Endometriosis Stones in Ovary: A Case Report

Endometriosis, Stone, Case report, Adnexal tumor Received: 2025/01/05 Accepted: 2025/04/26 Published Online: 18 Jul. 2026 Corresponding Information: Maral Hosseinzadeh, Department of Obstetrics and Gynecology, Shahid Beheshti University of Medical Sciences, Tehran, Iran Email: [email protected] Copyright © 2026, This is an original open-access article distributed under the terms of the Creative Commons Attribution-noncommercial 4.0 International License which permits copy and redistribution of the material just in noncommercial usages with proper citation . 1. Introduction Bone formation and calcifications in the ovaries are typically associated with mature teratomas and are rarely observed in other circumstances (1). Several uncommon causes of bone formation and calcification in the ovary have been reported, including endometriotic cysts, cystadenocarcinoma, primary or metastatic carcinoma, fibromas, and leiomyomas; however, these have been described only in a few cases. This condition has been associated with some cases of infertility, but it remains uncommon (2). There have also been reports of bone formation in the ovary without any apparent cause. This may result from heterotopia or metaplasia of the ovarian connective tissue (3,4). Only a few cases of ovarian bone formation secondary to endometriosis have been reported in the medical literature (5). In this case report, we describe a woman with significant ossification and calcification of the ovarian stroma associated with small areas of endometriosis in her ovary. 2. Case Presentation A 42 -year-old Iranian woman (gravida 3, para 3) presented to the gynecology clinic with a 1‑month history of lower abdominal pain. The pain was colicky and was not associated with fever, abdominal discomfort, nausea, or vomiting. She denied a history of weight loss, difficulty with micturition, heavy menstrual bleeding, anorexia, dyspnea, or dyspareunia. She had a regular menstrual history with normal menstrual flow. No significant personal or famil y history was reported. On initial physical examination, she had normal vital signs. A tender mass on the left side of the adnexa was detected during abdominal palpation, with no other abnormal findings. Pregnancy was excluded. Blood examination results, including complete blood count, C-reactive protein, hormone profile, and tumor markers, were all within reference ranges. Laboratory analysis showed that Cancer Antigen 125 (CA -125), Cancer Antigen 19 -9 (CA 19 -9), Carcinoembryonic Antigen (CEA), the hormone profile, and C -reactive protein were within normal limits. Transvaginal ultrasonography revealed a complex cystic lesion measuring 29 mm×32 mm with solid components in the left ovary, raising concern for malignant ovarian cancer. Magnetic resonance imaging of the abdomen and pelvis revealed a midline pelvic mass measuring 37×24 mm in the left ovary with thick septations. It contained nonhomogeneous solid components and an extensively calcified shell. 895 Endometriosis Stones in Ovary Volume 11, September 2026 Journal of Obstetrics, Gynecology and Cancer Research The patient was scheduled for elective oophorectomy. During surgical exploration, an enlarged, ovoid, pale ovary with foci of endometriosis was identified (Figure 1). The left ovary was carefully dissected to preserve tubal integrity. On bisection, the ovary revealed soft, dark brown material with extensive calcification. Two well -defined, stony fragments of dense tissue were noted within the endometrioma. Surgical pathological examination of the specimen showed the presence of an ovarian cyst and a portion of the fallopian tube. The ovarian cyst measured 4 cm in diameter and was associated with a segment of the fallopian tube measuring 3 cm in length. The thickness of the cyst wall ranged from 3 mm to 8 mm. Two stone fragments measuring 6 mm×5 mm×2 mm and 5 mm×4 mm×2 mm were identified. Histologically, the lesion was consistent with an endometrioma. Endometrial glands and stroma were present throughout the c yst wall, and hemosiderin deposits were noted. Immunohistochemical studies were negative for cytokeratins, CA -125, and WT1. There was no evidence of malignant transformation in the tissue, and all findings suggested a benign lesion. The patient was discharged a few days after surgery without complications. At the 6‑month follow‑up, she reported complete resolution of symptoms. Figure 1. Enlarged, ovoid, pale ovary with foci of endometriosis 3. Discussion In this article, we report a case of an ovarian cyst that underwent calcification and ossification in the presence of endometriosis. Endometriosis is a condition characterized by the presence of endometrial tissue