Primary intracranial sarcomatoid carcinoma arising from a recurrent/residual epidermoid cyst of the cerebellopontine angle: a case report.

Primary intracranial squamous cell carcinomas (SCCs) are rare and mostly associated with an intracranial epidermoid or dermoid cyst. Sarcomatoid carcinoma is a rare biphasic tumor composed of both carcinomatous and sarcomatous components and has not previously been reported as a primary intracranial tumor. Here, we present a case of a 60-year-old man with a primary intracranial sarcomatoid carcinoma, arising from the remnants of the previously resected epidermoid cyst in the cerebellopontine angle. The resected material had portions of an epidermoid cyst lined by normal and dysplastic squamous epithelia and invasive keratinizing SCC. This area was in continuity with areas of highly pleomorphic, anaplastic sarcomatoid cells. Brisk mitotic activity and extensive areas of necrosis were found. On immunohistochemical staining, the cells of the conventional SCC were positive for cytokeratin 5/6, pancytokeratin, epithelial membrane antigen, p63, and p53. The sarcomatoid cells were diffusely and strongly positive for vimentin, p53, smooth muscle actin, and, focally, muscle-specific actin. Occasional sarcomatoid cells coexpressed cytokeratin 5/6, pancytokeratin, p63, and S100 protein. The patient subsequently developed leptomeningeal spread and died 4 months after the second surgery. This rare entity expands the morphologic spectrum encountered in primary intracranial carcinoma.

Dissemination of fat in CSF: a common finding following translabyrinthine acoustic neuroma surgery*.

OBJECTIVES: Following translabyrinthine craniotomy the temporal bone defect is commonly obliterated using a free autologous fat graft. In this series the dura was put back in place but not closed primarily. As the fat graft remains in direct contact with the cerebro spinal fluid (CSF) there is potential for dispersal of fat within the CSF space. This paper aims to determine the frequency of such CSF fat dissemination and its clinical significance. DESIGN: A retrospective review of translabyrinthine acoustic neuroma removal with free fat autograft obliteration of the temporal bone defect between the years 1997 and 2000. SETTING: Tertiary referral oto-neurosurgical centre. Postoperative magnetic resonance (MR) imaging. PARTICIPANTS: All translabyrinthine patients who had postoperative MR imaging were included. Twenty-six cases were identified. Age range was 13-70 years. Fourteen were male patients. MAIN OUTCOME MEASURES: Evidence of CSF fat dissemination on MR and patients' clinical findings. RESULTS: Twenty-two of the 26 scans (85%) demonstrated evidence of fat dissemination into the subarachnoid CSF spaces in the form of microemboli. The cerebellopontine angle was the most common site involved. No evidence of ventricular dilation or any other abnormality was noted. There was no relationship between the presence or extent of fat microembolization and the patients' clinical course. CONCLUSIONS: This study suggests that free fat placed in temporal bone defects commonly migrate into the subarachnoid space and subsequently move around in these spaces. This is not associated with any complications such as hydrocephalus, meningitis or prolonged postoperative headache.

Endodermal cyst in the cerebellopontine angle with immunohistochemical reactivity for CA19-9.

We present a rare case of the endodermal cyst in the cerebellopontine angle with positive immunohistochemical reactivity for CA19-9. The patient was a 67-year-old woman with an endodermal cyst in the cerebellopontine angle who presented with progressive gait disturbance. A magnetic resonance image showed a cerebellopontine angle which was low in signal on T1-weighted, and high on T2-weighted image without gadolinium enhancement. The preoperative diagnosis was an epidermoid or arachnoid cyst. The patient underwent surgery. Since the intraoperative histological diagnosis by frozen section was endodermal cyst, total removal of the cyst wall was achieved for preventing recurrence. The postoperative definitive histological diagnosis was endodermal cyst, type A by Wilkins-Odom classification, lined by mucinous epithelium with an immunohistochemical reactivity for CA 19-9 protein and cytokeratin. This is the first reported case of a huge endodermal cyst in the cerebellopontine angle of an elderly woman which exclusively showed a differentiation toward the midgut epithelium. The histological diagnosis during surgery by frozen section should be performed for proper treatment.