Scar endometriosis is a term given to endometriosis occurring in a Cesarian section scar. It can be located in the skin, subcutaneous tissue, rectus muscle/sheath, intraperitoneally, or in the uterine myometrium (within uterine scar).
The reported incidence of abdominal scar endometriosis following Cesarean section is 0.03-0.6% 6.
Patients may complain of tenderness to palpation and a raised, unsightly hypertrophic scar. Most patients have cyclical pain (up to 70%) 5. The pain is usually intermittent and associated with the patient's menstrual cycle but it may be constant in nature. Some reports state that only as low as 20% of the patients exhibited cyclical symptoms. The overlying skin may be hyperpigmented due to deposition of hemosiderin. Some patients may be asymptomatic 4.
It is thought to be caused by implantation of endometrial stem cells at the surgical site at the time of uterine surgery.
For general imaging features of endometriosis: refer to the parent article.
Sonographic features are not specific. A subcutaneous nodule having relatively irregular borders, a heterogeneous echotexture with internal scattered hyperechoic echoes surrounded by a hyperechoic ring of variable width, and vascularity may be present. Occasionally cystic changes may be present 6.
Well-defined soft tissue nodule with heterogenous post-contrast enhancement and streaky appearance in the surrounding tissue.
The most sensitive imaging modality. Often accurately locates the lesion in relation to a previous C-section scar, with signal characteristics similar to that of background endometriosis.
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