A Comparative Analysis of Drug Laws in France, UK, and USA
Drug laws in France, the United Kingdom, and the United States are compared in terms of history, policies, results, and reforms. The differences in categorizing drugs, punishments for drug crimes, and enforcement methods are discussed. The United States' high incarceration rate is highlighted, along with the UK's Misuse of Drugs Act and policy developments.
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HEMANGIOBLASTOMA DR. FARRUKH JAVEED NEUROSURGERYJPMC
HAMANGIOBLASTOMA These are slow growing benign vascular neoplasm. They arises from the hemangioblast cells. Classified as WHO grade I tumors. There are 2 Subtypes: Reticular; morecommon Cellular
Location Hemangioblastomas are found nearly exclusively(over 95%) in the brainstem, spinal cord(2 to 10%) cerebellum They account for 7% to 12% of posterior fossatumors. About 1-5% of hemangioblastomas are found in the supratentorial compartment, most frequently (30%) originate in the region of the pituitary stalk andtuber cinereum. 10% of patients with VHL disease have supratentorial hemangioblastomas. Other locations that can be involved are: Optic Nerves Peripheral Nerves Soft Tissues
Epidemiology M:F is2:1 Age: 30 - 50 Uncommon (1-3% of all intracranial neoplasms) Hemangioblastoma-related symptoms typically occur earlier in patients with VHL disease (30 to 40 years) than in those with sporadic tumors (40 to 50 years). Sometimes referred to as LindauTumors
ETIOLOGY/ASSOCIATION Sporadic (75%) Von Hippel Lindau Disease (25%)
VON HIPPEL-LINDAU DISEASE a familial neoplasia syndrome with autosomal dominant transmission caused by a VHL gene germline mutation. Visceral manifestations include renal cysts, renal carcinomas, pancreatic cysts, pancreatic neuroendocrine tumors, pheochromocytomas, and adnexal organ cystadenomas (broad ligament and epididymis). CNS manifestations include hemangioblastomas (the most common manifestation of VHL disease) and endolymphatic sactumors. the primary cause of VHL disease related death is renal cell carcinoma or CNShemangioblastoma.
PATHOLOGICFINDINGS Hemangioblastomas are bright red or red-orange and areinvariably associated with intense vascularity. Typically, large abnormal veins are found at resection to be draining these tumors. Hemangioblastomas are well-circumscribed, encapsulated tumors that occasionally have intratumoral cysts but more frequently are associated with peritumoral cysts whose walls are composed of compressed brain tissue and reactive gliosis. Histologically, the tumors are characterized by proliferation of stromalcells and endothelial cells.
PATHOLOGICFINDINGS These tumors often appear histologically similar to renal cell carcinoma metastases. Further, because patients with VHL disease often have contemporaneous renal cell carcinomas that can metastasize to the CNS or metastasize to hemangioblastomas, immunohistochemical differentiation between renal cell carcinoma and hemangioblastoma may be necessary. Jarrell and colleagues reported that 8% of a series of CNS hemangioblastomas removed from consecutive patients with VHL disease had either a renal cell carcinoma or pancreatic neuroendocrine tumor that had metastasized to a coexisting hemangioblastoma.
PERITUMORALCYST About 80% of CNS hemangioblastomas are associated with a peritumoral cyst. About 70% of symptomatic cerebellar and brainstem hemangioblastomas are associated with peritumoral cyst, and more than 90% of symptomatic spinal cord hemangioblastomas are associated with peritumoral cyst (syringomyelia). Alternatively, asymptomatic cerebellar, brainstem, or spinal cord hemangioblastomas are uncommonly associated with peritumoral cysts (only 5% to 10% of tumors with cysts).
PERITUMORAL CYST FORMATION Increased vascular permeability of the hemangioblastoma. Extravasation of a plasma ultrafiltrate into the tumor interstitial spaces. High interstitial tumor pressure then drives this fluid into the surrounding CNS parenchyma. Peritumoral edema forms when the resorptive capacity of the peritumoral tissue is exceeded. As the mismatch between fluid production and tissue resorption increases, the surrounding tissues swell owing to solid stresses (stretching) that favor cyst formation. The formation of a cyst changes the interstitial flow patterns, and most of the excess interstitial fluid flows along the path of least resistance into the peritumoral cyst, expanding it.
Because the hemangioblastoma is the source of extravasated plasma ultrafiltrate, peritumoral edema and cysts resolve after tumor removal, and treatment does not require cyst wall resection or fenestration.
