An 81-year-old man presented to the emergency room with a loss of consciousness and inability to speak. According to the patient's companion, he has lost the ability to walk for two months. they reported a vague history of the head tumour from the past that had increased in size over time.
Scout image of brain ct scan shows significant soft tissue swelling associated with an aggressive speculated mass in the posterior aspect of the skull (Fig.1).
CT scan revealed a large solid cystic mass over LT parieto-occipital bone with a bony defect in the medial aspect of the LT parietal bone due to bony erosions. A typical "sunburst" appearance compatible with aggressive periosteal reaction associated with adjacent calvarial bone thickening is noticed. Calcified foci in the soft tissue component of mass are consistent with the osteoid matrix. Complete obliteration of posterior horn of LT lateral ventricle is demonstrated with 13mm shift of midline structure to RT side (Fig 2). In post-contrast images, heterogeneous enhancement associated with subdural compartment adjacent to mentioned mass with dural enhancement is shown. Some area of necrosis related to the aggressive nature of the mass is seen (Fig 3).
In bone window image, evidence of bone lesion with the osteoid matrix is noticed causes bone destruction. the classic sunburst appearance is seen either (Fig4).
Osteosarcoma is one of the most common bone tumours in young adults and adolescents, frequently occurring in the extremities; however, skull osteosarcoma is rare. Less than 1% are found in the cranial vault, and there have been only a few reported cases. It appears in the third to fourth decade of life, secondary to treatment with radiotherapy and chemotherapy, so primary osteosarcoma is encountered for fewer cases. Hence it seems to be more uncommon in the elderly. (1,2)
Osteosarcomas are spindle-cell tumours associated with excessive production of the immature osteoid matrix. The subtypes of Osteosarcomas are varied and can be classified based on histological appearance. The most common subtypes include osteoblastic, chondroblastic, and fibroblastic osteosarcomas. Other infrequent histological subtypes include parosteal, telangiectatic, small cell osteosarcomas, and periosteal subtypes. (3,4)
CT scan with bone and soft tissue windows plays a key role in diagnosis, in which heterogeneous mass with an osteoid matrix and lytic regions associated with malignant periosteal reactions are the most common imaging features. Searching for metastatic sites of osteogenic sarcoma is also a further evaluation in selective patients. A chest CT scan to evaluate lung metastasis and a radionuclide bone scan to detect skeletal metastases can be used. (5,6)
wide surgical excision including margins has been associated with improved survival. dural enhancement indicates tumor invasion, so excision of involved dura is the main factor of achieving utmost resection. Although the anatomy of the head could restrict aggressive resection because it can cause significant functional impairment or cosmetic defects. local recurrence is the leading reason for treatment failure and decrease 5-year survival rates. Due to the difficult achievement of complete surgical excision and likely to have positive tumour margins, adjuvant therapy is needed in most cases. (7,8)
The patient was discharged with personal consent, and Unfortunately, he died two days later.
Due to the rarity of the osteosarcoma of the skull, it is not easy to make a definitive diagnosis based on imaging data. However, a characteristic destructive lesion with a soft tissue mass and an aggressive periosteal reaction (typical sunburst appearance) can facilitate the diagnosis and lead to proper treatment.
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Primary osteosarcoma of skull
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From the provided skull X-ray and CT images, the following findings are observed:
Considering the patient’s advanced age (81 years), the lesion located in the skull, the clinical manifestations (altered consciousness, speech and motor dysfunction), and the imaging features, the possible diagnoses include:
Based on the patient’s age, a prior history of a head tumor, acute clinical deterioration, and the characteristic radiographic features of radiating periosteal reaction and bone destruction, the most likely diagnosis is:
Osteosarcoma of the Skull
For further confirmation, a biopsy or intraoperative frozen section could be performed.
Since the patient exhibits significant neurological deficits (speech and motor impairments), individualized and gradual rehabilitation training should be performed within the limits of the condition. If the patient’s status stabilizes or after surgical intervention, consider:
This report is a reference based on the existing medical history and imaging data. It does not replace an in-person consultation or the medical judgment of professional physicians. Please strictly follow the evaluation and recommendations of specialized doctors or medical institutions for specific diagnosis and treatment.
Primary osteosarcoma of skull
