a 55-year - old man who was a known case of scapular bone osteosarcoma , was referred to our clinic with ocular symptoms including acute painful decreased vision , proptosis , conjunctival injection , and chemosis . he had undergone surgical excision of the original tumor and received systemic chemotherapy 4 months before . imaging studies and incisional biopsy were performed for the orbital lesion , the histopathological examination confirmed the diagnosis of metastatic osteosarcoma . the patient was referred to the oncologist for palliative chemotherapy and further intervention ; however , he deceased 2 months later due to sepsis in the context of immunosuppression . metastatic involvement of the orbit due to osteosarcoma is a rare condition manifesting with orbital mass , pain , diplopia and ocular motility disturbance . although there is no effective treatment , the combination of modalities such as chemotherapy , radiotherapy , and surgery may delay progression of the disease . metastatic orbital lesion due to osteosarcoma is a rare condition and manifestations include orbital mass , pain , diplopia , chemosis and ocular motility disturbance depending on the location of the mass and its effect on adjacent structures . there is no effective treatment , but the combination of treatment modalities including chemotherapy , radiotherapy and surgery for tumor debulking may delay disease progression . a 55-year - old man was referred to the oculoplastics clinic at farabi eye hospital , tehran , iran with acute onset painful decrease of vision and protrusion of his left eye . he was a known case of left scapular bone osteosarcoma and had undergone surgical excision of the original tumor and chemotherapy , approximately 4 months before . visual acuity was counting fingers and 20/20 in the left and right eyes , respectively . ophthalmic examination revealed proptosis , severe lid swelling , chemosis and conjunctival injection in his left eye [ figure 1 ] . appearance of the patient at presentation revealed proptosis , severe lid swelling and chemosis of the left eye . in the next step , orbital ct - scan revealed a large heterogeneous mass lesion in the left intraconal orbital space with tiny foci of hyperintensity [ figure 2 ] . for further investigation , mri was done in which an intraconal lesion , hypointense in some planes and hyperintense in others , was noted on t1 images [ figure 3a ] . the intensity of the lesion was heterogeneous to hyperintense on t2 images [ figure 3b and c ] which also displayed ring enhancement on gadolinium enhanced t1 images [ figure 3d ] . orbital mri showed an intraconal mass that was heterogeneous to hyperintense on t1 images ( a ) and heterogeneous to hyperintense on t2 images ( b and c ) with gadolinium enhancement at the rim of the lesion on t1 images ( d ) . in some sections , the mass seems to be hyperintense on t1 images ( a ) and in some others , hypointense ( d ) . histopathological examination of the tumor revealed malignant spindle cells with osteoid formation and mineralization which was compatible with metastatic osteosarcoma [ figure 4 ] . histopathological studies revealed malignant spindle cells with osteoid formation and mineralization compatible with metastatic osteosarcoma . the orbital metastasis being confirmed , the patient underwent systemic evaluation for any other site of metastasis ; however , there was no other organ involvement . unfortunately , after 2 months of chemotherapy , he deceased in the clinical setting of sepsis probably due to systemic immunosuppression . osteosarcoma is the most common malignant bone tumor and may involve the long bones of young adults primarily . it can be seen in association with hereditary retinoblastoma , previous exposure to ionizing radiation or paget disease . the most common site of involvement is the medulla of the metaphysis in long bones , particularly the distal femur , proximal tibia and proximal humerus . it has been classified conventionally into osteoblastic ( 50% ) , chondroblastic ( 25% ) and fibroblastic ( < 25% ) variants ; a small percentage of them are categorized into telangiectatic , small cell multifocal , parosteal , periosteal , and extra - osseous variants . factors affecting prognosis include tumor histopathology , size , raised pre- and post - operative serum alkaline phosphatase levels , involvement of lymph nodes and treatment modality . however , age , gender , history of trauma or bone fracture and the site of primary osteosarcoma do not influence prognosis . the most common sites for metastases for tumors originating from long bones is the lung and the second one are bones . by advances in systemic chemotherapy regimens , the long - term survival of patients without metastasis has now improved to 70% ; however , in patients with metastasis or disease recurrence , survival is < 20% . metastatic involvement of the orbit is a rare condition ; orbital metastasis can originate from any primary tumor in the body . the most common solid tumors in adults with orbital metastasis are breast and lung tumors , followed by cancers of the genitourinary tract and gastrointestinal system . some studies showed that leukemia and neuroblastoma are the most frequent causes of orbital metastasis . the most common symptoms of metastatic orbital osteosarcoma are pain , diplopia and ocular dysmotility . the patient was an 8-year - old boy with osteosarcoma in his right tibia with involvement of the right eye 1 month after the diagnosis . attili et al reported another case with right tibial osteosarcoma , painful protrusion of the right eyeball and metastatic orbital osteosarcoma . it is interesting that in all previously reported cases of metastatic orbital osteosarcoma , the primary and metastatic sites were both on the right side , but in the present case , both of them originated from the left side . in previous reports , the primary site of osteosarcoma was the right tibia and in our case , it was the left scapula which may explain left orbit preference . as the current case is only the fifth subject with metastatic orbital osteosarcoma , this finding can be purely coincidental . however , it is notable that in all cases with metastatic orbital osteosarcoma , the lung was not involved by metastasis . it is believed that spread of tumor cells to the orbit may occur through botson 's paravertebral venous plexus which has already been hypothesized in other studies . most metastatic osteosarcomas show hyperintense signal on t1 scans , whereas signal intensity was heterogeneous to high in our case . we assume that various amounts of necrosis , hemorrhage and mineralization in osteoid tissue may have resulted in this particular presentation on t1-weighted images . typical ring enhancement was seen on gadolinium enhanced images and a heterogeneous mass was revealed on t2 sections . combination therapy using different treatment modalities including radiotherapy , chemotherapy and surgery may be effective for palliative measures , maintenance of vision and regression of metastatic tumor .