Endometrioid carcinoma of the fallopian tube misdiagnosed as an infected endometrioma: A case report

This concerns a 49-year-old patient, single, with no personal or family history, who presented with chronic pelvic pain associated with menorrhagia. The clinical examination revealed a patient in fairly good general condition with normal vital signs. Physical examination of the abdominopelvic area showed an enlarged and globular uterus, equivalent to 17 weeks of gestation. The rest of the somatic examination was unremarkable. Pelvic ultrasound showed an enlarged myomatous uterus, the right ovary was not visualized, the left ovary showed a 12*9 cm cystic, multi-septated mass, non-vascularized on Doppler. No fluid in the pouch of Douglas was seen. An abdominopelvic MRI revealed an enlarged and polymyomatous uterus, a focus of posterior isthmic adenomyosis associated with a focus of deep endometriosis at the torus with adherence of both ovaries posteriorly, a 62 mm right ovarian endometrioma, and a 135 mm left ovarian cystic formation with thick walls, multicystic, requiring histological verification. There was no ascites, lymphadenopathy, or carcinomatosis peritonitis noted. The serum Cancer Antigen (CA) 125 level was normal (34 U/ml [normal<35 U/ml]). The patient requested radical treatment and did not wish to retain her uterus. She underwent exploratory laparotomy. In the exploratory laparotomy, an adherent retro and supra-uterine mass involving the uterus, both adnexa, and the digestive tract was found. Careful adhesiolysis was performed, releasing the adnexa. The left adnexa showed a formation suggestive of an infected endometrioma. A total hysterectomy with bilateral adnexectomy and peritoneal washing was performed. The patient received intravenous antibiotics. The postoperative course was uneventful. The histological result found, at the level of the left tube, an intra-mucosal tubal epithelial proliferation incidentally discovered compatible with a confined endometrioid tubal carcinoma to the tubal mucosa without exceeding it, classified as pT1a according to FIGO guidelines. The carcinoma was associated with severely inflammatory fibro-connective tissue indicative of an abscess capsule. The case was deliberated upon during the Multidisciplinary Tumor Board Meeting, where it was determined that there were no indications for lymphadenectomy or additional treatment. Close surveillance was recommended. Consequently, the patient did not undergo adjuvant treatment and received regular follow-up appointments. After a year of follow-up, she had good locoregional control, with staging indicating no evidence of recurrence or metastasis.

Imen Hamra, Ahmed Halouani, Hajer Sebri, Amel Triki, Anissa Ben Amor: Patient management. Imen Hamra, Ahmed Halouani, Hajer Sebri: writing the manuscript.

Ethical approval for this study was provided by the Ethical Commitee Of Mongi Slim University Hospital, Tunisia.

The authors declare that there are no sources of funding in this research.

Appropriate consent permission and release were obtained to include case details.

This case report was not registered.

Imen Hamra

Tubal cancer is a rare cancer of unknown etiology, underestimated, and sometimes confused with ovarian pathology. Preoperative diagnosis is difficult because the clinical picture is polymorphic and imaging is nonspecific. Due to its unpredictable nature, fallopian tubal cancer should be considered in the differential diagnosis of peri- and postmenopausal women who present with unexplained uterine bleeding, pelvic pain, adnexal mass and complicated pelvic inflammatory disease. The endometrioid form is exceptional and controversial in its etiopathogenesis. The connection of endometriosis and endometrioid cancer remains controversial. Treatment parallels that of malignant epithelial ovarian tumors, with prognosis depending on FIGO stage and histological type.

