â€˘ General: Craniopharyngiomas are suprasellar tumors that are thought to derive from the vestigial remnants of Rathkeâ€™s pouch. They are slow-growing tumors, which account for about 1-5% of intracranial tumors. Abnormalities in Wnt signaling pathway, including activating B-catenin mutations, have been reported. They exhibit benign histology yet malignant behavior, as they have the tendency to involve nearby structures and recur after complete resection.
â€˘ Pathology: Craniopharyngiomas average 3-4cm in diameter, may be encapsulated, solid, and most often cystic. They often encroach on the optic chiasm or cranial nerves. There are two histological variants; Ademantinomatous and Papillary. Ademantinomatous is most often seen in children and this type frequently contains radiologically demonstrable calcifications, these dystrophic calcifications are a frequent finding.
â€˘ Epidemiology: Overall incidence of craniopharyngiomas in the US is 0.13 per 100,000. They display a bimodal age distribution, one peak in childhood (1-15 years old) and the second peak in adults >65 years old.
â€˘ Physical Findings: Symptoms most often develop insidiously and only become apparent once the tumor reaches about 3cm in diameter. Presenting symptoms in adults are classically headache and visual disturbances, while children often present with growth retardation due to pituitary hypofunction and Growth Hormone deficiency. On physical exam both neurological and general findings may occur. There may be signs suggestive of increased ICP or visual field defects. Also, there could be endocrine signs of hypothyroidism or adrenal insufficiency. Symptoms of hypothyroidism include puffiness, non-pitting edema, slow deep tendon reflexes, and constipation. Adrenal insufficiency can present with symptoms of decreased cortisol, such as hypotension and hypoglycemia, or insufficient aldosterone, characterized by hypovolemia, azotemia, and hyperkalemia, which could lead to cardiac arrhythmias.
â€˘ DDx: Arteriovenous Malformations, Cavernous Sinus Syndrome, Low-Grade Astrocytoma, Migraine headache, Mutliple Sclerosis, Neurosyphilis, Primary CNS Lymphoma
â€˘ Workup: A full workup needs to include an extensive H&P, laboratory studies, and imaging studies. Useful lab tests include endocrinologic studies such as baseline serum electrolytes, serum and urine osmolarity, thyroid studies, morning and evening cortisol levels, Growth Hormone levels, LH/FSH levels. Imaging studies strongly suggest the diagnosis, with the radiologic hallmark of Craniopharyngiomas being the presence of a sellar/suprasellar calcified cyst. CT scan is the most sensitive method to demonstrate such cysts. MRI is most useful in defining the local anatomy, which is required for the surgical approach.
â€˘ Treatment: There are two main treatment options available for Craniopharyngiomas. The first is total gross resection, the second being limited surgery followed by radiotherapy. Gross total surgery is currently the treatment of choice but it does have significant morbidity and mortality, 20% and 12% respectively.
â€˘ Outcomes: Overall, the prognosis for tumors <5cm is excellent for recurrence-free survival. In patients < 20 years of age survival is 99% at 5 yrs. For patients > 65% 5-year survival is much less at only 38%. Larger lesions are more invasive but also have an excellent prognosis. Malignant transformation to squamous carcinoma is very rare and usually occurs after irradiation.