·         Low lying cecum- This may mimic an ovarian dermoid. Repeat examination after an enema may reveal its true nature.

·         Fluid/feces filled bowel- Demonstrate changes with penstalsis. Reverberation echoes from gas can be mistaken for margins of a mass.

·         Bladder duplication artifact- This may give rise to pseudomass effect; may be resolved by partial voiding.

·         Hydrosalpinx/pyosalpinx- These may present cystic, solid or complex masses in relation to the adnexa.

·         Vascular aneurysms/ malformations-These show characteristic flow on pulsed Doppler.

·         Uterine masses- These may present as adnexal masses. Normally ultrasounc should be able to differentiate the uterus from the mass.

 

·         Paraovarian-They arise from the mesovarium. Separate from the ovary.

 

 

·         Pelvic kidneys- They have a reniform shape and usually recognizable parenchymal structure. They may become hydronephrotic.

 

·         Psudomyxoma peritonei-This can give rise to a gelatinous material that may implant on serosal surfaces.

 

 

·         Pelvic fat and connective tissue-Any of these structures may be confused with the ovaries. Confusion may be less likely with TVS.

 

·         Presacral masses- Their dorsal location may be identified with a water enema technique and computed tomography.

 

 

·         Lymphocele and hematoma-These resemble adnexal cysts and may be difficult to differentiate from gynecologic masses.

 

·         Colonic carcinoma-These may present as an ‘atypical target sign’. Recurrence after surgery may be difficult to differentiate.

 

 

·         Diverticular abscess/mass- US may reveal bowel wall thickening or fluid surrounding a ‘target sign’.

 

·         Markedly constipated bowel/reMay mimic a dermoid. Rectal examination may identify the cause.

 

 

·         Matted omentum- polypoid fatty masses which may mimic adnexal tumors. With TVS confusion is less likely.

 

·         Obturator internus- May be mistaken for an ovary; this muscle usually lies more posteriorly.

 

 

·         Peritoneal inclusion cysts- Patients usually have a history of previous pelvic surgery. US findings are those of an anechoic septate mass surrounding the ovary. Doppler sonography shows low resistive flow in the septations.

 

 

 

NB- the normal ovary is mobile and may change.