{"paper_id":"d54bacc5-71c8-499f-a78a-2ef333a3de3f","body_text":"Review began\n 02/25/2025 \nReview ended\n 03/05/2025 \nPublished\n 03/06/2025\n© Copyright \n2025\nMishra et al. This is an open access article\ndistributed under the terms of the Creative\nCommons Attribution License CC-BY 4.0.,\nwhich permits unrestricted use, distribution,\nand reproduction in any medium, provided\nthe original author and source are credited.\nDOI:\n 10.7759/cureus.80145\nGenetic Origin of Osseous Metaplasia of the\nEndometrium: A Case Series\nMona Mishra \n, \nNeetu Singh \n, \nRupita Kulshrestha \n1.\n Obstetrics and Gynecology, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, IND\nCorresponding author: \nRupita Kulshrestha, \nrupita.kulshrestha@gmail.com\nAbstract\nOsseous metaplasia of the endometrium is the presence of mature and immature bone tissue inside the\nendometrial cavity. We present a case series of three women who presented with various complaints of\nvaginal discharge and menstrual abnormalities. On hysteroscopy, bone fragments were extracted.\nHistopathological study of the bone tissue was supportive of osseous metaplasia. We performed a DNA\nanalysis of the bone and compared it to the maternal genotype. We found a complete match between the\npatient and bone genotype, thus supporting that the bone originates from the patient.\nCategories:\n Obstetrics/Gynecology\nKeywords:\n bone in the endometrium, endometrial polymerase chain reaction, endometrium, genetic analysis,\nosseous, osseous metaplasia\nIntroduction\nTrue osseous metaplasia is the presence of mature and immature bone tissue inside the endometrial cavity.\nIt most frequently occurs during the reproductive years, but it has been reported in post-menopausal\nwomen also \n[1]\n. Women present with infertility and a variety of symptoms like menometrorrhagia, vaginal\ndischarge, and dyspareunia. Osseous metaplasia of the endometrium is rare with an incidence of 3/10,000,\nand less than 100 cases have been reported until now \n[2]\n. The current literature is uncertain regarding the\ngenetic origin of osseous metaplasia. Various theories have been hypothesized regarding its etiology, but the\nmost common theory is the metaplastic transformation of endometrial stromal cells into osteoblasts \n[3]\n. It\nhas been falsely attributed to the retention of fetal bones inside the uterine cavity after a prior\nabortion. Contrary to the belief that it has fetal origin, osseous metaplasia is genetically of maternal origin.\nThis can be demonstrated by comparing the patient's short tandem repeats (STR) and STR of the bone tissue.\nWe present a case series of three cases, out of which in one case we performed DNA analysis of the bone and\ncompared it with the maternal genotype. The study revealed that the DNA profile of the bone sample\nshowed a 100% match with the maternal DNA profile, thus confirming that the bone sample is of maternal\norigin rather than fetal origin.\nCase Presentation\nCase 1\nA 35-year-old woman presented to the outpatient clinic with the complaint of irregular vaginal spotting\nassociated with vaginal discharge. She was P3L3A2 with a history of surgical abortion twice previously. Two\nyears back, she underwent a first-trimester surgical abortion. When she presented to us, there was no\nhistory of menstrual overdue, and the urine pregnancy test was negative. Her examination findings were\nunremarkable. Her 2D transvaginal ultrasound revealed multiple echogenic structures inside the\nendometrial cavity, the largest measuring 17.5 mm (Figure \n1\n).\n1\n1\n1\n \nOpen Access Case Report\nHow to cite this article\nMishra M, Singh N, Kulshrestha R (March 06, 2025) Genetic Origin of Osseous Metaplasia of the Endometrium: A Case Series. Cureus 17(3):\ne80145. \nDOI 10.7759/cureus.80145\n\nFIGURE\n 1: 2D transvaginal ultrasound reveals multiple echogenic\nstructures inside the endometrial cavity, the largest measuring 17.5 mm\n(white arrow).\nA diagnostic hysteroscopy revealed multiple bone-like structures inside the uterine cavity (Figure \n2\n and\nFigure \n3\n).\nFIGURE\n 2: On hysteroscopic view, multiple bone-like structures are\nseen inside the uterine cavity (white arrow).\n \n2025 Mishra et al. Cureus 17(3): e80145. DOI 10.7759/cureus.80145\n2\n of \n13\n\nFIGURE\n 3: A long bone structure is seen inside the uterine cavity on\nhysteroscopy (white arrow).