An Immunodeficient Patient with Adenomyosis of the Uterus Complicated by Polyp-Like Endometriosis: A Case Report and Review of the Literature

A 44-year-old woman with a history of one cesarean section presented to our hospital with lower abdominal pain for 12 days. The patient reported irregular menstruation for the past year, sometimes even drenching vaginal bleeding for up to one month, and had been treated with oral progesterone, with unsatisfactory results. After admission, AFP, CEA, CA724, CA199 and HE4 were all found to be within the normal range, and only CA125 was found to be mildly elevated (161U/mL, normal:0–47U/mL). Because the patient was considered to have a malignant tumor by B-mode ultrasound before admission, a review showed that the uterus was about 6.7×5.8×5.7 cm in size, and the posterior wall of the uterus had rough and heterogeneous echogenicity of the myometrium in the localized area, with an area of about 3.9×2.8×2.8 cm. The left ovary was not clearly visible, a hypoechoic mass with a size of about 7.1×6.5×3.5 cm was detected in the left posterior part of the uterus. It had clear boundaries and heterogeneous internal echogenicity, and multiple cystic dark areas of unequal size could be seen in the mass. There were several cystic dark areas of different sizes with spongy changes, the larger one was about 3.0×1.2×1.1 cm, and the mass was not clearly demarcated from the left posterior myometrium, CDFI: abundant blood flow signal was detected in the mass ( Figure 1A and B ). Enhanced CT of the whole abdomen showed that the uterus was enlarged in size and irregular in shape, with scattered small flaky low-density foci in the uterine wall, obvious thickening of the posterior wall and flaky low-density foci, with unclear borders, and inhomogeneous enhancement on enhanced scanning; a cystic-solid mixed low-density foci could be seen in the left posterior part of the uterus, with unclear borders, with the largest cross-section of about 6.4×3.1 cm, and inhomogeneous enhancement on enhanced scanning, and a fine reticulation of the inner part of the lesion could be seen. There is uneven enhancement on enhancement scan, and fine reticulation can be seen in the internal part of the foci ( Figure 1C–F ). With the patient’s informed consent, we performed an exploratory laparoscopy. During this procedure, we found an enlarged spherical uterus measuring approximately 6×5×5 cm, a reddish mass on the left posterior wall with a soft texture. The mass had a diameter of approximately 6 cm at the contact surface with the uterine plasma layer and was adhered to the left ovary ( Figure 2A ). In addition, smaller similar tissues were found attached to the right posterior wall of the uterine fundus ( Figure 2B ), During the removal of the mass, a large amount of suspected endometrial-like tissue is seen flowing out of the mass ( Figure 2C ). Rapid frozen pathology was sent for examination during the operation, which revealed that the endometrial tissue was in the proliferative stage. Since the patient had no reproductive requirements and strongly requested for removal of the uterus, the uterus and bilateral fallopian tubes were removed laparoscopically, and after removal from the vagina and dissection, a large amount of endometrial tissue remained in the uterine cavity ( Figure 2D and E ), and on dissection of the mass in the left posterior wall, the mass had an unclear border with the myometrium, and no obvious sinus tract was seen. ( Figure 2F ). The surgical procedure was uneventful, postoperative pathology and immunohistochemistry showed: (left posterior uterine wall mass) polyp-like endometriosis, focal mesenchyme with smooth muscle metaplasia, total volume 7*4*1cm, (uterus + both fallopian tubes) uterine adenomyosis, proliferative stage-like endometrium, localized simple hyperplasia. Immunohistochemistry: PAX8 (+), PAX2 (+), PTEN (+, no deletion seen), B-Catenin (+, cytomembrane), P54 (+, wild-type expression), Ki-67 (+, 10%), ER (++++, 90%). ( Figure 2G and H ). This patient was reviewed six months after the operation, and the abdominal pain and other symptoms had completely subsided, and CA125 had dropped to the normal range. There was no abnormality in the ultrasound examination. Figure 1 ( A ) Transvaginal ultrasound examination. ( B ) Transvaginal