Lymphatic spread of endometriosis to pelvic sentinel lymph nodes: a prospective clinical study

Primary Retroperitoneal Carcinomas: New Insights into Pathogenesis and Clinical Management in Comparison with Ovarian Carcinomas and Carcinoma of Unknown Primary

Primary retroperitoneal carcinomas are very rare tumors. Their pathogenesis remains unknown but may be associated with that of ovarian carcinomas, considering the similarity in morphology and gender preference. Although metaplasia of coelomic epithelium is the most widely accepted theory, the pathogenesis of retroperitoneal carcinomas may differ by histologic subtype, like ovarian carcinomas. Mucinous carcinoma, which develops in both women and men, may originate in both primordial germ cells and Walthard cell nests that may be derived from the fallopian tube. Serous carcinomas may be associated with endosalpingiosis, the presence of fallopian tube-like epithelium outside the fallopian tube, and a remnant Müllerian tract. Endometrioid and clear cell carcinomas appear to be associated with extraovarian endometriosis. Additionally, both carcinomas in the retroperitoneal lymph nodes may be metastatic diseases from endometrial and/or renal cell cancer that regress spontaneously (carcinoma of unknown primary). Retroperitoneal carcinomas are difficult to diagnose, as they have no characteristic symptoms and signs. Surgery is the cornerstone of treatment, but the necessity of chemotherapy may depend on histological subtype. Further studies are necessary, in particular studies on endosalpingiosis, as endosalpingiosis is a poorly understood condition, although it is associated with the development of both serous and mucinous carcinomas.

Sox-2 positive cells identified in lymph nodes from endometriosis patients may play a role in the disease pathogenesis

OBJECTIVE

This study aimed to characterize Sox-2 in sentinel lymph nodes and randomly obtained lymph nodes from endometriosis (EM) patients for the first time.

STUDY DESIGN

This prospective study analyzed tissue samples from surgical specimens collected from May until December 2007 in the Endometriosis Center Charité, Berlin. Lymph node samples from 38 women aged between 22 and 49 years who underwent laparoscopy due to symptomatic EM were analyzed. The material was obtained either randomly or, in the case of deep infiltrating endometriosis, detected using 4 cc Patent Blue®, labeled intraoperatively, which made the sentinel lymph nodes available for histological examination. Together with hematoxylin and eosin staining, the sections were evaluated by immunohistochemistry with antibodies against estrogen and progesterone receptors and Sox-2. Using double-immunofluorescence microscopy, the colocalization of Sox-2 and estrogen receptors were evaluated.

RESULTS

Sox-2-positive cells were identified in the lymph nodes' cortical and medullary zones, with a higher expression in the medullary layer. Occasionally, Sox-2 positive stained cell groups, called cell nests, could also be detected. The number of Sox-2 positive cells in the sentinel lymph nodes was almost three times higher than in the random lymph nodes (p = 0.031). A significant five-fold increase (p = 0.0013) in Sox-2 expression was seen in the estrogen and progesterone receptor (ER/PR) positive patient group compared to the progesterone receptor positive group or hormone receptor negative patients. Identical hormone-related Sox-2 expression was also detected separately for the sentinel lymph node group (p = 0.0174). Sox-2 showed pronounced colocalisation with estrogen receptors.

CONCLUSION

The lymphatic involvement in EM is evidence of a systemic disease manifestation and provides evidence of an immune system failure. In recent years, many theories have been studied, but there is no single theory that could explain all aspects of EM. The future concept of EM is likely to incorporate the elements from all the pathogenetic theories already described. Through this study, stem cells and lymphatic metastasis theories were incorporated.

Endometriosis in para-aortic lymph node resembling a malignancy: a case report and literature review

Background

Endometriosis is a common benign gynecological disease characterized by growing-functioning endometrial tissue outside the uterus. Extra-pelvic endometriosis, which accounts for approximately 12% of endometriosis, is more challenging to diagnose because of its distance from the pelvic organs. Halban's theory of benign metastasis indicates that endometrial cells can appear in extra-pelvic organs via lymphatic and blood vessels, but endometrial lymph node metastasis cases are still rare. We report a case of endometriosis in a para-aortic lymph node whose clinical behavior mimicked a malignancy.

