Cystic Mural Nodule in Cerebellar Hemangioblastoma

Central nervous system capillary haemangioblastoma: the pathologist's viewpoint

Haemangioblastomas are rare neoplasms of uncertain histogenesis. They represent 1.5-2.5% of intracranial tumours. While the cerebellum is by far the most frequent site, these lesions also tend to occur in the medulla and spinal cord. Most haemangioblastomas are sporadic but up to one quarter are associated with Von Hippel-Lindau disease (VHL). Although a fairly good number of haemangioblastomas were reported, a lack of side-by-side analysis of these reports has resulted in tentative conclusions that merely offer a first glimpse at their clinicopathologic diversity and histogenesis. To remedy this issue, this study presents a literature review concerning these lesions. Medline literature including both relevant monographs and clinicopathological case series. Haemangioblastomas occur either as a part of VHL disease (25-30%, inherited mutation of VHL gene on 3p25-26 chromosome) or as sporadic tumours (often with somatic mutation of VHL gene). They have diverse clinicopathologic presentations with cerebellar lesions having a better prognosis than their brainstem counterparts. Immunostaining is important for separation of haemangioblastomas from other tumours with similar histology. The rich vascularity of haemangioblastomas is due to overexpression of vascular endothelial growth factors. Moreover, 'stromal' cells represent the neoplastic cells of haemangioblastomas and are capable of forming blood islands with extramedullary haematopoiesis.

Preoperative embolization of brain and spinal hemangioblastomas

Large hemangioblastomas can be difficult to resect because of excessive bleeding. We report our experience with two patients whose large hemangioblastomas were embolized preoperatively and were totally resected with minimal blood loss and satisfactory postoperative outcome. Embolizations were carried out within 3 days of surgery, with the patient under general anesthesia, with 150- to 250-microns Contour emboli. A 65-year-old woman with progressive, severe myelopathy from a 4.5 x 2.1 x 1.4 cm intramedullary hemangioblastoma at T4 underwent embolization of the left T2 and T3 intercostal arteries; a 29-year-old man with Lindau's syndrome and posterior fossa hemorrhage from a 3.8 x 1.8 x 1.8 cm right cerebellar hemangioblastoma underwent embolization of the right posterior inferior cerebellar artery, two right anterior inferior cerebellar arteries, and a dural branch of the right vertebral artery. Embolization led to the complete obliteration of the tumoral blush without neurological sequelae. Both lesions were completely resected with a blood loss of 50 to 100 ml, with bleeding occurring mainly from the pseudocapsule of the lesion. Preoperative embolization of hemangioblastomas is a useful and relatively safe procedure that reduces blood loss at the time of surgery and allows complete resection.

Cystic acoustic schwannomas

Three cases with large space-occupying cysts in the cerebellopontine angle are reported. CT and MRI findings were not typical for acoustic schwannomas but at operation, besides the large cysts, small acoustic schwannomas could be detected and removed. The clinical and neuroradiological features of this unusual variety and the CT and MRI differential diagnosis of cerebellopontine angle lesions are discussed.

Contribution of MRI in the diagnosis of haemangioblastomas

Magnetic resonance imaging (MRI) patterns of 11 haemangioblastomas examined with a 1.5-T scanner are described. MRI was as effective as contrast-enhanced CT in the detection of vascular tumour components, but was less sensitive than angiography. MRI was superior to CT in delineating the exact extent of the lesions, for example contact with the arachnoid surface. Even if a cystic tumour component is absent, MRI can provide helpful criteria for differential diagnosis; in particular, T2 values allow differentiation from meningiomas. In three patients additionally administered gadolinium (Gd) diethylenetriaminepenta-acetic acid (DTPA) the angiomatous parts of the tumour showed a remarkable decrease in T1 value, but the time dependence of the enhancement was not the same as that seen in dynamic CT.