In this article Micko et al. 1 discuss dumbbell-shaped pituitary adenomas and their relationship with the diaphragma sellae.It is unfortunate that the authors seem to have ignored the articles that my colleagues and I have published on the subject. [2]][4][5] In our several published articles on this topic, my colleagues and I have discussed the pattern of growth of pituitary tumors, particularly those that acquire a giant size, and their relationship with the dural layers of the region that includes the diaphragma sellae. [2]3][4][5] My coauthors and I reported for the first time in the literature, to our knowledge, that in a large majority of such dumbbell-shaped tumors the diaphragma sellae "dura" is elevated on the dome of the tumor. 2,3 Previously the understanding was that pituitary tumors emerged out of the aperture of the diaphragma sellae that is normally occupied by the pituitary stalk.The elevated diaphragma sellae may be thinned out in larger tumors and the thickness and consistency may resemble that of the arachnoid membrane.This anatomical observation has major surgical implications, because the elevated dural layer of the diaphragma forms a distinct layer of compartmentalization and a reliable barrier for resection of the tumor away from the arteries of the circle of Willis, optic chiasma, and other critical neural structures.The diaphragma sellae falls into the surgical field at the end of tumor resection, signaling the radicality of resection.My colleagues and I have classified giant pituitary tumors into 4 grades. [2]3][4][5] Grade 1 pituitary tumors were those that remained confined to the sella and subdiaphragmatic space and did not invade into the cavernous sinus.Such tumors formed a majority of giant pituitary tumors.Although transgression of the medial dural wall of the cavernous sinus was a more frequent event in tumors of this grade, transgression of the diaphragma sellae was infrequent.Grade 4 pituitary tumors were those that extended into the supradiaphragmatic space, were locat-ed in the subarachnoid space, and had intimate relationships with arteries of the circle of Willis.The exact site of communication of the sellar and supradiaphragmatic part of the tumor could not be confirmed.However, transgression from the diaphragma sellae opening appeared to be infrequent.We observed that radical resection of grade 4 pituitary tumors was technically difficult and was fraught with the possibility of postoperative hemorrhagic complications.We also observed that grade 4 giant pituitary tumors were inherently more aggressive in nature.Recurrences of these tumors were high, and such tumors merited consideration of postoperative upfront radiation treatment.This understanding regarding the relationship of pituitary tumors with the diaphragma sellae has had a significant impact in the shifting of neurosurgeon preference toward transsphenoidal surgery when transcranial surgery was previously the more frequently chosen approach for pituitary tumors with suprasellar extension.