neoplasm and the most common ovarian tumor in children.
They are usually asymptomatic. However, they can present with nonspecific abdominal pain. They are bilateral in around 10% of cases.
These lesions have variable appearances on ultrasound, depending on the overall internal constituents. They are easily diagnosed on CT and MRI, since these modalities are more sensitive to fat.
Mature cystic teratomas can be complicated by ovarian torsion (most common complication) if large in size. A far less common complication is rupture with secondary granulomatous peritonitis in less than 1% of patients.
Malignant transformation into squamous cell carcinoma is rare, occurring in 1-2% of cases.