outside the uterus, leading to various sym ptoms, including pain. In this case, the ovarian cyst had become firm and calcified within the surrounding tissue. This finding may have important implications for the management and treatment of the cyst. It is important to note that calcified adnexal masses may raise suspicion for ovarian tumors and often require surgical intervention. In cases where imaging studies suggest malignancy but blood tumor markers are normal, immunohistochemical studies can help differentiate between benign and malignant lesions. Immunohistochemistry involves the use of specific antibodies to detect particular proteins in tissue samples. This technique can help identify markers associated with malignant tumors, such as cytokeratins, CA-125, and WT1. However, it is important to note that the absence of these markers does not necessarily exclude the possibility of malignancy. Conservative management may be considered in cases of focal calcification in otherwise ultrasonographically normal ovaries. However, surgical intervention remains the treatment of choice for adnexal masses with extensive calcification. In our patient, surgical intervention was chosen because of recurrent episodes of abdominal pain. Nevertheless, the likely benign nature of an extensively calcified adnexal mass should be considered when planning surgical management. Heterotopic bone, or the presence of bone tissue in abnormal locations such as the ovary, has been linked to extensive endometriosis. Researchers have suggested that osseous metaplasia the transformation of one type of tissue into bone may occur as a response to the ongoing inflammatory damage caused by endometriosis. Campo et al., provided additional evidence supporting the inflammatory theory by reporting a case of osseous metaplasia in a patient with an Intrauterine Device (IUD) present in both the uterus and the ovaries. Several reported cases of ossification have also occurred in association with ovarian neoplasms, including luteinized thecomas, Sertoli -Leydig tumors, mucinous cystadenomas, and fibromas. These neoplasms have been found to contain calcified structures described as bony or bone‑like in appearance. In ovarian neoplasms, ossification may be related to the production of calcified material by tumor cells or to the presence of bone‑forming cells within the tumor tissue. In addition to these cases, ossification has also been reported without any associated abnormalities. Rosa e Silva et al., and Shipton et al., both published studies describing this phenomenon in detail. 4. Conclusion Ossification in the ovary is rare, and its pathogenesis remains unclear. Surgical intervention remains the primary treatment for ossified adnexal masses; however, the likely benign nature of such masses should be carefully considered. Further research is Maral Hosseinzadeh, et al. 896 Volume 11, September 2026 Journal of Obstetrics, Gynecology and Cancer Research needed to better understand the pathogenesis of ovarian ossification and to develop more effective management strategies. 5. Declarations Acknowledgments The authors would like to thank the patient and her family. Ethical Considerations formed written consent was obtained from the patient for the publication of this case report and any accompanying images. The patient’s anonymity was strictly maintained by removing all personal identifiers. Authors' Contributions P.Taherzadeh :Diagnosis, and writing original draft, M. Nemati: Writing, review and editing, M.Hosseinzadeh: Supervision. All authors approved the final manuscript and take responsibility for the integrity of the data. Conflict of Interest The authors declare no conflict of interest. Fund or Financial Support The authors declared no fund. 1. Zahn CM, Kendall BS. Heterotopic bone in the ovary associated with a mucinous cystadenoma. Mil Med. 2001;166(10):915 -7. [doi:10.1093/milmed/166.10.915] 2. Kramer HMC, Rhemrev JPT. Secondary infertility caused by the retention of fetal bones after an abortion: a case report. J Med Case Rep. 2008;:208. [doi:10.1186/1752-1947-2-208] 3. Eva A, Shipton S, Devenish Meares. Heterotopic bone formation in the ovary. 1965;5(2):100-2. [ doi:10.1111/j.1479- 828X.1965.tb00298.x] 4. Ding DC, Yu MH, Liu JY. Autocalcification of the ovary. Int J Gynaecol Obstet. 2002;79(2):161-2. [ doi:10.1016/S0020- 7292(02)00229-1] 5. Shaco-Levy R, Lazer T, Piura B, Wiznitzer A. Ovarian ossification associated with endometriosis. Clin Exp Obstet Gynecol. 2007;34(2):113-4. [PMID:17629168]

How to Cite This Article: Hosseinzadeh M, Taherzadeh P, Nemati M. Endometriosis Stones in Ovary: A Case Report J Obstet Gynecol Cancer Res. 2026;11(9):894-896. Download citation: RIS | EndNote | Mendeley |BibTeX |