Is Endometriosis a Truly Benign Disorder? Report of a Case of Intestinal Endometriosis with Lymph Node Metastasis

    

    

    Figure 2:  Magnetic resonance imaging (axial T2-weighted sequence)
showing dilated small bowel loops without any noticeable obvious cause.
    
    

The patient underwent an emergency exploratory laparoscopy: a stricture in the terminal ileum was detected. Consequently, a right colectomy with ileocolic anastomosis was performed. Her postoperative course was uneventful and she was discharged on the 6th postoperative day. Histological examination showed a polypoid nodule of 2 cm located in the terminal ileum, 3 cm proximal to the ileocoecal junction, with normal mucosa and retraction of the serosa. Histologically the nodule showed endometriosis invading the serosa, the muscular and submucosa layers, with no mucosal infiltration; one of the removed loco-regional lymph nodes showed endometrial growth.

Discussion

Endometriosis is defined by the extrauterine presence of endometrial tissue. This painful condition affects up to 15% of women of childbearing age, and nearly half of all infertile women, while 70% of women with chronic pelvic pain eventually will be diagnosed as having endometriosis [1]. Three main manifestations of this disorder have been described, namely adenomyosis, peritoneal endometriosis, and deep infiltrating endometriosis (DIE). The latest is considered the most severe form of the disease. Endometriosis can involve extra genital organs, the most common site being the intestinal tract, although the omentum, the peritoneum and other intra-abdominal organs can also occasionally be involved. Intestinal endometriosis begins with implantation of endometrial cells on the serosa surface: theses lesions can progressively invade the muscularis propria and the submucosa layers, while the mucosa is rarely affected [2]; as suggested by Chapron the endometriotic lesions that do not infiltrate beyond the serosa that usually remains asymptomatic, should be considered peritoneal endometriosis [3]. The endometriotic nodules should at least reach the muscularis to be defined as true intestinal endometriosis; these lesions may cause fibrosis and thickening of the bowel wall, resulting in stricture and mechanical bowel obstruction. Although the recto sigmoid colon is the commonest site of involvement, any part of the gastrointestinal tract can be affected, as the coecum, the appendix and the small intestine that can be involved in 3%, 3.6%, and 7%, of cases respectively [4].

Endometriosis is generally considered as a benign disease. Actually endometriosis, and in particular DIE, shares several traits with malignancy. When we consider a malignant disease we refer to a disorder hallmarked by the tendency to get worse progressively, to involve and invade other organs and tissues, to give rise to metastasis, and to bear anaplasia. All these features can be found in DIE.

DIE is a progressive disease and, even if it does not cause catabolic disturbance, metabolic consequences, or death, it tends to get worse progressively [5]. The ability of DIE, to invade adjacent tissue extensively has been demonstrated, particularly for bowel endometriosis [6].

Endometrial cells are capable of dissemination and metastasis along the same channels followed by endometrial adenocarcinoma. Endometriotic implants have been found in several areas of the body even far from the pelvis or the abdominal cavity such as in lungs, pleura and skin [7].

Endometriotic glands may be transported by lymphatic channels with subsequent lymph node involvement. Lymph node involvement in endometriosis is usually considered to be uncommon. However some studies emphasize that this event might be underestimated. The presence of endometrial tissue has been documented in uterine draining pelvic lymph nodes but also in other lymph nodes draining the rest of the pelvis [8]. Noel found lymph node involvement in 42.3% of cases after recto sigmoid resection for endometriosis, with one to four lymph nodes affected in each specimen. Moreover the lymph node–positive status correlated significantly with the number of retrieved lymph nodes suggesting that a more radical surgical resection may reveal a higher rate of lymph node involvement [9]. Similar findings were reported by Abrao who found affected lymph nodes in 26.3% of patients after recto sigmoidectomy for endometriosis [10].

Lastly endometriosis demonstrates somatically acquired genetic alterations similar to those found in cancer, leading to clonal expansion of genetically abnormal cells [11,12].

The significance of such findings is still unknown and, even if require further investigation, they point out the systemic aspect of the disease.

Conclusion

Lymphatic spread of endometriosis, together with other features, underlines the potential malignant feature of this disease. Further studies are required to better clarify the pathogenesis and the behavior of endometriosis and therapeutic implications.

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