Medulloblastoma+(adult)


 * **Epidemiolgy:** || The medulloblastoma is fairly rare in adults. It comprises less than two percent of all central nervous system tumors in adults.[1] ||
 * **Etiology:** || The exact cause of medulloblastomas is still unknown but, it is believed to originate from immature or embryonic cells. Medulloblastoma is also seen in patients with Golin syndrome and Turcot syndrome.[1] ||
 * **Signs & Symptoms:** || The early symptoms of medulloblastoma are usually due to increased intracranial pressure. This causes headaches, nausea, vomiting, and problems with vision, hearing and speech. The specific symptoms of medulloblastoma are muscle weakness, nystagmus (jerky eye movement), and seizures. [2] ||
 * **Diagnostic Procedures:** || * A complete history and general physical examination
 * Complete blood counts.
 * Assessment of mental condition, coordination, sensation, reflexes and motor and cranial nerves.
 * MRIs are the diagnostic procedure of choice for medulloblastoma in detecting changes to cerebellar tissue changes. Medulloblastomas show definite but often nonhomogeneous enhancement after contract administration.[3] ||
 * **Histology:** || Most frequent malignant brain tumor. Arise primarily from the cerebellum, namely cerebellar granule cell precursors that transform and fail to undergo differentiation. Composed of primitive neural cells with some medulloblastomas showing signs of differentiation along neuronal, glial, myogenic and rarely melanocytic or retinal lineages.[4] ||
 * **Lymph node drainage:** || Medulloblastoma rarely metastasize outside the CNS. ||
 * **Metastatic spread:** || Medulloblastoma is known to spread via cerebral spinal fluid and can be determined 30% of the time through presentation. The tumor may infiltrate subpial and parenchymal. Remote metastases are rare. Medulloblastomas may metastasize out of the central nervous system by ventriculoperitoneal shunts or other means. [5] ||
 * **Grading:** || Graded on a scale of I to IV World Health Organization [WHO] Grading system [5]

Grade I tumors are slow-growing, nonmalignant, and associated with long term survival. Grade II tumors are relatively slow-growing but sometimes recur as higher grade tumors. They can be nonmalignant or malignant. Grade III tumors are malignant and often recur as higher grade tumors. Grade IV tumors reproduce rapidly and are very aggressive malignant tumors. || T1: tumor ≤3cm, confined to cerebellum, vermis, roof of 4th ventricle T2: tumor >3cm, invading one adjacent structure or partially filling 4th ventricle
 * **Staging:** || Chang System [2]

T3a: tumor is invading 2 adjacent structures, complete filling 4th ventricle with proximal or distal extension

T3b: tumor arising from floor of 4th ventricle and/or brainstem and filling the 4th ventricle T4: Involving 3rd ventricle/ midbrain/upper cervical cord

M0: No evidence of gross subarachnoid or hematogenous metastasis

M1: Microscopic tumor cells in Cerebrospinal Fluid (CSF) M2: Nodular seeding intracranially beyond primary site (in cerebellar/cerebral subarachnoid space, 3rd or lateral ventricles)

M3: Nodular seeding in spinal subarachnoid space

M4: Extraneuraxial metastasis (outside cerebrospinal axis) || Alopecia Headaches Seizures Short term memory deficiency Decreased appetite Loss of balance and/or trouble walking Otitis externa Serous otitis media Dermatitis Hormone dysfunction High tone hearing loss Vestibular damage Nausea and vomiting Fatigue Dysphasia Secondary tumor Death Neuroendocrine dysfunction Neurologic deterioration: Can begin 6-12 months following radiation treatment. Radiation necrosis: Can appear after 6 months following radiation treatment with a peak at 3 years.[2,5] || //Cranial/helmet//: parallel-opposed fields with markers on the eyelids. The inferior border is placed at the lowest cervical vertebrae without treating the shoulders. The inferior border is decreased by 2 cm every 10 Gy to allow for junction movement and avoid cold spots in the cervical spine. //Spine//: the spinal field can be one extended distance field or a superior spinal field matched with an inferior spinal field. If the fields are split, the central axis of the superior field should be stationary. Shifts of the superior spine and cranial field junction and the superior spinal field and inferior spinal field are necessary to avoid areas of high or low doses. //Boost//: An additional boost to the preoperative tumor volume with a 2 cm+ margin is necessary to a total dose of 54-55 Gy. Wedged pairs or 3D conformal treatment fields should be used. Chemotherapy agents such as cyclophosphamide and platinum have been successful in treatment of medulloblastomas. [2,6] || Brain 45 Gy 50 Gy 60 Gy Brainstem 50 Gy 53 Gy 60 Gy  Cauda equina 60 Gy  Ear 55 Gy 55 Gy 55 Gy  Lens 10 Gy  Optic chiasm 50 Gy  Optic nerve 50 Gy  Retina 45 Gy  Spinal cord 47 Gy(20 cm) 50 Gy(10 cm) 50(5 cm) [2, 6] || [2] Chao KS, Perez CA, Brady KW. //Radiation Oncology-Management Decisions.// 2nd edition. Philadelphia, PA: Lippincott, Williams & Wilkins; 2002. [3] Sartor K. //Diagnostic and Interventional Neuroradiology//. New York, NY: Thieme; 2002. [4] Sandberg AA. //The Genetics and Molecular Biology of Neural Tumors//. Totowa, NJ: Humana Press; 2008. [5] Medulloblastoma. Website. Available at: https://online.epocrates.com/u/2924733/Medulloblastoma/Basics/Etiology. Accessed May 29th 2012. [6] Lenhard RE, Osteen RT, Gansler T. //The American Cancer Society's Clinical Oncology.// The American Cancer Society. 2001. [7] http://bjr.birjournals.org/content/80/951/209/F9.expansion.html Accessed May 30, 2012.
 * **Radiation side effects:** || Adults tend to experience acute side effects to a greater degree than children.
 * **Prognosis:** || Prognostic factors included age, tumor type, tumor grade, seizure symptoms, duration of symptoms, performance status, extent of resection, radiation doses. [4] Typically, women who are diagnosed at an older age with localized disease have the best prognosis. With a complete surgical resection, 5 year survival is around 60%. Higher risk patients may have better survival with the addition of chemotherapy. [6] ||
 * **Treatments:** || Complete surgical resection of medulloblastomas should be attempted. Postoperative radiation standard treatment is craniospinal irradiation with a boost to the primary tumor site. Radiation doses are 30-40 Gy in 1.6-1.8 Gy daily fractions with a posterior fossa boost to 50-55 Gy. It is important to include the cribriform plate in the treatment field because this is a common site of recurrence (likely due to concern of blocking the optic lens). Typically, patients are treated with cranial, spine, and boost fields.
 * **TD 5/5:** || __ ORGAN WHOLE ⅔ ⅓ __
 * **References:** || [1] Hansen KE, Roach M. //Handbook of Evidence-Based Radiation Oncology.// 2nd Edition. New York, NY: Springer; 2010.

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