Craniopharyngioma

Craniopharyngioma
Craniopharyngiomas arise from epithelial remnants of the Rathke pouch and are typically found in the suprasellar region in children or adolescents. They account for <5% of all CNS neoplasms in adults. They are slowly growing tumors that often have solid and cystic components, the latter filled with lipoid, cholesterol-laden (โ€œcrankcase oilโ€) fluid. Although appearing well encapsulated, craniopharyngiomas typically demonstrate invaginations into adjacent brain and may provoke a vigorous glial reaction.
The cystic nature of craniopharyngiomas is usually evident on CT and MRI and helps distinguish these tumors from other base of skull lesions and pituitary adenomas. The solid portion is often calcified and enhancing, whereas the cystic portion typically demonstrates a thin rim of enhancement. The finding of multiple cysts of varying intensity on T1- and T2-weighted MRI is characteristic of

Intrasellar lesions may compress the pituitary and hypothalamus, producing hormonal abnormalities, especially antidiuretic and growth hormone deficits. Prechiasmal lesions may compress the optic pathway, leading to visual field cuts or decreased central visual acuity. Retrochiasmal lesions may grow into the third ventricle and cause hydrocephalus or compress the optic tracts. Craniopharyngiomas can occasionally reach enormous size and produce neurologic impairment by direct impingement on brain parenchyma. Surgical decompression is the optimal treatment for rapid symptom relief. However, the location, proximity, and adhesiveness of the tumor to adjacent structures often preclude complete resection.
Treatment
A discussion of craniopharyngioma in the pediatric context is provided in Chapter 82, Management options include complete resection, subtotal resection alone, or subtotal resection or biopsy followed by postoperative radiotherapy.
Complete surgical resection, which is applicable only to a minority of patients, is associated with local control and long-term survival in 70% to 90% of patients (17). However, aggressive resection may be associated with significant morbidity, with up to a 10% incidence of perioperative mortality and up to 30% severe morbidity, especially diabetes insipidus or other endocrine deficits, visual impairment, obesity, and memory impairment.
Partial resection or cyst aspiration and biopsy rapidly relieve local compressive symptoms and have less operative morbidity but are associated with eventual tumor progression in most cases. Long-term survival and local control are achieved only in approximately 30% of patients. In contrast to aggressive resections, subtotal resections carry a mortality of about 1%.
With a limited surgical procedure (partial resection or cyst aspiration plus biopsy) followed by radiotherapy local control and survival rates are nearly equivalent to those achieved with complete resection, with survival rates of 89% and 77% at 5 and 10 years, respectively, as compared with 53% to 37% for patients who have had subtotal resection alone. Typically, doses of 50 to 54 Gy in 25 to 30 fractions (1.8 Gy) over 6 weeks are delivered to the preoperative tumor volume with a 1- to 1.5-cm margin depending on the accuracy of the imaging used for planning and the reproducibility of the treatment setup. In patients with compressive symptoms, surgical decompression before irradiation is essential because the tumor typically responds slowly to radiotherapy, and radiation-induced edema may worsen compressive symptoms.
With these dose recommendations (i.e., 1.8-Gy fractions to 50 to 54 Gy), the risk of visual impairment is very low (1% and 1.5%). In a retrospective analysis of patients treated with 51.3 to 70 Gy, a higher incidence of radiation-related complications was seen in those who received more than 60 Gy (with an actuarial incidence of optic neuropathy of 30% and brain necrosis of 12.5%), without any concomitant improvement in tumor control (72).
Radiotherapy may be given as salvage rather than immediately after subtotal resection. In a series of 76 patients treated at the University of Pennsylvania, long-term survival rates were equivalent (232). In another series radiotherapy given at recurrence yielded a 10-year progression-free survival rate of >70% (108). Recurrences occur from 3 to 192 months (median 12 months) after subtotal resection so that close surveillance is necessary during the first years following incomplete resection.
Other modalities used in the treatment of craniopharyngioma have included intralesional bleomycin and radioactive colloid instillations for cystic tumors. Radiosurgery may be useful in ablating small residual or recurrent tumors (118).
Evidence-Based Treatment Summary
Surgical resection is recommended, when feasible.
The use of postoperative radiotherapy has not been tested in prospective trials, but reduces the risk of recurrence and improves survival in incompletely resected tumors. Cyst decompression and biopsy followed by radiotherapy may be an acceptable treatment for patients for whom resection is not considered feasible.
Intracavitary bleomycin or radiocolloids may be useful in cystic tumors.