Endoscopic biopsy of pineal tumors: two burr hole trans-foramen of Monro approach and endonasal trans-tuber cinereum approach.

INTRODUCTION: The pineal region is a challenging area for neurosurgeons due to its innate anatomical features, such as its deep location, surrounding large draining veins, and adjacent critical neural structures. DISCUSSION: There is a high proportion of malignant tumors in the pineal gland, especially in children, and they are frequently accompanied by obstructive hydrocephalus. These cases require that surgical procedures can make a pathological diagnosis to guide further treatment strategies and immediately resolve increased intracranial pressure. Simultaneous endoscopic third ventriculostomy and biopsy have been regarded as the first-line surgical intervention before establishing a definite treatment plan. However, it is not always successful because various factors affect the surgical procedures, such as the location and extent of the tumor, degree of ventriculomegaly, location and size of the massa intermedia, and size of the foramen of Monro. CONCLUSION: Here, we briefly reviewed the points to be considered in endoscopic biopsy of pineal tumors and introduced an alternative surgical procedure, the endoscopic endonasal trans-tuber cinereum approach, to surmount the anatomical hurdles.

Tuber cinereum proximity to critical major arteries: a morphometric imaging analysis relevant to endoscopic third ventriculostomy.

BACKGROUND: Arterial bleeding in the interpeduncular fossa is a dreaded complication of endoscopic third ventriculostomy (ETV). When the "safe zone" of the tuber cinereum (TC) is fenestrated, the basilar artery tip (BT) or its branches may be encountered below the third ventriclular floor. Major arterial injuries might be avoided by careful preoperative planning. We aimed to establish previously unavailable normal magnetic resonance imaging (MRI) and MR angiographic (MRA) morphometry and configuration of the BT and posterior cerebral artery P1 segments relative to the TC. METHODS: We analyzed images of 82 patients with non-dilated ventricles (mean Evans' index 0.26), and lying in a neutral head position (mean cervico-medullary angle 141°). We cross-referenced axial MRAs with sagittal MRIs to measure distances of BT and P1 segments from the TC, and to classify the location of the BT in the interpeduncular and suprasellar cisterns. We correlated the sagittal areas of these cisterns and patients' ages with the TC-to-artery distances using regression analysis. RESULTS: The BT, right P1 and left P1 segments were a mean 4.9 mm, 5.5 mm, and 5.7 mm respectively from the TC. Seventy-four percent of BTs were anterior to the mammillary bodies. These distances and locations did not correlate with age (mean 53 years) or size of basal cisterns. CONCLUSIONS: The normal BT and P1 segments are anatomically close to the TC and potentially at risk during ETV in adults of all ages. The new morphometric data presented, along with cross-referencing of preoperative multiplanar images, could help reduce vascular complications during ETV.

Precocious puberty produced by an osteolipoma of the tuber cinereum.

Central precocious puberty (CPP) is fairly common in girls. In most girls, the etiology for the CPP is unknown. Among the more rare causes of CPP in girls are central nervous system tumors and hamartomas. Osteolipoma of the tuber cinereum, which is the most commonly diagnosed at autopsy, has been reported as a cause of CPP. We describe an 8-year-old girl with central precocious puberty in whom MRI demonstrated a lesion compatible with osteolipoma. Her symptom was breast development that begun at age 7 years and 9 months. Her case history, laboratory studies and imaging are presented. Her puberty was rapidly progressive. She was treated successfully with a GnRHa (Triptorelin 3.75 mg IM q 4 weeks). Her case brings to the forefront the need to perform an MRI in children with rapidly progressing puberty.

Case Report: Lipoma of the Tuber Cinereum Mimicking a Pituitary Gland Abnormality in a Girl With Central Precocious Puberty.

