Macroscopic brain gray matter staining: historical protocol overview and neuroanatomy learning applications in second-year medical students.

Macroscopic staining in anatomical samples of the central nervous system is a technique that has been used for decades to achieve better differentiation of multiple gray matter structures, such as the cortex, basal ganglia, and cerebellar nuclei. Staining methods are based on using the different components of the brain, mainly the lipids present in the white matter. These techniques have been progressively forgotten while computer renderings are increasing; however, as a primary exposure to surgical anatomy, stained brain specimens are considered a helpful tool. We aim to summarize different staining techniques, their principles, and their current applications for neuroanatomy learning purposes. In total, four gray matter staining protocol descriptions (Mulligan's, Roberts's, Alston's, and Prussian Blue) were performed, as well as Likert scale surveys of second-year medical students about their perceptions of the stained sections. The results showed that the different macroscopic stains for brain tissue are based on lipid and reactant interactions, intending to increase the white matter (WM) and gray matter (GM) contrast. The search also showed that most staining protocols would take 2 days to develop. Efficient preservation options include submerging the sections in formaldehyde solutions, formaldehyde-free solutions, ethanol, or applying plastination techniques. Based on the student's perspective, the stained slices seem to be a valuable alternative to facilitate the study and identification of the basal ganglia and their relationships with the white matter (from 51.2 to 72% based on the Likert scale) compared with the non-stained sections. In conclusion, macroscopic staining of brain tissue continues to be a valuable tool for comprehensively studying the brain. Further research is needed to determine the efficacy of stained specimens as teaching tools.

Sellar Gangliocytoma: Case Report and Review of an Extremely Rare Tumour.

Sellar gangliocytomas (SGs) are rare, well-differentiated, low-grade neoplasias that commonly present along with a pituitary adenoma (PA). We describe a case of a 52-year-old woman with a 2-year history of headache, body weight increase, and recent onset of arterial hypertension and type 2 diabetes mellitus. Work-up tests revealed a normal hypophyseal profile, except for mild ACTH elevation, and a sellar mass on magnetic resonance imaging (MRI). A diagnosis of an enlarging pituitary macroadenoma was established, and to prevent symptom progression, the tumour was resected. Pathology showed 2 cell populations: ganglion and corticotrope cells. Three years after surgery, the patient no longer had a headache but persisted with arterial hypertension and type 2 diabetes mellitus. A literature review produced 207 cases of SGs. They typically present in women at 40 years of age and the most common clinical presentation are symptoms of acromegaly. Of the documented cases, 74 and 93% were treated with surgery alone or combined treatments (radiotherapy, radiosurgery, or pharmacotherapy), respectively. The majority of deaths associated with a SG came from the first half of the 20th century. In conclusion, this patient presented with a silent SG with likely pituitary hyperplasia. SGs are a challenging diagnosis, have a benign course, and may provide insights into PA tumourigenesis.