A 68-yr-old African-American woman was admitted to an acute tertiary general hospital with a 1-wk history of increasing somnolence, headache, lower extremity weakness, and blurred vision. She was brought to the hospital when her family was unable to arouse her.
A magnetic resonance imaging scan revealed a cerebellar tumor with tonsillar herniation (Fig. 1). The tumor was 5 cm in diameter and centrally calcified. It was located in the left posterior fossa and extended through the tentorium into the juncture of the left transverse and sigmoid sinuses. The fourth ventricle was obstructed with a resultant hydrocephalus. There was also a mass effect causing a cerebellar tonsillar herniation. The tumor was resected the next day.
Pathology was reported as an atypical meningioma. The diagnosis was made because the proliferation index, defined as percentage of cells actively dividing, was reported at 18.4. Although there is no clear consensus on the pathologic criteria to diagnose an atypical meningioma, a proliferation index ≥4.2% is considered atypical.1 The tumor demonstrated increased cellularity, mild cytologic atypia with slightly spindled cells forming distinctive whirls (Fig. 2) with psammoma bodies. Of note, psammoma bodies are commonly seen in low-grade meningiomas.2
Atypical meningiomas are rare. Meningiomas comprise 13–26% of all intracranial tumors.1 Only 4.7–7.2% of all meningiomas are reported as atypical.1 Usual locations of atypical meningiomas are not reported. About 9–15% of all meningiomas do occur in the posterior fossa.3 Treatment usually includes surgical resection.1 Radiation therapy is recommended for those with tumors with brain invasion.1 Recurrence rate with gross total surgical resection has been reported as high as 87%.4
The patient had no history of cancer and no family history of brain tumors. She did have hypertension, diabetes, and was status post-right transmetatarsal amputation.
After acute stabilization, the patient was transferred to the hospital rehabilitation unit. Her program in inpatient rehabilitation emphasized transfers, gait training, strengthening activities, and activities of daily living. On admission, she was ambulating 60 feet with minimal assistance, whereas at discharge she was ambulating 200 feet with a rolling walker with supervision. She had also made gains in her activities of daily living only requiring minimal assistance with bathing and lower body dressing. Her main limitation was balance, which could vary from day to day. At the time of discharge, there were no other plans for radiation.
1. Mohda A, Gutin P: Diagnosis and treatment of atypical and anaplastic meningiomas: a review. Neurosurgery
2. Kumar: Robbins and Cotran: Pathologic Basis of Disease
, ed 7. Saunders, An Imprint of Elsevier
3. Asthagri A, Helm G, Sheehan J: Current concept in management of meningiomas and schwannomas neurologic clinics. 2007;25:1209–30
4. Dziuk T, Woo S, Butler EB, et al: Malignant meningioma: an indication for initial aggressive surgery and adjuvant radiotherapy. J Neurooncology