Brain Pathology Case of the Month - March 2007

Contributed by Atik Baborie 1, Arundhati Chakrabarty, Sarin Kuruvath, Paul Roberts5, Jake Timothy 2, Graham Bonsor 3, Phillip van Hille 2, Leslie R. Bridges4
Departments of Neuropathology, Neuroradiology3, Neurosurgery2 and Cytogenetics5, Leeds Teaching Hospitals NHS Trust, Leeds, UK
4 Division of Clinical Neurosciences, Southampton General Hospital, Southampton, UK
1 Department of Neuropathology, Newcastle General Hospital, NE4 6BE, Newcastle upon Tyne, UK


A 30-year-old white male was diagnosed with a left parietal parafalcine lesion in 1992. He had presented with headaches, dizziness and a generalized tonic clonic seizure. There was an 8 year history of carbamazapine controlled Jacksonian type seizure of the right arm and leg. He smoked 15 cigarettes a day. Neurological examination and fundoscopy were normal on admission. A stereotactic biopsy of the left parietal para-falcine lesion was performed. Subsequently, he received a total dose of 54 Gy radiotherapy in 30 fractions over 50 days. He presented again in January 2002 with 4 weeks history of seizures and a slowly progressive right hemiparesis. On examination he had grade 4/5 power in his right arm and leg and bilateral ankle clonus. Cranial nerves and fundoscopy were normal. A tumor (at the same area of the previous tumor) was debulked using a interhemispheric approach.


In 1992 brain MRI showed a well defined left parietal parafalcine hypodense lesion with no mass effect or contrast enhancement (figure 1). In 2002 MRI scan of the brain with and without contrast showed a well-defined enhancing lesion left parietal parafalcine (figures 2a and 2b).


In 1992 microscopy showed a tumor comprising protoplasmic astrocytes forming microcysts. Nuclei were moderately pleomorphic. A few large nuclei were seen. Mitosis and necrosis were not present (figure 3, H&E x200).

In 2002, histology showed a malignant neoplasm composed of densely packed, small dark cells with a scanty cytoplasm arranged in sheets. Scattered bizarre larger, multinucleated cells were present. Nuclei were pleomorphic and hyperchromatic. Mitoses, necrosis thrombosed vessels and clusters of lymphocytes were found (figure 4a, H&E x 200). Immunohistochemistry showed marked cytoplasmic NCAM and synaptophysin (figure 4b) immunopositivity. GFAP immunopositivity around vessels and between tumor cells were present but only a few actual tumor cells were positive (figure 4c). CD99 showed perivascular clusters of immunopositive cells. LCA, chromogranin, CAM 5.2 and NFP were immunonegative. Virtually all tumor cells nuclei were immunopositive for the proliferation marker MIB-1 (Figure 4d) and p53 (figure 4e) was expressed in the majority of the nuclei .

Electron microscopy showed undifferentiated round cells with pale, featureless cytoplasm showing a few tubules, filaments and calcific bodies.

Cytogenetic analysis in the biopsy from 2002 showed an abnormal hypodiploid clone: 43-46 chromosomes, loss of chromosome 1 and 13q, an unbalanced 4q rearrangement, a balanced translocation t(12;15) and a marker chromosome of unidentified material. Other random abnormalities were detected which could possibly be treatment related. These abnormalities, however, were not suggestive of a PNET.

What is the diagnosis of the 1992 lesion?
What is the diagnosis of the current lesion?
How are they related?


International Society of Neuropathology