CLINICAL FEATURES Depend on location Cerebellar Hemangioblastomas headache (70% to 80% ofpatients) gait ataxia (55% to65%) dysmetria (30% to65%) hydrocephalus (20% to30%) nausea and vomiting (5% to30%) Brainstemhemangioblastomas hypoesthesia (40% to55%) gait ataxia (20% to30%) dysphagia (20% to30%) hyperreflexia (20% to25%) headache (10% to20%) disorders of appetite and feeding (2% to5%)
Spinal cordhemangioblastomas hypoesthesia (80% to90%) weakness (60% to70%) gait ataxia (50% to65%) hyperreflexia (40% to60%) pain (10% to30%). Eye Visual Changes likediplopia ElevatedErythropoietin Secondarypolycythemia
RADIOLOGY 15 MRI of the brain andspine Angiography CT Abdomen - evaluate thekidneys, pancreas, adrenals
MRI with Contrast 16 The most sensitive and accurate imaging modality. Discretely enhance on T1-weighted MRI sequences after infusion of a gadolinium-based contrast agent. Even small tumors (2 to 3 mm in diameter) can be detected. Peritumoral edema and cysts are best detected and monitored with fluid- attenuated inversion recovery (FLAIR) or T2-weighted MRI sequences.
T1-weighted, contrast-enhanced axial image of a cerebellar hemangioblastomas (solidly enhancing area) with an associated cyst (homogenous associated dark region) in a 40-year-old woman with VHLdisease.
Midsagittal T1-weighted postcontrast image of a medullary hemangioblastoma (solidly enhancing region) with associated brainstem edema (surrounding darker region) in a 12-year-old girl with VHL disease.
Midsagittal postcontrast T1-weighted imageof the cervical region of the spinal cord of a 50- year-old man with VHLdisease.
Postcontrast sagittal (A) and axial (B)images reveal an intensely enhancing hemangioblastoma with an associatedsyrinx. T2-weighted sagittal (C) and axial (D) images precisely define the extent of the syrinx and the edema associated with this tumor. A C B D
Angiography 21 Angiography of vessels supplying and draining a hemangioblastoma reveals a highly vascular tumor nodule with prolonged contrast staining that can be associated with an avascular peritumoral cyst.
MANAGEMENT Screening for VHL gene using molecular genetic testing. Endovascular embolization Open Surgical resection Radiosurgery Antiangiogenic treatment
Von Hippel-Lindau DiseaseRelated versus Sporadic Hemangioblastomas The management strategy for hemangioblastomas of these 2 categories aredifferent. Because most patients with VHL disease have multiple CNS hemangioblastomas and because the growth rate of these tumors is unpredictable, treatment of individual tumors is generally postponed until they become symptomatic. They maintain excellent neurological function over long-term evaluation, and unnecessary surgical resection can be avoided. Alternatively, patients with sporadic hemangioblastomas are frequently investigated because they have symptoms, and the diagnosis of hemangioblastoma cannot be confirmed until resection. Thus, to relieve symptoms and to provide a diagnosis in sporadic cases, surgery may be required.
Surgical Resection The treatment of choice for CNS hemangioblastomas is complete resection. Microsurgical resection is curative, and most craniospinal hemangioblastomas can be completely and safely resected. When the tumor is associated with a cyst (regardless of anatomic location), the gliotic cyst walls are left undisturbed, because they are not neoplastic and simply removing the source of the cyst (the tumor) inactivates thecyst, which and will collapse. This is the case regardless of the location of the tumor along the craniospinalaxis. When complete resection of the tumor is accomplished, recurrence is rare, and stabilization or improvement of symptoms occurs in more than 90% of patients.
Cerebellar Hemangioblastomas 25 Cerebellar hemangioblastomas are commonly (74%) located in the posterior and/or medial cerebellar regions. A midline suboccipital approach can most often be used to resect such tumors. A midline incision through the skin and dermis from the inion to the second cervical spinous process is made. The nuchal musculature is opened in the midline and stripped laterally in the subperiosteal plane over the suboccipital region and first and second cervical laminae. A suboccipital craniectomy is created with a high-speed drill and rongeurs from 1 cm above the upper edge of the tumor or the inferior edge of the transverse sinus (whichever is lower) to the foramen magnum. A laminectomy of the first cervical lamina can be used for additional caudal exposure.
26 A Y-shaped dural incision is made. The dural edges are secured laterally and superiorly. With a microscissors, the arachnoid is sharply opened to expose the underlying cerebellum and tumor. If necessary, increased posterior fossa pressure can be reduced by removal of cerebrospinal fluid from the cisterna magna or needle decompression of peritumoral or intratumoral cysts. The pia at the tumor-pia junction is circumferentially incised, providing clear exposure of the tumor capsule cerebellum interface. Deeper circumferential dissection precisely at the tumor capsule cerebellum interface is performed to remove the tumor from the surrounding tissue.