Case presentation

A 52-year-old perimenopausal woman underwent laparoscopic hysterectomy plus bilateral salpingectomy (the patient insisted on the preservation of her ovaries) at a local hospital 2 years earlier because of adenomyosis. The patient presented with a complaint of low back pain to the gastrointestinal outpatient department of our hospital. The carbohydrate antigen 125 (CA125) was abnormally elevated at 5280.20 U/ml, human epididymis 4 (HE4) was 86.0 pmol/L, while other tumor markers were normal. Serum female hormone results were in the postmenopausal range, and her gastroenteroscopy showed no abnormalities. Moreover, both enhanced magnetic resonance imaging and positron emission tomography-computed tomography showed a high possibility of a retroperitoneal malignant lymph node (metastasis possible, primary site unknown). One week after admission, she underwent laparoscopic exploratory surgery, during which we observed normal shape and size of both ovaries while the left ovary was cystic-solid. After opening the retroperitoneal space, an enlarged lymph node-like tissue measuring 8 × 4 × 3 cm³ was found near the abdominal aorta. When the surrounding adhesions were separated, lymph node-like tissue was poorly demarcated from the abdominal aorta and renal artery. Some lymph node samples and left ovary were sent for intraoperative frozen section, which revealed benign lesions, similar to endometrial tissue. The lymph node tissue was then excised as much as possible, and the second set of intraoperative frozen sections showed high probability of endometrial tissue. The final histopathology and immunohistochemistry staining reached a diagnosis of para-aortic lymph node endometriosis. Gonadotropin-releasing hormone antigen treatment was recommended every 28 days because of the high preoperative CA125 and imaging-based suspicion of malignancy. The serum CA125 subsequently decreased to normal levels, and no para-aortic lesions were detected on abdominal enhancement CT. She is being followed up regularly.

Conclusion

It is known that the incidence of lymph node metastasis in pelvic endometriosis is relatively rare. Our report shows that endometriotic tissue can metastasize via the lymphatic route and suggests that endometriotic tissue has the characteristics of invasion and metastasis.

Endometriosis of para-aortic node masquerading a malignancy: a rare occurrence

Endometriosis is a benign estrogen-dependent disorder affecting women in their reproductive age group. Endometriosis means 'abnormal growth of endometrial glands' outside the uterus. Multiple theories on aetiopathogenesis of endometriosis have been postulated, Halban's theory on 'Benign Metastasis' which proposed the presence of endometriotic cells in lymphatic vessels and lymph nodes provides the basis of this case report. Here, we report a case of 26-year-old nulliparous woman who presented with grossly elevated CA 125 with endometriosis in her para-aortic nodes mimicking as ovarian cancer.

Extracellular vesicle-associated VEGF-C promotes lymphangiogenesis and immune cells infiltration in endometriosis

Endometriosis is a highly prevalent gynecological disease with severe negative impacts on life quality and financial burden. Unfortunately, there is no cure for this disease, which highlights the need for further investigation about the pathophysiology of this disease to provide clues for developing novel therapeutic regimens. Herein, we identified that vascular endothelial growth factor (VEGF)-C, a potent lymphangiogenic factor, is up-regulated in endometriotic cells and contributes to increased lymphangiogenesis. Bioinformatic analysis and molecular biological characterization revealed that VEGF-C is negatively regulated by an orphan nuclear receptor, chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII). Further studies demonstrated that proinflammatory cytokines, via suppression of COUP-TFII level, induce VEGF-C overexpression. More importantly, we show that functional VEGF-C is transported by extracellular vesicles (EVs) to enhance the lymphangiogenic ability of lymphatic endothelial cells. Autotransplanted mouse model of endometriosis showed lenvatinib treatment abrogated the increased lymphatic vessels development in the endometriotic lesion, enlarged retroperitoneal lymph nodes, and immune cells infiltration, indicating that blocking VEGF-C signaling can reduce local chronic inflammation and concomitantly endometriosis development. Evaluation of EV-transmitted VEGF-C from patients' sera demonstrates it is a reliable noninvasive way for clinical diagnosis. Taken together, we identify the vicious cycle of inflammation, COUP-TFII, VEGF-C, and lymphangiogenesis in the endometriotic microenvironment, which opens up new horizons in understanding the pathophysiology of endometriosis. VEGF-C not only can serve as a diagnostic biomarker but also a molecular target for developing therapeutic regimens.