\nWe removed the bone fragments with graspers inserted inside the operating channel of the rigid\nhysteroscope. The bone fragments were sent for histopathology and DNA analysis. Histopathology of the\nbone fragment was consistent with osseous metaplasia (Figure \n4\n).\n \n2025 Mishra et al. Cureus 17(3): e80145. DOI 10.7759/cureus.80145\n3\n of \n13\n\nFIGURE\n 4: Photomicrograph demonstrates predominantly calcified\ntissue and endometrial tissue ossification (4× magnification) on\nhematoxylin and eosin staining.\nThe patient's sample and the bone sample were sent for DNA analysis, to compare both the genotypes.\nProcedure for DNA collection, polymerase chain reaction (PCR)\namplification, and analysis\nDNA Collection\nBone marrow specimens were processed under highly sterile conditions to preserve nucleic acid integrity and\nprevent contamination. Samples were aliquoted into 1.5 mL microcentrifuge tubes and subjected to\nproteolytic digestion by adding 20 µL of Proteinase K, 200 µL of lysis buffer containing chaotropic agents,\n200 µL of phosphate-buffered saline (PBS) to maintain isotonicity, and 50 µL of sodium dodecyl sulfate (SDS)\nto enhance membrane disruption and protein denaturation. The samples were incubated at 56°C for one\nhour to facilitate the enzymatic degradation of proteins and then at 80°C to ensure complete tissue lysis and\nthe denaturation of residual proteins or enzymes.\nFollowing digestion, genomic DNA was precipitated by adding 200 µL of 100% ethanol to the lysate,\npromoting DNA binding to the silica-based membrane during subsequent column purification. The lysate\nwas passed through the silica column 3-4 times to maximize DNA adsorption, followed by sequential\nwashing steps to remove contaminants, including residual salts and degraded proteins. Finally, the purified\nDNA was eluted in 30 µL of AE buffer. DNA extraction was conducted using the QIAamp DNA Mini Kit\n(QIAGEN, Hilden, Germany), adhering to the manufacturer's protocols for optimal yield and purity.\nPCR Amplification\nQuantitative fluorescence polymerase chain reaction (QF-PCR) assays were established using the Devyser\nExtend v2 Kit (Årsta, Sweden), which includes primers for amplifying specific chromosome loci. The assays\nutilized fluorescently labeled primers targeting STR markers across chromosomes X, Y, 21, 18, and 13. STR\nmarkers, which exhibit polymorphic variations in the number of repeat units, were employed as genetic\nmarkers for DNA sequence identification and the verification of chromosomal dosage.\nExtracted DNA from the bone marrow was diluted to a working concentration of 20 ng/µL using Qubit\nfluorometry for quantification (Thermo Fisher Scientific, Waltham, Massachusetts, United States). For each\nsample, 5 µL of DNA was added to 20 µL of the master mix provided in the kit. PCR amplification was\nperformed in a final volume of 25 µL. The thermal cycling conditions included an initial denaturation at\n95°C for 15 minutes, followed by 27 cycles of denaturation at 94°C for 30 seconds, annealing at 58°C for one\n \n2025 Mishra et al. Cureus 17(3): e80145. DOI 10.7759/cureus.80145\n4\n of \n13\n\nminute and 30 seconds, and extension at 72°C for one minute and 30 seconds. A final extension step at 72°C\nfor 30 minutes was carried out, and the reaction was held at 4°C indefinitely.\nCapillary Electrophoresis\nPost-amplification, the PCR products were analyzed using capillary electrophoresis. A loading cocktail was\nprepared by mixing 2 µL of the size standard (e.g., 560 SIZER ORANGE) with 100 µL Hi-Di Formamide\n(Thermo Fisher Scientific, Waltham, Massachusetts, United States). From this mix, 15 µL was dispensed into\neach well of a microwell plate. Subsequently, 1.5 µL of each PCR product was added to the corresponding\nwells. The plate was sealed and loaded onto the ABI Genetic Analyzer (Applied Biosystems, Waltham,\nMassachusetts, United States) for separation.\nData Interpretation\nAnalysis of the fluorescence signals was conducted using GeneMapper v3.7 software (Applied Biosystems,\nWaltham, Massachusetts, United States). STR markers were identified and quantified by calculating the peak\narea ratios of alleles. Informative markers demonstrated heterozygosity with two distinct peaks of equal\nintensity, corresponding to alleles of different lengths. The peak area ratios were used to evaluate\nchromosomal dosage and detect potential aneuploidies. Results interpretation adhered to QF-PCR\nprinciples, accurately identifying chromosomal abnormalities based on the differential amplification of STR\nmarkers.