ultrasound examination. ( C ) Abdominal enhanced CT, arterial phase. ( D ) Abdominal enhanced CT, arterial phase. ( E ) Abdominal enhanced CT, venous phase. ( F ) Abdominal enhanced CT, venous phase. Figure 2 ( A ) Endometrioid tissue on the surface of the left ovary. ( B ) Endometrioid tissue on the serosal surface of the right uterus. ( C ) Suspected endometrial tissue is flowing out from the serosal surface of the uterus. ( D ) A frontal view of the uterus and bilateral fallopian tubes. ( E ) Sectional views of the uterus and bilateral fallopian tubes. ( F ) A cesarean section revealed a large amount of endometrial tissue in the uterine cavity. ( G ) Postoperative routine pathology, in which obvious endometrial interstitium and glandular tissue can be seen. ( H ) Postoperative routine pathology, in which obvious endometrial interstitium and glandular tissue can be seen. ( A ) Transvaginal ultrasound examination. ( B ) Transvaginal ultrasound examination. ( C ) Abdominal enhanced CT, arterial phase. ( D ) Abdominal enhanced CT, arterial phase. ( E ) Abdominal enhanced CT, venous phase. ( F ) Abdominal enhanced CT, venous phase. ( A ) Endometrioid tissue on the surface of the left ovary. ( B ) Endometrioid tissue on the serosal surface of the right uterus. ( C ) Suspected endometrial tissue is flowing out from the serosal surface of the uterus. ( D ) A frontal view of the uterus and bilateral fallopian tubes. ( E ) Sectional views of the uterus and bilateral fallopian tubes. ( F ) A cesarean section revealed a large amount of endometrial tissue in the uterine cavity. ( G ) Postoperative routine pathology, in which obvious endometrial interstitium and glandular tissue can be seen. ( H ) Postoperative routine pathology, in which obvious endometrial interstitium and glandular tissue can be seen. Of note, the patient had suffered from dermatomyositis for 5 years and was currently taking oral Methylprednisolone (2 mg, po, qd) and Mycophenolate Mofetil Tablets (1.75 g, po, qd). The patient’s antimyositis antibody profile and IgM+IgG+IgA were all at normal levels after admission to the hospital, suggesting that the dermatomyositis was under control in a stable state.

Among all types of endometriosis, polypoid endometriosis occurs in less than 1% of cases, and most confirmed diagnoses rely on postoperative pathological examination, suggesting that its true incidence may be further underestimated. Due to its clinical manifestations resembling malignant tumors, this condition is often misdiagnosed as malignant lesions preoperatively, leading to excessive radical surgeries in most patients—a situation that imposes higher demands on gynecologists, radiologists, and pathologists. In clinical practice, it is essential to: conduct thorough preoperative evaluation, minimize unnecessary procedures during surgery while ensuring complete lesion removal, reduce surgical trauma as much as possible, and guide long-term postoperative treatment through accurate pathological diagnosis. The diffuse nature of adenomyosis lesions within the myometrium, combined with the polypoid growth pattern of endometriosis, increases the difficulty of preoperative accurate diagnosis and may even complicate surgical procedures. Current research suggests that some cases of endometriosis exhibit significant progesterone resistance, leading to suboptimal responses to hormonal therapy in patients with concurrent adenomyosis and polypoid endometriosis. Furthermore, excessive estrogen expression may accelerate disease progression. Relevant studies indicate that some patients with endometriosis are more prone to developing multiple autoimmune diseases, and there is a certain genetic correlation between the two. Under normal circumstances, abnormal endometrial tissue that enters the abdominal cavity should be rapidly cleared by the immune system. However, in immunocompromised patients, decreased activity of NK cells or abnormal function of macrophages can weaken the body’s ability to eliminate abnormal endometrial tissue. Additionally, elevated levels of inflammatory factors in the body further promote the formation of chronic inflammation in endometriosis, facilitate microvascular angiogenesis at the lesion site, thereby exacerbating pain symptoms and tissue fibrosis, leading to disease progression.

