It has been reported that endometrial lesions in the ovary have the potential for malignancy (10
). In the present case, endometrioid adenocarcinoma was shown to arise from endometriosis and the transition between endometriosis and endometrioid carcinoma was confirmed and met the criteria of Sampson and Scott (8
). This case was a female patient with a family history of ovarian and colon cancer who underwent a malignant transformation two years after pelvic clearance surgery, hysterectomy and bilateral salpingo-oophorectomy.
In the present case, five family members were diagnosed with cancer, two with ovarian cancer and three with colon cancer, as shown in . The results of these cases fulfill the Amsterdam II criteria and the Bethesda guidelines (Diagnosis criteria for HNPCC) (13
). A diagnosis of HNPCC should be considered (). Women with HNPCC have an increased risk of gynaecological cancer (14
). Among women with HNPCC, 20–60% may develop endometrial cancer compared with 3% of the general population. Ovarian cancer occurs in 10–20% women with HNPCC (15
). Additionally, according to Matalliotakis et al
, there is a relative risk for women with endometriosis and a positive family history of ovarian and colon cancer including first- and second-degree relatives (16
). The study indicated that HNPCC may be associated with gynaecological cancer. However, little evidence has been reported on the association between the malignant transformation of endometriosis and HNPCC. HNPCC is an autosomal dominantly inherited cancer disorder () and has been demonstrated to be caused by the inherited mutation of genes such as hMSH2, hMLH1, PMS1, PMS2 and hMSH6 (17
). The HNPCC gene mutations continue to develop and accumulate within neoplastic but not normal tissue (19
). However, associated studies have suggested that the malignant transformation of endometriosis may be induced by loss of heterozygosity (LOH) events on certain chromosomes such as the PTEN gene situated on chromosome 10q23.3 (20
). Whether certain special HNPCC gene mutations are involved in the malignant transformation of endometriosis remains unknown. In the present case, the malignant transformation of endometriosis may have arisen from the incomplete excision of the left ovary in the patient’s second surgery. The left ovary was identified as being markedly adhered to the colon during the patient’s second surgery. A meticulous excision was difficult to perform (22
), which may have resulted in a trace amount of residual left ovary. The blood supply of the residual ovary tissue may account for the formation of collateral circulation (24
). According to the levels of female hormones, the residual ovary was able to maintain normal endocrine function (23
). It has been reported that hyperestrogenism is closely associated with the malignant transformation of endometriosis (4
). In previously reported cases, women who underwent pelvic clearance surgery and later underwent estrogen replacement therapy had a markedly higher risk of malignant extra-gonadal transformation (4
). Hormonal factors may be crucial in the origin of endometriosis and the development of malignant transformation (4
). As discussed previously, the incomplete excision of the left ovary may have resulted in normal levels of serum estrogen. Whether the normal levels of female hormones contribute to the malignant transformation of ovary endometriosis has yet to be proved.
Clinical criteria for HNPCC.
As mentioned previously, we suggest that an accurate family history should also be obtained from women with endometriosis. As for women with HNPCC, hysterectomy and bilateral salpingo-oophorectomy should be considered as the patient’s first surgical treatment. Further studies of malignant endometriosis-associated gene detection in HNPCC should also be performed.