A Rare Occurrence of Endometriosis Externa Individually Within the Rectus Abdominis Muscle

Abstract

Endometriosis is defined as the presence of ectopic functional endometrial tissue outside the uterine cavity. It most commonly occurs in the pelvic organs, including the ovaries, ligaments of the uterus, and the pouch of Douglas. Extrapelvic implantation of endometrial tissue has also been reported in the literature. Extrapelvic endometriosis can be explained by lymphatic/vascular migration or mechanical transplantation of the tissue during surgery. Rectus abdominis muscle endometriosis is a rare phenomenon that usually presents with a palpable abdominal mass and cyclic pain. Ultrasonography (USG), computed tomography (CT), and magnetic resonance imaging (MRI) can be effective to define the location and size of the mass. Our patient was a 32-year-old woman presenting with cyclic abdominal pain and the development of an abdominal mass she had noticed for a year. USG and MRI scans revealed an endometrial focus in the right rectus abdominis muscle. Surgical excision with negative margins was performed, since surgical treatment of the lesion is offered as the definitive treatment.

Rectus Abdominis Endometriosis Following Cesarean Section: A Case Report

“…Various theories have been suggested to explain the etiology of endometriosis. The transplantation theory, widely recognized, hypothesizes that endometriosis develops from the retrograde transport of viable endometrial tissue during menstruation [ 6 , 7 , 9 , 12 , 13 ]. The coelomic metaplasia theory proposes that endometriosis stems from the transformation of peritoneal cells [ 6 , 9 , 12 , 13 ].…”

“…The coelomic metaplasia theory proposes that endometriosis stems from the transformation of peritoneal cells [ 6 , 9 , 12 , 13 ]. The induction theory, alternatively, suggests that the spread of shed endometrial tissue leads to endometriosis [ 7 , 10 , 12 ]. Moreover, the embryonic rest theory proposes that endometriosis is triggered by the activation of Müllerian origin cells [ 10 ].…”

“…The primary treatment for this condition is wide local excision, which necessitates the removal of at least 10 mm of normal tissue surrounding the lesion to reduce the risk of recurrence [ 2 , 7 , 9 , 17 ]. In rare instances, asymptomatic cases may be monitored without immediate intervention [ 15 ].…”

“…In rare instances, asymptomatic cases may be monitored without immediate intervention [ 15 ]. Historically, pharmacological treatments such as oral contraceptives, gonadotropin-releasing hormone (GnRH) analogs, progesterone, or danazol have been used with limited effectiveness as primary treatments [ 3 , 7 , 9 , 16 ]. However, these agents may serve as an alternative for patients who cannot undergo surgery or as adjuvant therapy to mitigate the risk of recurrence [ 7 , 9 , 16 ].…”

“…Historically, pharmacological treatments such as oral contraceptives, gonadotropin-releasing hormone (GnRH) analogs, progesterone, or danazol have been used with limited effectiveness as primary treatments [ 3 , 7 , 9 , 16 ]. However, these agents may serve as an alternative for patients who cannot undergo surgery or as adjuvant therapy to mitigate the risk of recurrence [ 7 , 9 , 16 ]. There has been a report of successful treatment of rectus abdominis endometriosis using sclerotherapy with ultrasound-guided ethanol injection [ 18 ].…”