2026 年 13 巻 p. 433-437
Orbital metastasis from endometrial cancer is rare. In particular, metastasis to the extraocular muscles has not been reported. Herein, we present a case of endometrial metastasis to the extraocular muscles. A 70-year-old woman presented with a history of endometrial cancer, with complaints of pain, proptosis, and swelling in her left eyelid. Since magnetic resonance imaging revealed a left orbital tumor, she was referred to our hospital. The tumor was 25 mm in size and was located in the inferior medial extraocular muscle. As the tumor had ring enhancement, and the patient was undergoing treatment for endometrial cancer, orbital metastasis was suspected. We performed tumor resection and orbital decompression by endoscopic endonasal surgery. The pathology results revealed metastasis from the endometrial cancer. After the surgery, her symptoms improved, and stereotactic radiation therapy was initiated. Although, treatment resulted in the shrinkage of the orbital metastasis tumor, the primary tumor progressed, and she died 4 months after her initial visit to our department. The endoscopic endonasal approach to extraocular muscle metastasis was minimally invasive and was effective in reducing pain. In addition, radiotherapy showed a marked effect on the residual tumor, suggesting that combination of these treatments was beneficial.
Orbital tumors encompass a wide variety of pathological entities with differing degrees of malignancy and treatment strategies. Among them, orbital metastatic tumors have been reported to account for approximately 1-13% of orbital tumors in adults.1-4) The most common primary site of orbital metastases is the breast, followed by the lungs, prostate, and malignant melanoma.3,5)
Endometrial carcinoma is the sixth most commonly diagnosed cancer in females worldwide, and its incidence rate is rising due to aging populations and increasing prevalence of obesity.6) Orbital metastasis from endometrial carcinoma is rare, and to date there are no reports of it metastasizing to the extraocular muscles. Herein, we report a case with orbital metastasis from endometrial carcinoma that localized in the extraocular muscle, which was treated by endoscopic endonasal surgery and radiation.
The 70-year-old woman was diagnosed with stage IIIA endometrial carcinoma, and underwent a modified radical hysterectomy, bilateral salpingo-oophorectomy, omentectomy, and pelvic lymphadenectomy followed by adjuvant chemotherapy. Eighteen months after the surgery, she developed left eye pain, proptosis, and diplopia, which progressively worsened. Magnetic resonance imaging revealed a left orbital tumor; therefore, the patient was referred to our department (Figure. 1).
MRI of the left orbital metastatic tumor when the patient was diagnosed. The tumor was identified within the inferior rectus muscle (A, B). Images 2 weeks after diagnosis. On enhanced MRI, the lesion exhibited ring enhancement (C, D). The tumor demonstrated progressive enlargement on MRI 4 weeks after diagnosis (E, F). The arrow-heads indicate the inferior rectus muscle and the arrow indicates the tumor.
MRI; magnetic resonance imaging
On ophthalmological examination, the corrected visual acuity was found to be 1.2 in the right eye and 1.0 in the left eye. The pupils were normal, and no visual field defect was observed. Funduscopic examination revealed no arteriosclerotic changes, and the optic disc showed good color with sharp margins. Chori retinal folds were observed temporal to the macula. Diplopia due to impaired upward gaze of the left eye was also noted. Intraocular pressure was 13 mmHg in the right eye and was elevated to 24 mmHg in the left eye. The tumor was a 17-mm ring-enhancing lesion confined to the left inferior rectus muscle, which we considered was a metastatic tumor based on her history. After 2 weeks, the tumor had enlarged to 25 mm; we performed tumor resection via endoscopic endonasal surgery. The tumor was located in the inferior rectus muscle adjacent to the maxillary sinus, and a trans maxillary approach was considered capable of providing orbital inferior wall decompression in addition to facilitating tumor resection. Moreover, to improve maneuverability within the maxillary sinus, a modified medial maxillectomy approach was selected. The endoscope was introduced into the left nasal cavity, and the mucosa at the base of the inferior turbinate was incised and dissected from the medial wall of the maxillary sinus (Figure. 2). The medial wall of the maxillary sinus was drilled, and the mucosa was incised to gain access to the maxillary sinus. Tumor extension into the maxillary sinus was not observed. For a secure, sufficient working space for manipulation, the anterior wall of the maxillary sinus was drilled, and the ethmoid sinus was opened. The tumor location was identified using the neuro navigation system (StealthStation, Medtronic, Minnesota, USA), and the orbital floor was drilled. After incision of the periorbita, the tumor was identified. The boundary between the tumor and the surrounding normal tissue was well defined, allowing careful dissection along the tumor margins. Intraoperative pathology revealed metastasis from the endometrial cancer. The tumor was resected to the extent possible, and normal adipose tissue was identified posterior to the tumor. After resection, we did not perform reconstruction for decompression.
The surgical views. The endoscopic endonasal approach was used via the left nasal cavity, and the base of the inferior turbinate was incised (A). The medial wall of the maxillary sinus was drilled to access the maxillary sinus (B). An endoscope was inserted into the maxillary sinus to inspect the interior, and the orbital floor and infraorbital nerve were identified (C). The inferior orbital wall was drilled to achieve adequate decompression. After incision of the periorbita, the tumor was identified (D). The tumor was dissected from the surrounding normal tissue, and resection was achieved (E). Postoperative images following tumor resection. No rigid reconstruction was performed to preserve orbital decompression (F). The asterisk indicates the infraorbital wall; the number sign indicates the infraorbital nerve; arrows indicate the tumor; and the arrowhead indicates orbital fat.