The coexistence of polypoid endometriosis and adenomyosis represents a notable diagnostic pitfall. Both conditions share similar clinical symptoms, including dysmenorrhea, abnormal uterine bleeding, and uterine enlargement, which often leads to an initial diagnosis of adenomyosis alone. Radiologically, polypoid endometriosis frequently appears as a solid or mixed mass with strong enhancement, mimicking gynecologic malignancies. The presence of adenomyosis further obscures lesion origin and complicates preoperative assessment. Intraoperative findings may also resemble malignant disease, potentially leading to overtreatment. Histologically, the complex glandular architecture and stromal fibrosis of polypoid endometriosis, particularly within an adenomyosis background, can mimic low-grade malignancies, while no specific biomarkers are available for differentiation. Therefore, careful clinicopathologic correlation is essential to avoid misdiagnosis and inappropriate management. In conclusion, we report a rare case of pelvic polyp-like endometriosis combined with adenomyosis, and elaborate on the current advances in the diagnosis and treatment of polyp-like endometriosis, and finally analyze its possible potential association with autoimmune diseases. It provides a new sample for future related research.

Endometriotic diseases mainly include endometriosis and adenomyosis. When endometrial tissue (glands and stroma) appears outside the uterine, it is called endometriosis(EM). EM can be divided into ovarian EM, peritoneal EM and deep infiltrating EM. 1 In addition, endometriosis can also be found in specific areas such as the lungs, vagina, urethra, and kidneys. The exact cause of endometriosis remains unclear, and the widely accepted theory is the reverse menstrual flow doctrine. However, this doctrine cannot explain endometriosis in patients with congenital absence of uterus. The theory of somatic epithelial chemotaxis and the theory of induction have also been widely discussed. 2 Tissues with the ability to proliferate and differentiate, such as the greater omentum or the pelvic peritoneum, cannot be excluded from the possibility of differentiation toward Müllerian cells under the influence of certain factors. According to statistics, the probability of patients with adenomyosis having other types of endometriosis at the same time is 33.6–40.4%. 3 Adenomyosis and endometriosis not only share similar clinical manifestations, including dysmenorrhea, infertility and chronic pelvic pain. Endometriosis and adenomyosis are sister entities with similar molecular mechanisms. 4 Activating mutations in KRAS are the most common genetic variant in endometriotic epithelial cells, whereas adenomyotic epithelial cells almost exclusively carry KRAS mutations. 5 However, compared to their similarities, there are still significant differences between the two diseases, including different prevalence rates and pathophysiology. We retrieved a total of 33 publications on polyp-like endometriosis from PUBMED from 2003–2023. Polyp-like endometriosis is a rare form of endometriosis that has now been found to grow in the ovary, 6 bowel, 7 uterine plasma membrane, mucosa of cervicall 8 or vagina, 9 , 10 ureters, 11 fallopian tubes, greater omentum, 12 bladder, 13 retroperitoneum, 14 pouch of Douglas, 15 even places like the kidneys. 16 Some studies have shown that polyp-like endometriosis is more common in postmenopausal women than in premenopausal patients, with a probability of about 60%. 17 This may be related to a previous history of SERM application (especially tamoxifen). 18–20 The patient had taken progesterone, so the patient’s polypoid endometriosis growth may be caused by the rapid growth of the lesion after stopping the drug. 21 , 22 More specific causes remain to be explored. Polyp-like endometriosis is similar to malignant tumors on imaging, and on B-mode ultrasound, polyp-like endometriosis appears as an irregular solid echogenic mass with internal vascularization and tends to invade the periphery (cross-referenced 4). Differential significance of CT and PET-CT is not significant, 23 MRI, especially DWI, may be useful in the evaluation of disease, 24 , 25 T2-WI shows high intensity slightly below the endometrium and surrounded by a peripheral low-intensity rim, 26 , 27 which may be related to fibrosis around the lesion. 