**2. Pathogenesis**

Endometriosis is doubtless a multifactorial disease.

The most widely accepted theory of arising of the endometriosis is an implantation of endometrial fragments brought by retrograde menstrual flow in a peritoneal surface (50). This should be typical for intraperitoneal lesions.

Meyer**'**s theory explains the origin of endometriosis by celomic metaplasia mainly in the ovaries, peritoneum and urinary bladder due to their common development from the celomic epithelium. Mesenchymal cells with retained multi-potential under the properties circumstances undergo metaplasia into endometriotic cells. This theory may explain the incidence of endometriosis in women with uterine agenesis or in males treated by estrogens (3).

Endometrial Tumors in Postoperative Scars - Pathogenesis, Diagnostics and Treatment 87

localizations (56). After invasion the endometrial cells are producing growth factors and cytokinins, such as vascular endothelial growth factor (VEGF), macrophage colony stimulating factor (MCSF) and a lot of others, what stimulates neovascularization of the

The role of genetics (32) and exogenous environmental pollutants (47) as contributing

The disease is uncommon but not so rare. The extraperitoneal localizacion of the lesion is mainly the abdominal wall scar, but should be also in episotomy scar, bowel, bladder, lung, kidneys, brain, umbilicus, groin (29) and even in male urinary tract (51). Leite et al. (38) mentioning except those liver, extremities and pericardium, confirm the opinion that extrapelvic endometrioma occurs mainly as a complication of cesarean section, hysterectomy and episiotomy. Akagi et al. (2) reported an asymptomatic case of endometriosis of the appendix. Endometriosis in the inguinal channel usually occurs on the right side (90%) and in 32% may be associated with an hernia (15, 20). This feature seems to be due to the clockwise circulation of the peritoneal fluid and to the presence of sigmoid colon that shields the left inguinal ring (20). Vulvar involvement of endometriosis is extremely rare. Buda et al. (8) described a case of endometriosis in a scar after excicion of the

According to Chaterjee (11) endometriosis of the abdominal wall occurs in 0,03 – 1,08% of women with previous history of obstetric or gynecologic procedures. Leite et al. (38) reviewing bibliography estimates the incidence of abdominal wall endometrioma on 0,03 – 3,5%. Nominato et al. (41) in their large series report the incidence of scar endometrioma in 0,2% women submitted former to cesarean section but only in 0,06% when episiotomy was made. Singh et al. (52) reported three cases, considering that the true incidence of this disease (0,8%) is underestimated because a lot of cases remains undetected. Agarwal and Fong (1) reporting 10 cases (among them six in Pfannenstiel scar) estimate the frequency of cutaneous localization of disease 1,1%. Unusually high percent (5,2%) of cutaneous

Concerning the coincidence of peritoneal and abdominal wall endometriosis das Chagas Medeiros et al. (10) basing on literature data estimates the frequency of abdominal wall endometriosis on about 0,5 – 1% in women with pelvic endometriosis. According to another data in 13% both of the forms of disease are present (29), more often by spontaneous

The diagnosis of endometriosis in the postoperative scars is usually established basing on characteristic clinical symptoms as the presence of slowly developing immobile lump, which seems to be attached to the anterior fascia, in the scar or near of them, often swelling during menstruation and painful, especially in this period in most of cases. Sometimes occurs periodical bleeding from the superficial lesions and lower abdominal pain (1, 4, 29). The boundary of the mass is not clear usually. Incision of it looks grey or slightly yellowish (59). Leite et al. (38) in turn, describe it as whitish fibrous tumor with thick chocolate-like

localization of endometriosis was reported from Glasgow (18).

abdominal wall endometriosis without any previous surgery (1).

lesions and further development (25).

**3. Occurrence and diagnostics** 

factors is also considered.

Bartholin gland.

colored liquid areas.

Vascular dissemination theory (27), in turn, with endometrial cells spread into blood or lymphatic circulation may explain distal locations of endometriosis. Very interesting was one of cases described by Agarwal and Fong (1). This Chinese woman suffering from sterility and a lump in right inguinal region had twice laparoscopy and ablation of endometriotic intraperitoneal lesions without managing of the lump. Third laparoscopy revealed endometriotic deposits along the right round ligament contiguous with this lump which was afer excision diagnosed as an endometrioma. It may be speculated, that in some conditions endometriotic cells can infiltrate per continuitatem like a malignant tumour.

The etiopathogenetic mechanism of endometriosis localized in surgical scars would be related to iatrogenic transplantation of endometrium during delivery or surgery, mostly gynecological.

All the mentioned above theories could only elucidate mainly the way on which endometrial cells or fragments could be transported to their improper localizations. But still remains unclear why in these places the endometrial cells survive and proliferate.

Endometriosis is defined as a steroid-dependent condition with a particular genetic background (37). It is well known, that estrogens promote the development of endometriotic lesions and anti-estrogen or gestagen therapy can diminish the symptoms.

There is substantial evidence that not only hormonal but first of all immunologic factors play a role in the pathogenesis of endometriosis (3, 54, 56). Immune alterations include increased number and activation of macrophages, decreased T cells reactivity and NK cells cytotoxicity, increased circulating antibodies and changes in the cytokine system. These alterations are responsive for implantation and survival of the ectopic endometrial cells and concomitant inflammatory reaction and pain. Increased oxidative stress appears to be a common contributory factor in the pathogenesis of endometriosis (3). Wicherek et al. (56) in discussion consider that endometral cells are implanted in ectopic places usually during the maintenance of higher immunotolerance, including pregnancy. The ectopic endometrium preserves the ability to undergo reversible decidualization. Once implanted develops further when estrogens level raise with a concomitant lack of adequate progesterone level.

The next factor, playing a potent role are endometrial stromal cells themselves. When stimulated by estrogens the endometriotic cells may proliferate until they become symptomatic. Moreover, endometriotic lesions can thanks to aromatase activity produce estrogens locally themselves (9).

It is known, that in patients suffering from endometriosis higher activity of integrins and cadherin E on surface of endometrial and mesothelial cells is expressed (24). This may explain the better ability of adhesion of these cells in another places than uterine cavity. The invasion of them is enhanced by metalloproteinases. It was shown, that in patients with endometriotic lesions even eutopic endometrium expresses higher activity of matrix metalloproteinase -2 (MMP-2) whereas lower of tissue matrix metalloproteinase inhibitor – 2 (TIMP-2) (14). The ability of endometrial cells to regulate the cytotoxic immune activity by expression of factors such as RCAS 1 or metallothionein enables their survival in ectopic localizations (56). After invasion the endometrial cells are producing growth factors and cytokinins, such as vascular endothelial growth factor (VEGF), macrophage colony stimulating factor (MCSF) and a lot of others, what stimulates neovascularization of the lesions and further development (25).

The role of genetics (32) and exogenous environmental pollutants (47) as contributing factors is also considered.