After the surgery, her eye pain improved. On ophthalmological examination performed after the surgery, visual acuity, visual fields, funduscopic findings, and ocular motility disturbance remain unchanged, while intraocular pressure decreased to within the normal range (11 mmHg in the right eye and 16 mmHg in the left eye). She was discharged 7 days after surgery, and the pathological analysis revealed metastasis from endometrial carcinoma; therefore, we performed stereotactic radiotherapy (35 Gy/14 fr). Although the orbital tumor showed no progression during follow-up, the primary cancer advanced, and the patient was transitioned to palliative care (Figure. 3). She died 4 months after her initial visit to our department.
Postoperative images. MRI after the operation (A). CT before SRT, the left orbital inferior wall was removed, achieving orbital decompression (B, C). CT after SRT, the tumor demonstrated shrinkage (D).
CT: computed tomography; MRI: magnetic resonance imaging; SRT: stereotactic radiation therapy
Informed consent for publication of the case report was obtained from the patient and her family. This study was approved by the Ethics Committees of Gifu University School of Medicine (approval No. 2024-020).
In developed countries, endometrial carcinoma is one of the most common carcinomas of female reproductive tract, and its incidence rate shows a significant upward trend.7) Distant organ metastasis is rare and reportedly occurs in approximately 4.2% of patients.8) Lung metastasis is the most common, followed by liver and bone metastases, whereas brain metastases are rare.7,8) Among these, orbital metastases are rare, with only few case reports available in the literature.9,10) In two reported cases, the metastatic orbital tumors invaded intracranially from the superolateral orbital wall, and tumor resection or biopsy was performed via the lateral wall of the orbit.
Orbital metastases isolated from the extraocular muscles are rare and are estimated to account for 5% of orbital metastases; there are no reports of metastasis to the extraocular muscles in endometrial carcinoma.11,12) A review of metastases to the extraocular muscles reported malignant melanoma, breast cancer, carcinoid tumors, lymphoma, gastric cancer, rhabdomyosarcoma, and lung cancer as the primary sites. Symptoms presented by metastases to the extraocular muscles include restricted eye movements (62.5%), proptosis (58.4%), diplopia (35.1%), eye pain (23.4%) and reduced visual acuity (13.0%).11) In addition to tumors, immunoglobulin G4-related ophthalmic and thyroid eye diseases should be considered in the differential diagnosis of extraocular muscle enlargement.13)
Orbital metastatic tumors have a poor prognosis; median overall orbital metastasis tumor survival time is 6 months, and the 1-year and 2-years survival rates are 40% and 29%, respectively.3) Among patients receiving chemotherapy and radiotherapy, those who underwent tumor resection had longer overall survival times than those who underwent biopsy.3) Radiotherapy has also been reported to contribute to local tumor control and is useful for symptom palliation. The most commonly used radiation regimens are 30 Gy/10 fr and 20-25 Gy/5 fr.4,14) Given the prognosis of an orbital metastasis tumor, symptom palliation should be emphasized to maintain the quality of life (QOL).4,14,15) However, acute adverse effects of radiotherapy include skin erythema and conjunctivitis. Moreover, in patients with expected long-term survival, attention should also be given to late complications such as cataract, radiation retinopathy, and optic neuropathy.15,16)
Surgical strategies for orbital tumors include transcranial, transorbital, and endonasal approaches, and the optimal choice varies depending on the tumor location and size. In our case, we selected the endoscopic endonasal approach because the tumor was located in the inferomedial portion of the orbit.
Previous reports have demonstrated that the endoscopic endonasal approach allows resection of intraconal tumors; however, complications such as ocular motility disorders and trigeminal nerve dysfunction have also been reported.17,18) She had advanced cancer with distant metastases, and we considered it important to achieve symptomatic improvement with a minimally invasive procedure in order to preserve her QOL. Endonasal endoscopic orbital decompression by removal of the orbital wall has been reported to be effective for pain relief in patients with orbital metastasis, and decompression including the orbital inferior wall has also been reported to improve proptosis and diplopia associated with Graves' ophthalmopathy.19-21) The pathological examination confirmed metastatic tumor; therefore, we performed partial tumor resection combined with orbital decompression through removal of the orbital inferior wall, aiming to relieve symptoms while minimizing damage to surrounding tissues to prevent complications. Postoperatively, her symptoms improved quickly, with no complications, and early discharge to home was possible. In addition, local tumor control of the residual lesion was achieved with radiotherapy. Although the patient died 4 months after the surgery due to poor systemic disease control, there was no recurrence, and symptomatic improvement was maintained. The treatment strategy consisting of symptom improvement by endoscopic endonasal surgery followed by postoperative radiotherapy was considered beneficial; therefore, therapeutic intervention was considered useful for improving symptoms.
Metastasis of endometrial cancer to the extraocular muscles is rare. When ocular symptoms develop in patients with endometrial cancer, metastatic lesions should be considered. In our case, the combination of minimally invasive surgery for early symptomatic relief and postoperative radiotherapy appeared to be effective for orbital metastasis from endometrial cancer.
We would like to thank Editage (https://www.editage.com/) for English language editing.
All authors have no conflict of interest.
