Discussion
The rarity of these non-endocrine pituitary tumors and relatively small studies in the literature have led to a somewhat conflicting understanding of these tumors and disparate treatment recommendations. Like others in the literature, the currently study is limited by a small number of patients in each tumor category, as well as the retrospective nature of data collection.
In terms of immunohistologic findings, SCOs have been shown to display positive S100 and EMA staining patterns13, which we have also found in our dataset. However, we feel EMA should not be thought of as a method to distinguish SCOs from other lesions6, since PCTs were also positive for EMA staining. Additionally, we found that TTF-1 was expressed in all eleven of our tumors, confirming their histogenetic similarity and likely shared lineage6. Outside of TTF-1 staining, a major limitation of our histologic results is that many stains were not performed on all tumors.
Another observation worthy of discussion revolves around the locations of these tumors. While the literature describes PCTs as purely intrasellar7,8, we found that PCTs may be found in suprasellar or infundibular regions as well. Moreover, our results showed that GCTs were never exclusively found in the intrasellar region, which has also been described by Cohen-Gadol et al15, potentially identifying a reason to exclude these lesions from the differential diagnosis of a purely intrasellar mass. An interesting note regarding the locations of SCOs is that we had one case of a purely intrasellar lesion, showing that it is possible for SCOs to be isolated within the intrasellar region, rather than both intra- and suprasellar7.
Our case series suggests that preoperative endocrine abnormalities, such as hypopituitarism, may be more common in SCOs compared to other tumors, which aligns well with what is currently shown in the literature16. Despite this, we did not find any new or worsening endocrine abnormalities in SCOs, postoperatively.
As far as surgical management and follow-up is concerned, PCTs and SCOs are thought to be highly vascular15,16. The possibility of a massive bleed during surgery has been suggested by some to lead to subtotal resection, perhaps predisposing to recurrence of these tumors \cite{Wolfe2008}\cite{Pirayesh2012}\cite{Zygourakis2015}. However, our series showed that all eleven of the tumors, regardless of classification, had a gross total resection without encountering significant blood loss due to tumor vascularity. Furthermore, the high vascularity of these tumors invited support from some groups for a Sylvian, as opposed to an endoscopic, approach in order to preserve vascular integrity17,18; however, we were able to utilize the endoscopic approach safely for these tumors, including for an infundibular GCT case. With a mean follow up of 4.72 ± 3.65 years and no recurrences, we believe that gross total resection is key for management of these tumors.