The Lymphatic System in Endometriosis: a Pilot Study of Endometrial-Like Cells and Immune Cell Populations in Lymph Nodes Associated with Deep Infiltrating Bowel Lesions

In endometriosis, the lymphatic and immune systems are implicated in disease establishment and progression. The objective of this pilot study was to examine endometrial-like, and for the first time, immune cell populations in lymph nodes associated with deep infiltrating endometriosis (DIE) bowel lesions. Premenopausal women undergoing excision of endometriosis and/or hysterectomy were included. DIE bowel lesion-associated (n = 10) and other pelvic (n = 15) lymph nodes were studied. Samples were immunohistochemically stained for endometrial-like cells (CD10), T cells (CD3, CD4, CD8, and FoxP3), dendritic cells (DC; DC-Lamp and DC-Sign), B cells (CD20, CD79 and plasma), macrophages (CD68), and natural killer cells (NK; CD57). Cell abundance (percentage positive area) and antigen expression (optical density; OD) were quantified. Endometrial-like cells and each immune cell population were present in all studied nodes. The DIE bowel lesion-associated nodes showed features of immune activation, with T cell proliferation (CD3+ area p = 0.007, CD4+ area p = 0.015 compared with other pelvic nodes); and a mixture of helper and regulatory T cells, B cells, DCs, macrophages, and plasma cells present in the paracortex. In DIE bowel lesion-associated compared with other pelvic nodes, CD10+ endometrial-like cells were reduced (percentage positive area p < 0.001, OD p = 0.004). This study provides new insight into lymphatic and immune system involvement in advanced endometriosis. In particular, we have shown evidence of immune activation in DIE lesion-associated nodes. This was despite lower endometrial-like cell numbers compared with other pelvic nodes. The observations contribute to a developing understanding of the local immune response to advanced disease.

Postmenopausal endometriosis, where are we now?

PURPOSE OF REVIEW

Postmenopausal endometriosis is a gynecologic disease, affecting 2-5% of postmenopausal woman. Current literature assessing the prevalence, pathogenesis, and treatment of this uncommon condition is limited, stressing the necessity for future research. This review examines the current literature on postmenopausal endometriosis to help inform clinical decision-making and point to novel approaches for treatment and management.

RECENT FINDINGS

Although one unifying theory to explain the pathogenesis of endometriotic lesions has not been elucidated, estrogen dependence is central to the pathophysiological process. The total quantity of estrogen production is mediated by multiple enzymes in complex pathways. Recent studies have confirmed the presence of these necessary enzymes in endometriotic lesions thereby suggesting a local source of estrogen and a likely pathogenic contributor. More research is needed to fully elucidate the mechanism of local estrogen biosynthesis; however, the current data provide possible explanations for the presence of postmenopausal endometriosis in an otherwise systemically hypoestrogenic environment.

SUMMARY

All suspected endometriosis lesions should be surgically excised for optimization of treatment and prevention of malignant transformation. If hormone replacement therapy is initiated, combined estrogen and progestin is recommended, even in the setting of previous hysterectomy, given the risk of disease reactivation and malignant transformation of endometriotic lesions. Further research is needed to understand the true prevalence, cause, and progression in this patient demographic. Histologic studies evaluating tissue lesions and peritoneal fluid for estrogen receptors, estrogen metabolizing enzymes, immune cells, and nerve fibers will aide in clinical management and treatment planning.

Molecular and Cellular Pathogenesis of Endometriosis

BACKGROUND

A substantial body of studies supports the view that molecular and cellular features of endometriotic lesions differ from those of eutopic endometrium. Apart from that, evidence exists that the eutopic endometrium from pa-tients with endometriosis differs from that of females without endometriosis.

OBJECTIVE

Aberrant expression profiles include a number of non-steroid signaling pathways that exert their putative influ-ence on the pathogenesis of endometriosis at least in part via crosstalk(s) with estrogen-mediated mechanisms. A rational to focus research on non-steroid signal pathways is that they might be remunerative targets for the development and selection of novel therapeutics to treat endometriosis possibly without affecting estrogen levels.