Fallopian tube cancer is a rare tumor, representing between 0.3 and 1.8 % of all malignant tumors in the gynecological sphere [ 1 , 2 , 4 ]. This low prevalence is likely underestimated [ 3 ]. It is difficult to distinguish these tumors, when they extend to neighboring organs (advanced forms), from ovarian or uterine tumors with secondary tubal extension. The most frequent histological type is adenocarcinoma. It most often occurs in the glandular cells lining the fallopian tubes and is similar to serous ovarian carcinoma. Rare types of fallopian tube cancer can also occur. These include clear cell carcinoma, endometrioid carcinoma, adenosquamous carcinoma, squamous cell carcinoma, and sarcoma [ 5 ]. The endometrioid form is exceptional and controversial in its etiopathogenesis [ 13 , 14 ]. Diagnosis mostly occurs incidentally during histological examination. This report details a case of endometrioid carcinoma of the fallopian tube, which was discovered incidentally during histological examination following total hysterectomy with bilateral annexectomy. Several risk factors have been suggested to explain the occurrence of fallopian tube cancer: BRCA1 and BRCA2 chromosomal mutations, PID (pelvic inflammatory disease): chronic tubal infection or salpingitis as well as genital tuberculosis. The role of endometriosis remains controversial [ 14 ]. No significant correlation with age, ethnicity, weight, infertility, or smoking has been demonstrated [ 4 , 6 ]. The symptoms are vague and nonspecific: hydrohematometra, pelvic pain, and lateral-uterine swelling, forming a triad of associated but inconsistent symptoms of the disease [ 5 ]. In our case, the patient presented with chronic pelvic pain and metrorrhagia, which were taken into account in connection with an adenomyotic uterus with endometriosis lesions. Inflammatory processes and the proximity of the tubo-ovarian relations exacerbate the diagnostic problem. Tubal carcinoma has no pathognomonic hallmark on ultrasound and is therefore difficult to recognize [ 7 , 8 ]. The picture is that of a nonspecific heterogeneous adnexal mass, with irregular and blurred contours or thick walls, whose malignancy is confirmed by the demonstration of distant dissemination. In our case, pelvic ultrasound revealed a 12*9 cm cystic and multi-septated mass on the left side of the uterus. Abdominopelvic MRI further identified a 135 mm left ovarian cystic formation with thick walls and multicystic features, necessitating histological verification. These findings were associated with endometriosis lesions. Diagnosing fallopian tubal carcinoma preoperatively could be aided by measuring serum CA-125 levels. It is very sensitive in this pathology. Unfortunately, it is not specific. In advanced tumor stages, elevated serum levels (> 35 U/ml) may be found, which decrease during remission phases, only to become elevated again in case of disease progression. CA125 can be used for monitoring these patients [ 8 ]. The treatment of tubal cancers is often confused with that of malignant epithelial ovarian tumors [ [9] , [10] , [11] , 12 ]. Treatment is essentially surgical. Adjuvant chemotherapy based on cisplatin and/or radiotherapy is recommended respectively in advanced cases associated with distant or confined peritoneal metastases to the pelvis. The prognosis for tubal cancers is better than that for malignant ovarian tumors, as they are most often diagnosed at an earlier stages, but also at an equal stage. The overall 5-year survival of tubal malignant tumors ranges from 44 % to 56 %, as they are often diagnosed at earlier stages or sometimes at comparable stages. The overall 5-year survival rate for tubal malignant tumors ranges from 44 % to 56 %, as reported in major studies, and depends on various prognostic factors such as FIGO stage, histological type, and patient age. Endometrioid carcinoma typically carries the most favorable prognosis among tubal cancers. Conversely, involvement of the tubal serosa, ovaries, uterus, or other pelvic and abdominal structures indicates a poorer prognosis. In our case, the small size of the tumor and its confined, intraepithelial nature limited to the fallopian tube are favorable prognostic factors.

Fallopian tube cancer is a rare tumor, representing between 0.3 and 1.8% of all malignant tumors in the gynecological sphere [ 1 , 2 ]. Due to the proximity of the uterus and ovary, diagnosing primary fallopian tube cancer is very difficult and relies on strict criteria. The endometrioid form is exceptional and controversial in its etiopathogenesis [ 13 , 14 ]. Only a few cases have been previously reported. Diagnosis mostly occurs incidentally during histological examination. This case presents a distinctive aspect with the rare occurrence of endometrioid-type fallopian tube cancer, notably associated with endometriosis, and initially misdiagnosed as an infected endometrioma. It underscores the diagnostic complexities encountered in identifying primary endometrioid fallopian tube cancer. The work presented in this study has been reported in accordance with the SCARE (Surgical Case Report) criteria [ 15 ].

The authors declare that they have no competing interest.