28 In morphologically, it also mimics the growth pattern of malignant tumors, such as unrestricted invasive growth into surrounding tissues 29 , 30 and nerve, lymphatic, and vascular involvement (cross-referenced 2,3). It is therefore easily mistaken for a malignant tumor originating from the cervix or ovaries. However, under the microscope, the lesion consists of endometrial glands whose component was positive for oestrogen receptor and progesterone receptor and mesenchyme. The polyp-like growth into the cavity can be seen at the same time bleeding, fibrosis, thick-walled blood vessel formation and other typical manifestations of endometriosis, and does not have atypical hyperplasia, nuclear anomalies and active mitosis and other malignant tumor-like changes. 31 Immunohistochemistry also shows strong estrogen or progesterone receptor expression in the lesion, with increased P16 expression (cross-referenced 6) and absence of interstitial CD73 expression, 32 which suggests that increased local estrogen synthesis as well as abnormal mesenchymal proliferation may be direct or indirect factors in the development of polyp-like endometriosis. 33 Possibly KI-67 index and P53 negativity can be differentiated from malignant tumors. For the treatment of polypoid endometriosis, due to its malignancy-like imaging presentation, the majority of case reports are surgical, with removal of the primary lesion followed by pathologic diagnosis, and long-term management after diagnosis is either low-dose estrogen in combination with progesterone (cross-referenced 5) or GnRH-a. 34 However, long-term follow-up after bilateral salpingo-oophorectomy is a possible management modality for a small number of patients whose lesions are too widely distributed to be completely removed surgically and who are refractory to pharmacologic therapy. 35 , 36 Polyps look like endometriosis with a low chance of malignancy, but most cases of malignancy are sarcomas. 37 The exact mechanisms involved remain unclear. Another noteworthy highlight is that the patient in this case developed dermatomyositis for 5 years and is now taking oral methylprednisolone (2 mg, po, qd) and morphenol ester dispersible tablets (1.75 g, po, qd), and we believe that the mechanism of endometriosis development is inextricably linked to this individual’s autoimmune disease (AD). This idea that has also been in 2 systematic reviews from the years 2019 and 2024 confirmed by studies showing that EM is thought to be associated with a range of autoimmune diseases, including systemic lupus erythematosus (SLE), Sjögren’s syndrome (SS), rheumatoid arthritis (RA), autoimmune thyroid disorder(ATD), coeliac disease (CLD), multiple sclerosis (MS), inflammatory bowel disease (IBD) and Addison’s disease. 38 , 39 However, we were unable to determine the sequence of development and presentation between EM and autoimmune diseases. So we searched PUBMED for 20 recent publications from 2019–2025 with the keywords “endometriosis” and “autoimmune disease” to further explore the link between endometriosis and autoimmune disease. Autoimmune disease is a collective term for a group of different conditions characterized by abnormalities in the reactivity of B and T cells to normal components of the host and resulting in higher levels of inflammation in the individual. 40 That is, the inflammatory microenvironment is a very important part of the mechanism of EM-associated ID and may even share a common background in genetics. 41–43 The possible reasons for this are: 1. Retrograde menstruation in EM patients leads to a pelvic inflammatory environment where most women with normal immune function can clear ectopic endothelial lining, whereas abnormal immune function is insufficient for ectopic endothelial lining clearance, which leads to the occurrence of EM 44 and the development of related infertility. 45 This reason applies to both adult and adolescent women; 46 2. Patients with EM contain abnormalities of virtually all types of immune cells, including elevated levels of peritoneal neutrophils and macrophages, decreased cytotoxicity of natural killer cells, and abnormal numbers of T and B lymphocytes that contribute to the growth, maintenance, invasion, and angiogenesis of endometriotic cells, 47 This further leads to overexpression of associated serum autoantibodies. 48 , 49 This may also be one of the reasons why EM patients are more likely to develop new forms of AD like RS, 50 immune thrombocytopenia (ITP), 51 SS 52 and related infertility. 53 Based on these two main reasons, some scholars have suggested that EM patients with concomitant AD portend more severe disease progression. 54 Some scholars have also conceptualized novel targeted therapies targeting autoantibodies. 55–57 Although there is still a long way to go before clinical practice, an in-depth study of the relationship between EM and AD is of crucial importance for the co-diagnosis and co-treatment of several diseases. 58