\nResult of QF-PCR\nQF-PCR showed the same allele size detected in maternal peripheral blood and endometrial bone samples,\nsuggesting identical alleles. The analysis suggested shared genetic material, supporting the evidence of\nmaternal contribution to the endometrial tissue (Figure \n5\n).\n \n2025 Mishra et al. Cureus 17(3): e80145. DOI 10.7759/cureus.80145\n5\n of \n13\n\nFIGURE\n 5: QF-PCR shows the same allele size detected in the maternal\nperipheral blood and endometrial bone sample.\nQF-PCR: quantitative fluorescence polymerase chain reaction\nCase 2\nA 35-year-old nulliparous woman with primary infertility presented with secondary amenorrhea for two\nmonths. She had no previous history of cervical or intrauterine procedures. She had an episode of heavy\nmenstrual bleeding six months back. Apart from this episode, her past menstrual cycles were regular with\naverage flow. She was evaluated at a private healthcare facility, and an echogenic structure in her\nendometrial cavity was seen on transvaginal ultrasound. Suspecting a foreign body, the echogenic structure\nwas extracted under general anesthesia. Histopathology of the echogenic structure revealed stratified\nsquamous metaplasia with bone formation. Six months later when she presented to our facility with\nsecondary amenorrhea, her abdomen was soft and non-tender. On speculum examination, the cervix was\nunremarkable with vaginal discharge. Bimanual examination revealed a non-tender bulky uterus and free\nadnexa. Her 2D transvaginal ultrasound revealed a large intrauterine collection with homogenous internal\nechoes and echogenic foci in the endometrial cavity (Figure \n6\n). Echogenic heterogeneous dependent\ncontents were also noted in the collection.\n \n2025 Mishra et al. Cureus 17(3): e80145. DOI 10.7759/cureus.80145\n6\n of \n13\n\nFIGURE\n 6: 2D transvaginal ultrasound shows a large collection inside\nthe uterine cavity with homogenous internal echoes and echogenic foci\n(white arrow).\nMagnetic resonance imaging (MRI) showed a bulky uterus with well-defined T1 and T2/short tau inversion\nrecovery (STIR) hyperintense to intermediate signal intensity lesions in the lower uterine segment,\nendometrial cavity, and endocervical canal. Blooming was seen on gradient echo (GRE) images suggestive of\na hemorrhagic collection inside the uterine cavity. There was no evidence of diffuse restriction. Endocervical\nstroma and the endometrium appeared to maintain signal intensity (Figure \n7\n).\n \n2025 Mishra et al. Cureus 17(3): e80145. DOI 10.7759/cureus.80145\n7\n of \n13\n\nFIGURE\n 7: T2-weighted coronal MRI shows a hyperintense to\nintermediate signal intensity lesion in the lower uterine segment,\nendometrial cavity, and endocervical canal (black arrow). Evidence of\nhemorrhagic collection is seen inside the uterine cavity (white arrow).\nMRI: magnetic resonance imaging\nWe performed a diagnostic hysteroscopy on the patient. After progressive dilatation of the cervix, around\n100 ml of altered blood was evacuated from the uterine cavity. Hysteroscopy showed multiple trabecular\nbony fragments in the endometrial cavity (Figure \n8\n).\n \n2025 Mishra et al. Cureus 17(3): e80145. DOI 10.7759/cureus.80145\n8\n of \n13\n\nFIGURE\n 8: A hysteroscopic view of the bone fragment (white arrow) and\nthe synechiae (black arrow) in the uterine cavity.\nFragments were removed with graspers inserted in the operating channel of a rigid hysteroscope. Multiple\nsynechiae in the uterine cavity were seen which were lysed with scissors. A tissue biopsy of endometrial\ntissue was obtained and analyzed for histopathology, Ziehl-Neelsen (ZN) stain, and Mycobacteria Growth\nIndicator Tube (MGIT) culture. A size 8 pediatric catheter was inserted in the uterine cavity immediately\nafter hysteroscopy which was removed after 10 days. We gave oral estrogen treatment to prevent the\nreformation of adhesions postoperatively along with timed progestin therapy to induce withdrawal\nbleeding. Histopathological evaluation showed tissue comprising round-oval endometrial glands with tall\ncolumnar epithelium with minimal intervening stroma showing fibrosis with osseous metaplasia.