Primary intracerebral osteosarcoma: a rare case report and review

A 54-year-old female was referred to our institution with a 1-week history of headaches. Her past medical history was unremarkable. Magnetic resonance imaging (MRI) revealed a large, partially necrotic and calcified tumor in the parenchyma of the left frontal lobe with marked surrounding edema and mass effect on midline structures, but without any dural attachment. The tumor appeared hypointense on non-contrast T1-weighted images (Fig. 1a) and iso-to hyperintense on T2-weighted images (Fig. 1b). The enhancement of the tumor was irregular and most prominent at its periphery (Fig. 1c–e). The preoperative clinical diagnosis was meningioma or calcified glial tumor. She underwent incomplete resection of the tumor and histopathologic examination revealed a malignant mesenchymal neoplasm displaying a poorly differentiated spindle cells with interspersed eosinophilic osteoid production, calcification intimately associated with the malignant cells, and localized new bone formation (Fig. 1f). Immunohistochemistry was negative for epithelial membrane antigen (EMA), glial fibrillary acidic protein (GFAP), CD34, desmin and neurone specific enolase (NSE) but positive for vimentin (Fig. 1g), P53 (Fig. 1h), osteopontin (Fig. 1i) and osteonectin (Fig. 1j). Antisera against the proliferation marker Ki-67 revealed very variable immunoreactions (80%). Given the microscopic appearance a histopathologic diagnosis of primary intracerebral osteosarcoma was made.

We performed a PubMed search for all cases of primary intracerebral osteosarcoma up to September 2016. Cases were analyzed for basic demographic features including age, sex, chief complaint, location, treatment, and clinical outcome (Table 1).

Study	Age/gender	Chief complaint	Location	Treatment	Clinical outcome
Jacques et al. (1976)	53/male	Headaches and left arm weakness	Right temporo-parietal lobe	Surgery, radiotherapy	Dead at 5 months
Reznik and Lenelle (1991)	64/male	Headaches and left side hemiparesis	Right thalamus	Surgery	Dead at 3 days
Ohara et al. (1994)	57/female	Headaches	Right parietal lobe	Surgery, radiotherapy, chemotherapy	Dead at 1 year
Sipos et al. (1997)	16/female	Headaches and impaired vision	Left parietal lobe	Surgery, radiotherapy, chemotherapy	Alive at 4 years
Bauman et al. (1997)	3/female	Seizure	Right temporal lobe	Surgery, radiotherapy, chemotherapy	Alive at 18 months
Hettmer et al. (2002)	78/male	Right side weakness	Left frontal lobe	Surgery	Recurrence at 4 months