Clinical History
The patient is a 15 year old girl who presented with right lower quadrant (RLQ) pain, in addition to nausea and vomiting. Physical examination revealed RLQ tenderness to palpation. Abdominal and pelvic CT was performed to rule out appendicitis.
Imaging Findings
The CT revealed a large 12 x 6 x 5 cm, thick-walled, fluid-filled structure, extending from the right lower quadrant (RLQ) into the pelvis. The average fluid density was 33HU. The appendix was not identified. It appears that the uterine body was deviated to the left due to mass effect from the lesion. The right kidney was absent with compensatory hypertrophy of the left kidney.
Follow up pelvic ultrasound demonstrated complete separation of the uterine body into two parts. There was a relatively normal appearance of the left part, with abnormally distended right endometrial cavity by hypoechoic material. Further characterisation by MRI was recommended which confirmed findings of uterus didelphys complicated by atresia of the right cervix and associated haematometra. Based on findings, hysterectomy of the right uterine body and right tube was performed with sparing of the right ovary, without complications.
Discussion
Uterus didelphys is the least common uterine malformation, accounting for only five percent [1]. It is thought to be sporadic and multifactorial in nature. It occurs when the paramesonephric (Mullerian) ducts fail to fuse along the midline with subsequent regression of the septum, resulting in two uterine horns and cervices with non-communicating endometrial and cervical cavities [2]. It is not uncommon for women with uterus didelphys to also have renal abnormalities due to close embryological development. An obstructed, non-communicating uterine horn is always seen with ipsilateral renal agenesis [3].
Clinical manifestations become apparent post-menarche, usually with cyclical pelvic pain that can be mistaken for, or related to, endometriosis. Some women are not diagnosed until a hysterosalpingogram during an infertility evaluation. Having a uterine malformation is not, in itself, an infertility factor, although having a bicornate or didelphys uterus is associated with obstetrical complications such as intrauterine growth restriction and preterm birth [4].
Other differentials for uterine didelphys are bicornate uterus and septate uterus. A bicornate uterus will have communication of the two horns within the endometrial cavity, while a septate uterus will have a normal exterior anatomy with varying degrees of a midline internal endometrial septum. The initial imaging modalities of choice are 2D and 3D ultrasounds, with subsequent MRI (coronal and axial T2 WI) to distinguish these uterine malformations.
Recurring, cyclical pelvic pain due to the retention of menstrual blood in the obstructed uterine horn should be treated with surgical resection. Otherwise, a uterus didelphys does not necessarily require surgical correction.
Differential Diagnosis List
Uterus didelphys with cervical atresia and complicated by haematometra
Bicornuate uterus
Mucocele of appendix
Haematosalpinx
Fallopian tube malignant tumour
Final Diagnosis
Uterus didelphys with cervical atresia and complicated by haematometra