\nHistological evaluation of the surrounding endometrium in our case showed evidence of mild inflammatory\ninfiltrate and intervening stromal fibrosis. No acid-fast bacilli were found in the endometrial tissue on the\nZN stain, and the MGIT culture was sterile.\nAfter the procedure, the patient started having regular menses. She was well, asymptomatic, and reviewed in\nthe preconception clinic to embark on pregnancy.\nCase 3\nA 27-year-old woman presented to the outpatient clinic with complaints of vaginal discharge. She also had\nirregular and heavy menstrual bleeding for one year. The complaints started following a dilatation and\ncurettage of a first-trimester spontaneous abortion. There were no complaints of immediate post-abortal\ncomplications. She has had two previous vaginal deliveries preceding the abortion six years and eight years\nback which were uneventful. Her previous cycles were regular, with average blood flow and no associated\ndysmenorrhea.\nOn examination, no significant finding was noted. On bimanual palpation, the uterus was of normal size and\nthe adnexa was free. She underwent a transvaginal ultrasound which revealed an irregular endometrium\nwith multiple echogenic foci, the largest measuring 15 mm (Figure \n9\n).\n \n2025 Mishra et al. Cureus 17(3): e80145. DOI 10.7759/cureus.80145\n9\n of \n13\n\nFIGURE\n 9: A hysteroscopic view of a trabecular bone fragment inside\nthe uterine cavity (white arrow).\nA diagnostic hysteroscopy was performed. It showed numerous bone fragments inside the endometrial\ncavity. A 1.5-cm-long bony spicule was extracted using graspers and sent for histopathological examination.\nThe histopathological findings were consistent with osseous metaplasia. The patient has subsequently\nresumed her normal menses and is symptom-free.\nDiscussion\nTwo main theories have been described in the literature to explain the etiopathogenesis of osseous\nmetaplasia of the endometrium: first is the retention of fetal bones secondary to previous abortions \n[4]\n and\nsecond is the metaplastic transformation of pluripotent stromal cells into osteoblasts secondary to chronic\ninflammation. In a nulliparous woman, the second hypothesis of metaplastic transformation is more\nobvious. However, in women with previous abortions, it is unclear if the bone formation occurs due to the\nmetaplastic transformation of one's tissue or due to retained fetal tissue. Tulandi et al. found bones of fetal\norigin inside the uterine cavity, as confirmed by genetic analysis \n[4]\n. However, in a study performed by\nCayuela et al., DNA analysis of the affected woman was compared to that of osseous tissue, and the genetic\norigin of both was identical \n[5]\n. Thus, the literature has conflicting evidence regarding the actual origin of\nthe bone tissue.\nIn our study, case 1 is relevant in this regard, as we performed QF-PCR to compare the genetic makeup of the\nbone with that of the patient. Even though she had previous abortions, the DNA sample of the bone and\npatient was a complete match. Another differential is dystrophic calcification, defined as calcium deposition\nin devitalized and necrotic tissue \n[6]\n. It has been known to occur in the musculoskeletal system secondary to\ninjury \n[6]\n. However, in this condition, there are no osteoblasts and the presence of purely calcium\ndeposition. In our cases, the presence of osteoblasts excluded this possibility. It is interesting to know that\nmetabolic disorders like hypervitaminosis D, hypercalcemia, and hyperphosphatemia are known to cause\nsoft tissue calcifications \n[3]\n. In our study, all three cases did not have such metabolic disorders.\nWomen with osseous metaplasia of the endometrium present with vague gynecological symptoms and\ninfertility. In a retrospective observational study, 63 women diagnosed with osseous metaplasia on\nhysteroscopy were included. It was found that dysmenorrhea, abnormal uterine bleeding, infertility, and at\nleast one miscarriage were present in 34.9%, 27%, 23.8%, and 65.1%, respectively \n[7]\n. Secondary infertility\nmay occur as the bone tissue causes local inflammation by the release of prostaglandins and has an\nintrauterine copper device (IUCD)-like effect. An interesting study found a reduction in menstrual flow and\nmenstrual blood prostaglandin levels after the extraction of osseous metaplasia \n[8]\n. In our study, women in\ncase 1 and case 3 presented with vaginal discharge and irregular vaginal bleeding (Table \n1\n).