Contributed by Hanni Gulwani, DNB, MRCP and Subimal Roy, MD, PhD
Department of Histopathology, Sir Ganga Ram Hospital, New Delhi, India
A 44-year-old man was hospitalized with an acute onset of giddiness, drunken gait and tendency to fall. He was apparently well until one week prior to presentation. He experienced these symptoms after drinking heavily at a party. There was no history of trauma, headache, vomiting or seizures.
On neurological examination, there was no motor or sensory deficit. Finger-to-nose testing revealed mildly abnormal coordination. The patient tended to sway and fall sideways on heel-to-toe walking. Romberg's test was mildly positive. Meningeal signs were absent.
Computerized tomographic (CT) scan revealed a large hyperdense calcified lesion in the fourth ventricle. MRI scans showed a fourth ventricular space-occupying lesion with mild hydrocephalus. Craniectomy with endoscopic fourth ventriculostomy was performed. A reddish brown tumor mass was encountered measuring 30 mm x 20 mm attached to the floor of the fourth ventricle. The tumor was almost entirely resected.
Histopathological examination revealed a moderately cellular tumor with large areas of calcification (Fig. 1 and Fig. 2). The tumor cells were arranged in groups and cords as well as showing papillary formation in many areas. The tumor cells were generally large and contained brightly eosinophilic granular cytoplasm with central nuclei (Fig 3). There was only mild nuclear pleomorphism and mitoses were rare.
Immunohistochemical staining showed that many of the neoplastic cells had strong positive reaction for S-100 protein (Fig. 4). Some of these cells were also positive for cytokeratin (CK), epithelial membrane antigen (EMA) and glial fibrillary acidic protein (GFAP) (not shown).