Craniopharyngioma and other cystic epithelial lesions of the sellar region: a review of clinical, imaging, and histopathological relationships.
OBJECT
Cystic epithelial masses of the sellar and parasellar region may be difficult to differentiate on a clinical, imaging, or even histopathological basis. The authors review the developmental relationships and differentiating features of various epithelial lesions of the sellar region.


METHODS
The authors performed a review of the literature to identify previous studies describing the etiological relationships and differentiating features of various cystic sellar lesions, including craniopharyngioma (CP), Rathke cleft cyst, xanthogranuloma, and dermoid and epidermoid cysts.


RESULTS
There is significant evidence in the literature to support a common ectodermal origin of selected sellar and suprasellar cystic lesions, which may account for the overlap of features and transitional states observed in some cases. Research obtained from animal studies and reports of transitional cystic epithelial masses or lesions crossing over from typical to more aggressive pathological subtypes have collectively provided a solid foundation for this theory. Histological features that signify transitional entities beyond simple benign Rathke cleft cysts include squamous metaplasia, stratified squamous epithelium, and ciliated or mucinous goblet cells in squamous-papillary CPs. Several studies have identified key clinical, imaging, and histopathological features that can be used in the differentiation of these lesions.


CONCLUSIONS
The pattern of embryological formation of the hypothalamic-pituitary axis plays a major role in its propensity for developing cystic epithelial lesions. Subsequent inflammatory, metaplastic, and neoplastic processes may promote further progression along the pathological continuum, ranging from benign epithelial cysts to aggressive neoplastic cystic CPs. Selected clinical, imaging, and histopathological features can be used collectively to help differentiate these lesions and assign a formal diagnosis, thus accurately guiding further treatment.