\n \n2025 Mishra et al. Cureus 17(3): e80145. DOI 10.7759/cureus.80145\n10\n of \n13\n\nCase\nParity\nPrevious\nabortions\nInfertility\nSymptoms\nImaging\nHysteroscopy\nfindings\nAdditional\ninvestigations\n1\nP3L3A2\nYes\nNo\nIrregular\nbleeding and\nvaginal\ndischarge\nTVS: multiple echogenic structures\ninside the endometrial cavity, the\nlargest measuring 17.5 mm\nMultiple bone-like\nstructures inside\nthe uterine cavity\nQF-PCR of the\nbone and\nmother\nshowed a\n100% DNA\nmatch\n2\nNulliparous\nNo\nYes\nSecondary\namenorrhea\nTVS: a large collection with\nhomogenous internal echoes and\nechogenic foci in the endometrial\ncavity. MRI showed a bulky uterus\nwith well-defined T1 and T2/STIR\nhyperintense to intermediate signal\nintensity lesions in the lower uterine\nsegment, endometrial cavity, and\nendocervical canal\n100 ml of\nhematometra\nevacuated.\nMultiple\nintrauterine\nsynechiae and\nmultiple trabecular\nbony fragments in\nthe endometrial\ncavity\nEndometrial\nbiopsy: ZN\nstain: no; AFB\nMGIT culture:\nsterile\n3\nP2L2A1\nYes\nNo\nMenstrual\nabnormalities\nand vaginal\ndischarge\nTVS: irregular endometrium with\nmultiple echogenic foci, the largest\nmeasuring 15 mm\n1.5-cm-long bony\nspicule\nNone\nTABLE\n 1: Summary of the clinical features of the three cases of osseous metaplasia.\nTVS: transvaginal ultrasound; QF-PCR: quantitative fluorescence polymerase chain reaction; HPE: histopathological examination; ZN: Ziehl-Neelsen; AFB:\nacid-fast bacilli; MGIT: Mycobacteria Growth Indicator Tube; MRI: magnetic resonance imaging; STIR: short tau inversion recovery\nBoth women had previous surgical abortions which is consistent with the current evidence regarding the\npresentation of women with osseous metaplasia \n[7]\n. The second case was unique as the woman presented\nwith secondary amenorrhea following a previous attempt at bone removal. On hysteroscopy, hematometra\nand intrauterine synechiae were found. The formation of hematomata secondary to osseous metaplasia was\nfirst reported in a patient who underwent a loop electrosurgical excision procedure (LEEP) for high-grade\ncervical intraepithelial neoplasia \n[9]\n. The author hypothesized that LEEP caused a local inflammatory state\nin the endometrium, promoting bone formation \n[9]\n. The pathophysiology behind osseous metaplasia is very\ninteresting and is the key to further explaining the possible cause of synechiae formation and adhesions.\nMany authors suggest that osseous metaplasia develops secondary to differentiating totipotent stromal cells\nlike fibroblasts into osteoblasts \n[3]\n. This change may be initiated by a chronic inflammatory cascade\nsecondary to local trauma, intrauterine infections, and cervical intraepithelial neoplasia \n[10]\n. Thus, chronic\ninflammation is the key event behind the metaplastic transformation of non-osseous to osseous tissue. It\nhas been stated that an interplay between various pro-inflammatory mediators mediates bone formation\nand resorption \n[11]\n. IL-12, IL-18, IL-33, and interferons (IFN) suppress osteoclastic differentiation and thus\ninhibit bone loss \n[11]\n. \nIn case 2, one of the following can be a possible pathophysiology and explanation behind bone formation\nand intrauterine adhesions. First, previous intrauterine infection might have caused a pro-inflammatory\nmilieu inside the uterine cavity promoting bone formation. Previous attempts to remove the bones could\nhave further accelerated the local injury, inflammation, and repair cycle leading to the formation of\nintrauterine adhesions. Second, the intrauterine bone fragments in the dependent part of the uterine cavity\nmight have caused mechanical obstruction leading to the formation of hematometra. Third, retained bones\nin the cavity might have undergone secondary infection leading to the release of inflammatory cytokines\nand adhesion formation. \nTransvaginal ultrasound is the first line of investigation to diagnose osseous metaplasia. The presence of\nechogenic foci with posterior acoustic shadowing is pathognomonic in this condition \n[11]\n. The coronal view\nof 3D ultrasound is useful in identifying irregular margins and differentiating them from other pathologies\nthat come to mind like a retained IUCD or a foreign body \n[12]\n. In case of a further diagnostic dilemma, MRI\ncan be used as an adjunct, in which other coexistent pathologies like hematometra and malignancies can\nalso be evaluated. In case 1 and case 3, we did a 2D ultrasound only, before proceeding for hysteroscopy.