chocolate cyst

Endometriomas, also known as chocolate cysts or endometriotic cysts, are a localized form of endometriosis and are usually within the ovary. They are readily diagnosed on ultrasound, with most demonstrating classical radiographic features.

Epidemiology

These occur in women of reproductive age.

Pathology

Endometriomas contains dark degenerated blood products following repeated cyclical hemorrhage. The cysts may be up to 20 cm in size although they are usually smaller (2-5 cm).

Location

Typical locations include:

• ovaries: ~75%
• anterior/posterior cul-de-sac: ~70%
• posterior broad ligament: ~50%
• uterosacral ligaments: ~35%
• uterus: ~10 %
• colon: ~5%

Radiographic features

Plain radiograph

Not usually helpful in diagnosis; ~10% of endometriomas can calcify.

Ultrasound

The appearances of endometriomas can be quite variable. The classical example is a unilocular cyst with acoustic enhancement with diffuse homogeneous ground-glass echoes as a result of the hemorrhagic debris. This appearance occurs in 50% of cases .

Less typical features include :

• multiple locules (~85% will have <5 locules)
• hyperechoic wall foci (present in 35%)
• cystic-solid lesion (~15%) or purely solid lesion (1%)
• anechoic cysts (rare; 2%)

MRI

Signal characteristics vary according to the age of any complicating hemorrhage :

• T1
  • typically, lesions appear hyperintense while acute hemorrhage occasionally appears hypointense
  • endometriomas with high T1 signal characteristically do not show loss of signal on T1 fat suppressed sequence, which is important for differentiating it from mature cystic teratoma of the ovary
• T2
  • typically hypointense owing to the presence of deoxyhemoglobin and methemoglobin (shading sign), which is very suggestive of endometrioma
  • T2 dark spot sign is specific for chronic hemorrhage and is helpful in diagnosing endometriomas
  • old hemorrhage occasionally appears hyperintense
• DWI
  • variable restricted diffusion
• T1C+
  • may have wall enhancement
  • the presence of an enhancing mural nodule is suggestive of malignant transformation

Treatment and prognosis

Although endometriomas are usually a benign entity, there is an ~1% rate of malignant transformation. Endometrioid tumors of the ovary and clear cell adenocarcinoma are the most common histological pattern seen . They are mostly seen in women >40 years after several years of latency, with endometriomas larger than 9 cm . Malignant transformation is uncommon in masses <6 cm.

If not surgically excised, follow-up should be at least yearly . GnRH agonists may be used for medical management.

Differential diagnosis

General imaging differential considerations include:

• hemorrhagic ovarian cyst
  • brighter on T2-weighted images
  • an absence of the "shading sign"
• ovarian dermoid cyst
  • will show fat suppression on fat suppressed sequences on MRI
• cystic neoplasm
• tubo-ovarian abscess

Siehe auch:

• eingeblutete Ovarialzyste
• Tuboovarialabszess
• Dermoidzyste
• ovarian mucinous tumours
• MRI protocol - endometriosis
• Endometriose der Appendix
• Endometriose im Processus vaginalis peritonei
• cystic neoplasm
• invasive Endometriose
• Endometriose am Urachus
• Endometriose Rektum
• Endosalpingiose
• Endometriose des Ureters
• reifes zystisches Teratom des Ovars

und weiter:

• Dünndarmileus
• Ileitis terminalis
• Splenose
• Uterus didelphys
• vegetable and plant inspired signs
• Ovarialtorsion
• ovaries
• Endometriose nach Kaiserschnitt
• ovarian ectopic pregnancy
• shading sign
• Hämatosalpinx
• infertility in the exam
• haematosalpinx
• Endometriose des Colon sigmoideum
• CA 125 elevation
• pelvic MRI protocol Endometriosis
• mesonephroid carcinoma of the ovary
• ovarian lesions with T2 hypointensity
• Haemoperitoneum
• obstruierte Hemivagina und ipsilaterale renale Anomalie (OHVIRA) Syndrom
• sampson syndrome
• Endometriose des Ovars
• pelvic endometriosis
• gynäkologisch radiologisches Curriculum
• uterine artery embolisation : MRI assessment
• haemorrhagic corpus luteal cyst
• Ovar
• pelvic masses in female
• Uteruszysten
• endometrioma carcinoma
• rupturiertes Endometriom
• intestinal endometriosis
• submuköser Tumor des Rektums
• Endometriose der Harnblase
• multizystisches Mesotheliom