RESULTS AND CONCLUSION

In this article, we describe molecular and cellular features of endometriotic lesions and focus on the canonical WNT/β-signaling pathway, a key regulatory system in biology (including stem cell homeostasis) and often in pathophysiological conditions such as endometriosis. Recently emerged novel biological concepts in signal transduction and gene regulation like exosomes and microRNAs are discussed in their putative role in the pathogenesis of endometriosis.

Endometriosis with an aberrant immunophenotype: Challenging differential diagnosis of glandular lesions in the pelvic lymph nodes

CASE REPORT

We describe an unusual case of pelvic lymph node endometriosis with an aberrant immunophenotype mimicking metastasis of adenocarcinoma. A 37-year-old patient with a history of invasive cervical adenocarcinoma stage pT1a2 is presented. Due to insufficient loop electrosurgical excision procedure (LEEP) conization, total laparoscopic hysterectomy with pelvic lymphadenectomy was indicated. Intraoperatively, the diagnosis of deep infiltrating endometriosis of parametrial ligament and vesicouterine pouch, endometrioma of the left ovary and Allen Master's syndrome was suspected; the patient had no history or clinical symptoms of endometriosis. A PubMed search of similar cases was followed by a comparison to this case and discussion of the differential diagnosis of glandular lesions in the pelvic lymph nodes is reported.

RESULTS

Histological investigation showed no residual neoplasia; the diagnosis of endometriosis was confirmed. An interesting microscopic finding was represented by a solitary glandular lesion in one pelvic lymph node. Using immunohistochemistry, it was demonstrated that there was a complete loss of oestrogen and progesterone receptor expression (unlike parametrial ligament endometriosis). The diagnosis of endometriosis was based on the presence of endometrial stroma; malignancy was excluded by bland cytomorphologic features and results of immunohistochemical examination.

CONCLUSIONS

This type of aberrant of the endometriotic gland immunophenotype has never been presented in the scientific literature before. This finding plays a significant role from the pathology standpoint and, perhaps more importantly, from the clinical standpoint. An asymptomatic patient with a correct diagnosis of lymph node endometriosis did not undergo excessive treatment for false positive diagnosis of metastatic cervical adenocarcinoma.

Characteristics of histologically confirmed endometriosis in cynomolgus monkeys

STUDY QUESTION

What are the characteristics of spontaneous endometriosis in cynomolgus monkeys?

SUMMARY ANSWER

Spontaneous endometriosis in cynomolgus monkeys exhibited similar characteristics to the human disease.

WHAT IS KNOWN ALREADY

One previous report described the prevalence and the basic histopathology of spontaneous endometriosis in cynomolgus monkeys.

STUDY DESIGN, SIZE, DURATION

Endometriotic lesions that had been histologically confirmed in 8 female cynomolgus monkeys between 5 and 21 years old were subjected to study.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The monkeys died of, or were sacrificed because of, sickness consequent on endometriosis. Specimens were evaluated histopathologically with haematoxylin and eosin staining, iron staining and immunohistochemistry (CD10, CD31, α-SMA and PGP9.5), and by observing them under a microscope.

MAIN RESULTS AND THE ROLE OF CHANCE

Endometriotic and stromal cells (CD10-positive) with haemorrhage and inflammation were observed. Smooth muscle metaplasia and nerve fibres were also noted in the endometriotic lesions. Endometriotic lesions in lymph nodes were incidentally found.

LIMITATIONS AND REASONS FOR CAUTION

Since laparoscopic analysis for monitoring the disease state was not set as a parameter of the current study, time course changes (progression) of the disease were not assessed.

WIDER IMPLICATIONS OF THE FINDINGS

Further investigation of spontaneous endometriosis in cynomolgus monkeys may contribute to better understanding of the disease pathobiology.

STUDY FUNDING/COMPETING INTEREST(S)

No external funds were used for this study. A.N.K., S.M., S.H., T.I., O.K., A.K. and M.S. are full-time employees of Chugai Pharmaceutical Co., Ltd. R.K. received lecture fees from Chugai Pharmaceutical Co., Ltd., unrelated to the submitted work. S.N., S. O., L.Y., K.Y. and T.S. have nothing to declare.

