Contributed by Hanni Gulwani, DNB, MRCPath1, Nitin Garg, MS, MCh2
Departments of 1Pathology and 2Neurosurgery, Bhopal Memorial Hospital and Research Centre, Bhopal, India
A 40-year-old woman presented to the Neurosurgery Department with sudden onset of headache and altered sensorium for 2 days. On evaluation in the emergency department, she was drowsy, disoriented with Glasgow coma scale of 13/15 and right hemiparesis grade 3/5, with no cranial nerve deficits. She was earlier diagnosed to have diffuse osteomalacia three years back and was on treatment for the same. Her serum phosphate levels (1.5mg/dl) were low, calcium levels (9.2mg/dl) were normal and vitamin D levels (40nmol/l) were reduced. Cause for the same could not be ascertained despite several investigations.
An urgent CT scan of the head was performed which revealed blood in the left medial temporal region that was seen extending to the suprasellar cistern. It was associated with diffuse subarachnoid hemorrhage with intraventricular extension (Figure 1). CT angiography was negative for an intracranial aneurysm. The posterior communicating artery and apex of basilar artery were, however, displaced and shifted to the right. An MRI of the brain showed an extra-axial mass in proximity to the dorsum sella causing distortion of the midbrain (Figure 2 T1) with heterogeneous contrast enhancement along with intraparenchymal bleed (Figures 3, 4, 5 T1 with contrast). A skull based meningioma was considered.
As patient had significant mass effect due to hematoma with features of raised intracranial pressure, she underwent an emergency left temporal craniotomy (navigation guided) with transcortical approach (through middle temporal gyrus) and evacuation of the hematoma. After evacuating the hematoma, tumor was encountered. Tumor was firm in consistency and moderately vascular. It was gradually mobilized after the internal decompression. The posterior portion indenting the brain stem could be mobilized with intact arachnoid between the tumor and brainstem. The medial part of tentorium was visualized and was free from the tumor. Third nerve was noted on the undersurface of tentorium, which was free from the tumor and was preserved. Last portion of the tumor appeared to be adherent to the posterior clinoid and posterior communicating artery. This couldn't be mobilized and was left behind. Postoperatively, patient recovered well. She was alert and conscious with no motor nerve deficits. However, she had third nerve palsy. Postoperative CT scan showed a small hematoma in tumor bed.
Histologic findings showed a moderately cellular neoplasm composed of round to oval spindle cells that were arranged in sheets. Several variable sized and staghorn vascular channels were scattered throughout the tumor (Figures 6, 7). Small amount of normal brain tissue was also included (Figure 8). The individual tumor cells exhibited moderate amount of eosinophilic cytoplasm with indistinct cell borders. Nuclei were hyperchromatic with mild to moderate anisokaryosis (Figure 9). Additionally, several small to large clusters of mature adipocytes were noted throughout the tumor (Figure 10). Areas of hemorrhage, focal necrosis and thrombosed blood vessel were also present. There was no significant increase in mitotic activity (Ki-67 labelling index - less than 1%). Immunohistochemical studies revealed diffuse positivity for vimentin and scattered tumor cells and proliferating vessels were positive for CD 34 (Figure 11). The tumor cells were not reactive with EMA, factor VIII and GFAP. What is your diagnosis?