Reply:

We have read the explicit letter from Pascual et al entitled “Topographic Diagnosis of Papillary Craniopharyngiomas: The Need for an Accurate MRI-Surgical Correlation,” which emphasized the thorough anatomic and pathologic aspects of papillary craniopharyngiomas (PCPs). We are grateful for the valuable comments about our article.

The pars tuberalis partly joins the diencephalic floor during the seventh week of embryo development and finally covers the pituitary stalk in adults.^1,2 In PCPs, the metaplastic tumorigenesis from epithelial nests at the pars tuberalis grows along the infundibulotuberal region, with variable degrees of adherence to the third ventricular floor and hypothalamus was proposed. In our series, most of the PCPs were classified as not strictly the intraventricular or extraventricular type, and fewer tumors were at the strictly intraventricular or purely sella/suprasellar locations. However, precise differentiation between the PCPs of infundibulotuberal origins and those developing primarily from the third ventricular floor with tight adherence to the hypothalamus might have been difficult in previous studies.^3,4

For the patient in Fig 1, partial removal of the tumor was performed via a transsphenoidal approach. Moreover, the residual tumor attached to the optic tract was subsequently treated by radiosurgery. For the patient in Fig 2, the tumor was seen in the foramen of Monro after endoscopic fenestration of the septum pellucidum during surgical biopsy. In addition, the tumor underwent radiosurgery to minimize the risk of hypothalamic injury. Indeed, the use of not strictly intraventricular or infundibulotuberal PCPs may have more precisely described the location of suprasellar PCPs in Figs 1 and 2 in the article.

However, we have the following concern about this topographic classification⁴ in our clinical practice: It is based on a neurosurgical approach to craniopharyngiomas and is not easily applied to the daily neuroimaging practice for diverse suprasellar lesions. Not all cases of PCPs were diagnosed preoperatively and had the benefit of this topographic classification. For example, this classification provides little help for our diagnosis and management of suprasellar germ cell tumors. The purpose of our study was to make a pretreatment diagnosis of these 2 tumors, without focusing on the surgical approach. The term “suprasellar” is widely used for describing the lesions located between the diaphragm sella and the lower third ventricle by most neurosurgeons and neuroradiologists. Thus, we favor the use of “suprasellar” as a clear and simple term for communication.

• © 2015 by American Journal of Neuroradiology