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Introduction Pituicytoma is a rare form of primary benign tumor of the neurohypophysis and infundibulum. There have been 140 reported cases in world literature that could be found in our search. Here we discuss about the presentation, radiological features, treatment, histopathology, and immunohistochemical markers of two cases, along with a brief review of literature. Case 1 A 48-year-old female presented with headache and painless visual loss for 4 years. Examination revealed bitemporal hemianopia and normal fundus. Hormonal profile was normal. Magnetic resonance imaging (MRI) showed 2.6 × 2.8 × 3.3 cm, thin-walled, cystic sellar and suprasellar lesions stretching the optic chiasm superiorly. Endoscopic transnasal, transsphenoidal gross total excision was done. Histopathological examination (HPE) and immunohistochemistry (IHC) were suggestive of pituicytoma. Case 2 A 55-year-old male presented with intermittent headache and vomiting for 3 months. Examination was unremarkable. Hormonal profile was normal. MRI showed lobulated mass of size 1.4 × 1.9 × 2.0 cm, arising from anterior pituitary and extending to the suprasellar cistern. Lesion was hyperintense in T1-weighted and heterointense in T2-weighted images, and Fluid attenuated inversion recovery images (FLAIR) with homogenous contrast enhancement pushed the optic chiasm superiorly. Endoscopic transnasal partial excision of the lesion was done. HPE and IHC were suggestive of pituicytoma. Discussion Total number of cases was 142, of which 71 were males (50%) and 71 were females (50%). Age ranged between 7 and 83 years (mean 49.2, median 48). Brain imaging was available in 110 cases. Size of the lesion varied from 4 to 72 mm (mean 27 mm). Location was either pure sellar (24.3%) or with extension into the suprasellar cistern (34.3%) and/or the cavernous sinuses (7.1%). Lesions in MRI were solid (84%) with few areas of cystic changes, while contrast enhancement of solid portion was in 92% (homogenous in 80% and heterogeneous in 20%) of the cases. One case showed features of hemorrhage while no case showed calcification. Treatment was primarily surgical (120 out of 130 cases): transsphenoidal excision in 70% of the cases and craniotomy and excision in 30%. Preoperative embolization of arterial feeders was done in two cases and postoperative radiation was given in one case. Gross total resection was done in 46.3%, subtotal resection in 40%, partial resection in 12.6%, and biopsy was done in 1.1% of the cases in the study. Follow-up ranged from 2 to 134 months (average 31.2, median 19). Recurrence or regrowth was documented in 23 patients, treatment in 18 patients, and resurgery was done in 12 cases, followed by radiotherapy in 5. In six cases, radiotherapy was used in isolation. Improvement in the visual deficit was seen in 26 patients, and remained unchanged in 3. Among the patients with preoperative endocrine dysfunction, 10 improved while 11 suffered a worsening. Ten patients had new postoperative endocrine alteration. Only one fatal case was registered. Conclusion Pituicytoma is a rare World Health Organization grade I tumor of the sellar and suprasellar region, presenting with varied clinical, radiological, and hormonal features. Histopathology and immunohistochemistry form the mainstay in diagnosis. Surgical excision with transsphenoidal approach is ideal. Prognosis in general is good after surgical resection alone or in conjunction with radiotherapy.

Microneurosurgery made its debut in the early 1960s. It became popular quickly in the medical field and soon became a primary method in neurosurgery, as it improved the efficacy of neurosurgery, reducing surgically related injuries. Over the past five decades, the accumulation of microsurgery experience, improvements in microsurgical techniques, refinement of microinstruments, and advanced preoperative diagnostic imaging have enabled the evolution of microneurosurgical techniques and the further reduction of surgery-related trauma. These advancements have made it possible for neurosurgeons to treat more complicated lesions via smaller craniotomies [35, 60]. Keyhole neurosurgery, a combination of modern microsurgical techniques, preoperative imaging, neuroendoscopy, and the modern concept of minimally invasive surgery, is a technique representing the medical advances from microneurosurgery to minimally invasive neurosurgery [19, 63, 88]. Keyhole neurosurgery is a new, minimally invasive concept of microsurgery based on tailored, targeted, and direct microneurosurgical techniques [26, 70]. With specific anatomic and pathological structures and utilizing the “keyhole effect”, this method is designed precisely as an individualized approach to minimize the anatomic window and expose the lesions adequately, thus reduces unnecessary exploration of the surgical site and brain retraction. The “keyhole” concept involves not only smaller exposures, but also fewer surgery-related complications, the main and more important goal [62]. Pre-calculation of the size of the incision, bone window, and location of the craniotomy is based on the need for only a small dura opening with less brain exposure and retraction and is done in accordance with the principle of “maximal surgical efficiency while minimizing approach-related injury [10,19,30,64].” In general, a 4-cm incision and a cranial bone window of about 2.5 cm in diameter are applied wieldy in the keyhole surgery for deep lesions [74, 79, 87]. Keyhole microsurgery optimizes the cosmetic outcomes. This fact, along with the reduction in surgery-related complications, which improves patient’s acceptance of the surgery. In addition, surgeons can spend more time and focus on treating the lesions, thus achieving maximal surgical effects, shortening hospitalization times, and reducing treatment costs [49, 61, 88]. It has become clear to many of us that despite a growing literature supporting the use of selected keyhole approaches for certain intracranial pathologies, the literature lacks on well-established and standardized practices in this field. Given the importance of developing a collection of standard practices and acceptable indications for these relatively new approaches, we felt that an expert description was timely and important for both guidance about best practices, medicolegal protection, and for defining terms so the literature could be more clearly elaborated in the future. To this end, the International Society on Minimally Invasive Neurosurgery (ISMIN) assembled organized experts in keyhole and minimally invasive surgery in Suzhou, China, in November 2018 from all over the world to compile a summary of the literature and expert opinions and guidance into a single statement. That is intended to improve neurosurgeons’ knowledge of keyhole microsurgical technology, to standardize the operative procedures, and to promote the development of minimally invasive neurosurgery all over the world.