TRIAL REGISTRATION NUMBER

N/A.

Immunohistochemical Investigation of Metastasis-Related Chemokines in Deep-Infiltrating Endometriosis and Compromised Pelvic Sentinel Lymph Nodes

Endometriosis is a prevalent benign disease, despite sharing several similarities with malignancies, such as the possibility of lymphatic spread. In malignancies, chemokines play a sovereign role in the process of metastasis. Metastasis-related chemokine axes have not yet been assessed in deep-infiltrating endometriosis (DIE), and this investigation was the aim of our study. The expression of these chemokines was investigated by immunohistochemistry in rectovaginal DIE lesions and in matched pelvic sentinel lymph nodes (PSLNs) of patients with endometriosis (n = 27), and their expression in the eutopic endometrium (EE) of endometriosis-free women (n = 20) was used as controls. Their staining pattern in rectovaginal DIE, in endometriotic lesions affecting the PSLN as well as in the EE of patients without endometriosis was characterized for the first time. Overall, these chemokines were highly expressed in DIE and endometriosis in PSLN. Chemokines might be involved in the spread of endometriosis and should be further investigated.

18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography-Positive Lymph Node Endometriosis Masquerading as Lymph Node Metastasis of a Malignant Tumor

Endometriosis is defined as the presence of endometrium-like tissues at extrauterine sites, most commonly in the abdominal cavity. Lymph node endometriosis is a rare but clinically important type of endometriosis that can mimic lymph node metastasis of a malignant tumor.18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) is a useful tool for diagnosing malignant tumors, although it occasionally shows false positive results in tissues with high metabolic activity caused by severe inflammation. In the present report, we describe a case of lymph node endometriosis that mimicked lymph node metastasis of a malignant tumor and showed a positive result on18F-FDG PET/CT. The findings of the present case suggest that lymph node endometriosis could present as swollen lymph nodes with18F-FDG PET/CT-positive results and provide important information for determining an appropriate treatment strategy.

The endometrial lymphatic vasculature: function and dysfunction

The endometrium has a complex and dynamic blood and lymphatic vasculature which undergoes regular cycles of growth and breakdown. While we now have a detailed picture of the endometrial blood vasculature, our understanding of the lymphatic vasculature in the endometrium is limited. Recent studies have illustrated that the endometrium contains a population of lymphatic vessels with restricted distribution in the functional layer relative to the basal layer. The mechanisms responsible for this restricted distribution and the consequences for endometrial function are not known. This review will summarise our current understanding of endometrial lymphatics, including the mechanisms regulating their growth and function. The potential contribution of lymphatic vessels and lymphangiogenic growth factors to various endometrial disorders will be discussed.

Deep endometriosis: definition, diagnosis, and treatment

Deep endometriosis, defined as adenomyosis externa, mostly presents as a single nodule, larger than 1 cm in diameter, in the vesicouterine fold or close to the lower 20 cm of the bowel. When diagnosed, most nodules are no longer progressive. In >95% of cases, deep endometriosis is associated with very severe pain (in >95%) and is probably a cofactor in infertility. Its prevalence is estimated to be 1% -2%. Deep endometriosis is suspected clinically and can be confirmed by ultrasonography or magnetic resonance imaging. Contrast enema is useful to evaluate the degree of sigmoid occlusion. Surgery requires expertise to identify smaller nodules in the bowel wall, and difficulty increases with the size of the nodules. Excision is feasible in over 90% of cases often requiring suture of the bowel muscularis or full-thickness defects. Segmental bowel resections are rarely needed except for sigmoid nodules. Deep endometriosis often involves the ureter causing hydronephrosis in some 5% of cases. The latter is associated with 18% ureteral lesions. Deep endometriosis surgery is associated with late complications such as late bowel and ureteral perforations, and recto-vaginal and uretero-vaginal fistulas. Although rare, these complications require expertise in follow-up and laparoscopic management. Pain relief after surgery is excellent and some 50% of women will conceive spontaneously, despite often severe adhesions after surgery. Recurrence of deep endometriosis is rare. In conclusion, defined as adenomyosis externa, deep endometriosis is a rarely a progressive and recurrent disease. The treatment of choice is surgical excision, while bowel resection should be avoided, except for the sigmoid.