Type 1 (5% of posterior fossa HBs) is a simple cyst without a macroscopic nodule.
Type 2 is a cyst with a mural nodule (60%).
Type 3, or solid tumors (26%).
Type 4, or solid tumors with small internal cysts (9%), are also seen in the cerebellum and predominate in the spinal cord.
Some authors have stated that type 1 is actually rare.
Several primary pathologic entities in diverse anatomic locations have the potential to simulate metastatic neoplasms histologically. Their misinterpretation as such may result in needless and extensive clinical evaluations that are intended to detect a presumed malignancy at another site. More importantly, mistakes of this type can deprive patients of surgical excisions that could be curative 3).
High b value DWI reflects diffusion more accurately than does regular b value. Results showed that ADC calculation by high b value (b = 4000) DWI at 3-T magnetic resonance imaging is clinically useful for differentiating hemangioblastomas from brain metastases 4).
Coexistence of hemangioblastomas and AVMs is extremely rare, and only 3 cases have been reported previously in the literature 6).
Surgical treatment may be curative in cases of sporadic HGB, not in VHL.
Solitary hemangioblastomas are for the most part considered benign, curable by total resection, except in those cases associated with von Hippel-Lindau disease.
Despite extensive literature describing the diagnosis, treatment, and prognosis of these lesions, 7) individual cases still present a surgical quandary given their frequently eloquent location and high degree of vascularity.
Bründl et al. retrospectively analyzed the clinical, radiological, surgical, and histopathologic records of 24 consecutive patients (11 men, 13 women; mean age 51.3 years) with HBL of the posterior cranial fossa, who had been treated between 2001 and 2012.
Mean time to diagnosis was 14 weeks. The extent of resection (EOR) was total in 20 and near total in 4 patients. Four patients required revision within 24 h because of relevant postoperative bleeding. One patient died within 14 days. One patient required permanent shunting. At discharge, 75% of patients [n = 18, modified Rankin scale (mRS) 0-1] showed no or at least resolved symptoms. Mean follow-up was 21 months. Two recurrences were detected during follow-up.
In comparison to other benign entities of the posterior fossa, time to diagnosis was significantly shorter for HBL. This finding indicates the rather aggressive biological behavior of these excessively vascularized tumors. In this series, however, the rate of complete resection was high, and morbidity and mortality rates were within the reported range 8).
Cerebrospinal fluid dissemination of cerebellar hemangioblastoma was found dominantly in non-Von Hippel-Lindau disease patients. The diagnosis was made 10 years after the initial surgery. Irradiation therapy was performed, but the patients died about 2 years after the diagnosis was given. Molecular targeted therapies including vascular proliferation suppression have been attempted lately, but no effective therapy has been established. Early diagnosis of dissemination as well as combination of aggressive excision and stereotactic radiosurgery are considered to be appropriate for current interventions 9).