Craniopharyngioma is an uncommon benign tumor, accounting for 2 to 5% of all intracranial neoplasms.1 Distribution by age is bimodal, with the peak incidence in children at 5 to 14 years of age and in adults at 65 to 74 years of age, with an incidence of 0.14 to 2 per 100,000.^2,3 Although total surgical removal is the aim of the treatment, craniopharyngioma is a difficult tumor to excise completely. Morbidity from an intrapial tumor adherent to the pituitary stalk, hypothalamus, and anterior cerebral vessels has always dictated the completeness of resection. Tumor involvement of these structures combined with poor surgical access, limited instrumentation for sharp dissection, and limited visualization of the anatomical relationships has often hindered dissection regardless of the approach. The use of endoscopes in surgery for these lesions has been particularly successful, allowing minimal operative morbidity, direct access to pathology, and detailed visual assessment of anatomy and resection limits (Harvey laryngoscope). For craniopharyngioma, effective and safe treatment of lesions involving the skull base is still a challenging problem.

Debate exists regarding the histologic description of craniopharyngiomas. Currently, three theories are widely accepted, and from these, the adamantinomatous, squamous papillary, and mixed variants have been derived. They are as follows:

•  Embryogenetic theory: the adamantinomatous type (“adamantinoma”) arises from epithelial remnants of the Rathke pouch or the precursors to the adenohypophysis and infundibulum migrate. Rests can occur from the pharynx to the sella turcica and third ventricle.

•  Metaplastic theory: the squamous papillary type results secondary to metaplasia of squamous epithelial cell rests that arise from squamous cell nests of the pituitary stalk and pars distalis junction.

•  Variant of midline congenital cyst: the variant is a midline congenital tumor not fundamentally different from an epidermoid cyst.

Craniopharyngiomas are usually composed of both solid and cystic components. Cyst walls are lined with stratified squamous epithelium with pearly keratin formations. An outer layer is columnar epithelium. Calcifications occur 90% of children and 40% in adults. A “motor oil” description is often given to the cystic fluid.

Subfrontal and pterional craniotomies have been the traditional approaches to extensive craniopharyngioma with suprasellar extension.⁴ The transsphenoidal route had been previously reserved for purely intrasellar tumors. The extended transsphenoidal transplanum endoscopic⁵ approach may benefit patients with extensive craniopharyngioma (Fig. 19.1), facilitating direct access to pathology, minimizing brain retraction, and reducing manipulation of the optic chiasm, the hospital stay,⁶ and morbidity.⁷

Morbidity from the open approaches may be significant, especially when surgical resection is subtotal. The balance of surgical morbidity and long-term control is a decision for the patient and the operative team. Karavitaki et al⁸ recently reviewed the literature on the long-term outcomes in craniopharyngioma. Accepted 10-year recurrence-free survival rates were 74 to 81% after gross total resection, 41 to 42% after partial removal, and 83 to 90% after surgery (defined as partial or minimal resection) and radiotherapy. The aggressiveness of craniopharyngioma in adults compared with children has been debated. There appears to be little evidence supporting a substantial difference in behavior from larger cohorts.8–10

The extended transsphenoidal approach has been described with microsurgical dissection,^11–17 and extensive nonadenomatous tumors have been managed with these techniques.¹³ The use of an extended sellar opening by removing the sphenoid planum and tuberculum sellae is described in these series.¹³ This route is often the first option even for suprasellar lesions.¹⁷ Transsphenoidal approaches have gained wide acceptance because they offer direct access to the tumor site and avoid the morbidity of transcraniectomy surgery.¹⁷ Subsequently, the transsphenoidal approach has evolved to a totally endoscopic transnasal surgery.¹⁸ A large transnasal craniectomy is not hampered by a long narrow surgical corridor, which previously combined both vision and surgical instruments (Fig. 19.2). Visualization can be superior with an endoscopic approach compared with the microsurgical access.¹⁹

Indications and Advantages

Broadly, the goals of transnasal craniectomy for craniopharyngioma should include the following:

•  Removal of disease and prevention of regrowth

•  Relief of hydrocephalus

•  Decompression of the optic nerve and chiasm

•  Minimal functional loss

  o Vision

  o Other cranial nerve integrity

  o Pituitary/hypothalamic function

  o Orbital function