Introduction: Magnetic Resonance Imaging (MRI) is the best approach to investigate the hypothalamic-pituitary region in children with central precocious puberty (CPP). Routine scanning is controversial in girls aged 6-8 year, due to the overwhelming prevalence of idiopathic forms and unrelated incidentalomas. Cerebral lipomas are rare and accidental findings, not usually expected in CPP. We report a girl with CPP and an unusually shaped posterior pituitary gland on SE-T1w sequences. Case Description: A 7.3-year-old female was referred for breast development started at age 7. Her past medical history and physical examination were unremarkable, apart from the Tanner stage 2 breast. X-ray of the left-hand revealed a bone age 2-years ahead of her chronological age, projecting her adult height prognosis below the mid parental height. LHRH test and pelvic ultrasound were suggestive for CPP. Routine brain MRI sequences, SE T1w and TSE T2w, showed the posterior pituitary bright spot increased in size and stretched upward. The finding was considered as an anatomical variant, in an otherwise normal brain imaging. Patient was started on treatment with GnRH analogue. At a thorough revaluation, imaging overlap with adipose tissue was suspected and a new MRI scan with 3D-fat-suppression T1w-VIBE sequences demonstrated a lipoma of the tuber cinereum, bordering a perfectly normal neurohypophysis. 3D-T2w-SPACE sequences, acquired at first MRI scan, would have provided a more correct interpretation if rightly considered. Conclusion: This is the first evidence, to our knowledge, of a cerebral lipoma mimicking pituitary gland abnormalities. Our experience highlights the importance of considering suprasellar lipomas in the MRI investigation of children with CPP, despite their rarity, should the T1w sequences show an unexpected pituitary shape. 3D-T2w SPACE sequences could be integrated into standard ones, especially when performing MRI routinely, to avoid potential misinterpretations.

Mechanism of tuberothalamic infarction.

BACKGROUND AND PURPOSE: The tuberothalamic artery (TTA), one of the arteries supplying the paramedian thalamic area, is peculiar because it originates from the posterior communicating artery (p-comA), which connects the vertebrobasilar and carotid systems. METHODS: From Stroke Registry, 23 consecutive patients with an acute infarction involving the TTA were selected. We investigated the mechanism of TTA infarction. RESULTS: Fourteen of 23 patients (61%) had coexisting infarctions outside the TTA territory (carotid in three, vertebrobasilar in seven, and both carotid and vertebrobasilar arteries in four patients). Coexisting lesions were most common in the posterior thalamoperforating arterial territory (seven patients). Eleven out of 14 patients (79%) with coexisting lesions had embolic sources from the heart or proximal atherosclerotic arteries, and cardioembolism was the most common mechanism. However, eight of the nine patients with isolated tuberothalamic lesions were classified as small vessel occlusions. More patients with embolic sources had visible p-comA or fetal-type posterior cerebral arteries. The vertebrobasilar arterial system played a more dominant role in developing tuberothalamic infarction than the carotid arterial system. CONCLUSIONS: Isolated TTA infarctions are rare and mostly because of small vessel occlusion. Patients with coexisting infarctions outside TTA territory usually have an embolic source, predominantly vertebral artery atherosclerosis.

Symptomatic osteolipoma of the tuber cinereum masquerading as calcified retroclival mass.

We present a case of symptomatic osteolipoma of the tuber cinereum in a 51 year old male with rapid visual deterioration over several months leading to bilateral visual loss. Preoperatively the lesion masqueraded as a calcified retroclival mass. Intracranial osteolipomas are rare benign lesions that are usually asymptomatic and have an indolent course. Additionally, we discuss our intraoperative findings highlighting the technical challenges encountered along with a review of the English language literature on histologically proven intracranial osteolipomas.

Large neurons in the tuberomammillary nucleus in patients with Parkinson's disease and multiple system atrophy.

To investigate whether the histaminergic neurons degenerate in Parkinson's disease (PD) and multiple system atrophy (MSA), we studied the number of large-sized neurons in the tuberomammillary nucleus in patients with PD, patients with MSA, and age-matched controls. The number of large-sized neurons in the tuberomammillary nucleus in PD patients was not altered compared with controls, and Lewy bodies were rarely present in the tuberomammillary nucleus. In contrast, the number of large-sized neurons in the tuberomammillary nucleus in MSA patients was significantly decreased compared with controls. Thus, the central histaminergic neurons are affected in MSA and preserved in PD.

Lateral hypothalamic demyelination and cachexia in a case of "malignant" multiple sclerosis.

A 41-year old woman had profound weight loss and cachexia as a manifestation of rapidly fatal multiple sclerosis. Demyelinating lesions were present in the lateral hypothalamus. Data from animal experiments have indicated that lateral hypothalamic lesions cause a weight loss associated with a lowering of the regulation level or "set-point" for body weight. This case suggests, therefore, that a rapid decline in the level of maintained body weight in a patient without pituitary disease or general organic disorder, or distinct emotional disorder, may represent a clinical manifestation of tissue injury of the lateral hypothalamus.

MR imaging and spectroscopy of a tuber cinereum hamartoma in a patient with growth hormone deficiency and hypogonadotropic hypogonadism.