\nHowever, in case 2, fluid collection inside the uterine cavity and echogenic foci found on 2D ultrasound\nraised suspicion for a hematometra. Therefore, we opted for an MRI.\n \n2025 Mishra et al. Cureus 17(3): e80145. DOI 10.7759/cureus.80145\n11\n of \n13\n\nThe mainstay of management is the removal of the bone fragments under hysteroscopic view. This\ntechnique is useful for directly visualizing the tissue and ruling out other coexistent issues like intrauterine\nadhesions, endometritis, and malignancy. Hysteroscopy effectively relieves symptoms and leads to a return\nof fertility \n[8]\n.\nOur case series is unique as it is the third of its kind in this regard \n[4,5]\n. It highlights the maternal origin of\nosseous metaplasia by performing a genetic analysis. In addition, it sheds light on the fact that osseous\nmetaplasia may present with secondary amenorrhea and intrauterine synechiae, which is a unique\npresentation. However, our study is not without limitations. Firstly, we couldn't do genetic testing in all\nthree cases as the patient did not consent to the same due to financial constraints. Secondly, because of the\nlow number of cases, it is early to state the existing correlation between patient symptoms and osseous\nmetaplasia. Larger studies need to be performed to support these findings. Thirdly, the cause-effect\nrelationship between osseous metaplasia and intrauterine adhesions is doubtful, and further studies are\nnecessary to throw light in this direction. Further research is needed to understand the link between chronic\ninflammation and the development of osseous metaplasia. Other future research prospects include\ninvestigating new diagnostic tools like noninvasive biomarkers in blood or menstrual blood, which may help\nin the diagnosis and monitoring of such cases.\nConclusions\nOsseous metaplasia of the endometrium is a rare entity that may have a varied presentation. Its primary\ndifferential is the retention of fetal bones secondary to previous abortion. The genetic origin of bones in the\nuterine cavity can be confirmed by genetic testing. In our study, QF-PCR testing of the bone was done,\nsuggesting that it is genetically derived from the patient and not from the fetus.\nAdditional Information\nAuthor Contributions\nAll authors have reviewed the final version to be published and agreed to be accountable for all aspects of the\nwork.\nConcept and design:\n  \nMona Mishra, Neetu Singh\nAcquisition, analysis, or interpretation of data:\n  \nMona Mishra, Rupita Kulshrestha\nDrafting of the manuscript:\n  \nMona Mishra, Rupita Kulshrestha\nCritical review of the manuscript for important intellectual content:\n  \nMona Mishra, Neetu Singh\nDisclosures\nHuman subjects:\n Consent for treatment and open access publication was obtained or waived by all\nparticipants in this study. \nConflicts of interest:\n In compliance with the ICMJE uniform disclosure form, all\nauthors declare the following: \nPayment/services info:\n All authors have declared that no financial support\nwas received from any organization for the submitted work. \nFinancial relationships:\n All authors have\ndeclared that they have no financial relationships at present or within the previous three years with any\norganizations that might have an interest in the submitted work. \nOther relationships:\n All authors have\ndeclared that there are no other relationships or activities that could appear to have influenced the\nsubmitted work.\nReferences\n1\n. \nShimizu M, Nakayama M: \nEndometrial ossification in a postmenopausal woman\n. 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Eur J Clin Invest. 2011,\n41:1361-6. \n10.1111/j.1365-2362.2011.02545.x\n12\n. \nGrigore M, Pristavu A, Gafitanu D: \nUltrasound features of osseous metaplasia of the endometrium-case\nseries and review of the literature\n. Clin Imaging. 2018, 52:260-3. \n10.1016/j.clinimag.2018.08.006\n \n2025 Mishra et al. Cureus 17(3): e80145. DOI 10.7759/cureus.80145\n13\n of \n13","source_license":"CC0","license_restricted":false}