27 Once the capsule is clearly identified, the hemangioblastoma capsule cerebellum interface is precisely defined, and the tumor is removed by means of deeper circumferential dissection at the interface. Tumor- associated vessels (those entering and leaving the tumor) are cauterized with bipolar cautery and sharplydivided. After hemangioblastoma removal, the dura, nuchal musculature, fascia, and subcutaneous/cutaneous layers are closed in standard fashion. A sterile dressing is applied to the wound
Brainstem Hemangioblastomas Because most brainstem hemangioblastomas (60%) are located in the region of the medullary obex, a midline suboccipital-cervical approach is used to gain access to suchtumors. The dura and arachnoid are opened as described for cerebellar hemangioblastoma resection. For midline hemangioblastomas that do not extend to the posterior surface of the brainstem, a midline pial incision is made, and the posterior median raphe is separated to access the deeper tumors.
29 As with spinal cord hemangioblastomas, maintenance of awell-defined interface of the bright red or red-orange tumor surface with the surrounding brainstem is critically important because the inability to define this tissue plane and dissection into the brainstem risk serious neurological impairment. After hemangioblastoma removal, the dura, nuchal musculature, fascia, and subcutaneous and cutaneous layers are closed in standard fashion. A sterile dressing is put on the wound.
Spinal Cord Hemangioblastomas 30 Because most (96%) spinal cord hemangioblastomas are located posterior to the dentate ligament, a direct posterior approach is most often used to remove them. Hemangioblastomas located in the anterior (anterior to the dentate ligament) or anterolateral region of the spinal cord may be accessedwith an anterior or anterolateral approach. These direct approaches to anteriorly located tumors allow for minimal manipulation and rotation of the spinal cord during resection and canbe associated with improved postoperative outcome. Occasionally, anteriorly located tumors associated with rotation of the spinal cord can be best accessed from a posterior approach.
Spinal Cord Hemangioblastomas 31 The incision site is prepared and a midline incision over the spinous processes is made that provides exposure of at least one spinous process above and one below the rostral and caudal poles of thetumor. After skin incision, the paraspinous musculature is opened in the midline and stripped laterally in the subperiosteal plane over the involved lamina. With a high-speed drill and rongeurs, laminectomies are created. After bone removal (laminectomies), the dura is incised in the midline while the underlying arachnoid is kept intact. The dura is reflected laterally and temporarily secured with tacking sutures to the paraspinousmusculature.
Spinal Cord Hemangioblastomas 32 The operative microscope is used to sharply open the arachnoid with microscissors. Once the arachnoid is opened and the tumor is exposed, vessels entering the tumor are coagulated at the tumor-pia interface and then sharply transected starting at the caudal pole of thetumor. The hemangioblastoma capsule spinal cord pia interface is sharply opened with a diamond knife and microscissors in a circumferential manner. Dissection is continued at the rostral and caudal poles of the tumor with gentle retraction and elevation of the poles of the hemangioblastoma, which permits the deep anterior margin of the tumor tobe visualized and separated from the spinal cord.
Spinal Cord Hemangioblastomas For hemangioblastomas that originate in the dorsal nerve root entry zone, sensory nerve rootlets embedded in the tumor are cauterized and sharply interrupted at the margin of thehemangioblastoma. For tumor with associated peritumoral syrinx, avoid entering the syrinx if possible. Opening or drainage of an associated syrinx can result in magnification of the physiologic pulsations of the spinal cord and tumor. This accentuation of physiologic tumor movement during resection can make removal more difficult. Removal of the hemangioblastoma inactivates the syrinx, so syrinx drainage is not necessary. After hemangioblastoma removal, the dura, paraspinous musculature, fascia, and subcutaneous and cutaneous layers are closed in standard fashion. A sterile dressing is put on the wound.
Intraoperative view of a hemangioblastoma of the cervical spinal cord. Hemangiomas are bright red or orange-yellow, owing to thehigh lipid content of their stromal cells, and are invariably associated with large tortuous arterialized draining veins.
Preoperative (A) and postoperative (B) sagittal T2-weighted magnetic resonance images from a patient with von Hippel-Lindau disease and a hemangioblastoma in the cervical segment of the spinal cord and surrounding syrinx. After selective resection of the hemangioblastoma, complete resolution of the associated syrinx and surrounding edema has occurred. A B
POST-OPCOMPLICATIONS Hemorrhage Hydrocephalus Diplopia Hemiparesis
Outcome Generally curable with surgery Local recurrence after surgery is higher with thefollowing: VHLSyndrome MultipleHemangioblastomas YoungerAge CellularHistology Cellular type has a 20 - 25% recurrence rate Reticular type has a 5 - 10% recurrence rate Subarachnoid dissemination israre.