To our knowledge, this is the first report of hypogonadotropic hypogonadism, or growth hormone deficiency, in a patient without non-Pallister-Hall syndrome who had hypothalamic hamartoma diagnosed on the basis of MR imaging and MR spectroscopy findings. On short-TE proton MR spectra, the N-acetylaspartate concentration in the hamartoma was lower than that in the thalamus but similar to that in the amygdala. However, myo-inositol concentration was elevated in the hamartoma compared with that in the amygdala and thalamus. This report stresses the advantages of short-TE spectroscopy and demonstrates that regional variations in spectra should be considered when reference structures are used.

Symptomatic osteolipoma of the tuber cinereum. Case report.

The authors present a case of an ossified lipoma located at the tuber cinereum. Intracranial osteolipomas are rare lesions that occur in the region of the tuber cinereum. Almost all reported cases have been incidental autopsy findings. This report, however, involves a young girl who presented with an ovarian cyst and signs of precocious puberty, in whom a typical osteolipoma was surgically removed. This is the first case of hypothalamic osteolipoma presenting with endocrinological disturbances that has been published to date.

Idiopathic isosexual central precocious puberty: magnetic resonance findings in 30 patients.

The purpose of this prospective study was to define the incidence of magnetic resonance imaging (MRI) abnormalities in the brain in patients with idiopathic central precocious puberty without any additional neurological signs and symptoms, and to evaluate the routine use of gadolinium contrast in these patients. 30 patients (29 girls, one boy; age range 1.9-11.9 years) with idiopathic central precocious puberty were studied. MRI of the brain in axial, coronal and sagittal planes was performed before and after administration of gadopentetate dimeglumine, with special attention to the region of the third ventricle. There are three major findings: (1) the height of the pituitary gland is increased up to adult size compared with normal individuals; (2) in four patients (13%) major structural abnormalities were found; three hamartomas of the tuber cinereum and one gliomatous process extending from the chiasm to the optic tract; and (3) the routine use of gadopentetate dimeglumine did not reveal new abnormalities although the lack of enhancement made a positive contribution to diagnostic certainty. We conclude that contrast enhanced MR examination is a safe and reliable method for the exclusion of abnormalities in children with precocious puberty and for the follow-up of those patients in whom abnormalities are present.

Symptomatic osteolipoma of the tuber cinereum.

Intracranial osteolipomas are rare lesions which occur in the region of the tuber cinereum. All cases reported to date have been incidental autopsy findings. We describe a patient who presented with a variety of neurological symptoms and had a typical osteolipoma surgically removed.

Osteolipomas of the tuber cinereum.

Osteolipomas of the tuber cinereum traditionally have been classified as meningeal lipomas that are located at the tuber cinereum. Examination of two cases and a review of 22 others found in the literature show that these lesions exhibit a remarkable consistency in their size and in their location between the corpora mamillaria and the pituitary stalk, and that approximately half of them contain a well-organized bone spherule with a central marrow space. These aspects differ from the features of meningeal lipomas in general; reasons are given for considering that the osteolipomas are displaced elements of the mesenchyme encompassing walls of the craniopharyngeal duct.

The lipoma of tuber cinereum.

Two cases of lipoma of the tuber cinereum, unexpectedly discovered in the course of autopsy examination, are reported. Each case was thoroughly investigated by serial sectioning of both the diencephalic floor and the tumor. Some peculiar findings observed and a complete survey of the literature revealed that such a growth may be considered an incomplete benign mesenchymoma, i.e., a mixed tumor of mesenchymal derivates, according to Stout (14). The error in development, consisting in the inclusion of embryonal germs of primitive meninx into the nervous system, may occur early during the third month of intrauterine life, at the time of the formation of the primitive septa.

Changes in the nucleolar organizer regions in the tuberomammillar region after dehydration.

The existence of efferent connections between tuberomammillary (TM) and the supraoptic (SON) nuclei led us to study the morphological changes at these levels during dehydration induced in rats by repeated administration of hypertonic saline. The dehydration effects are evaluated by three parameters: nucleus area, argyrophilic nucleolar organizer regions (Ag-NOR) area, and mean number of Ag-NORs. These parameters reflect the level of transcriptional activity of the rRNA genes, which in turn is closely related to the protein synthesis activity of the cell. The technique used is argyrophilic staining which labels the nucleolar organizer regions (NORs) of the nucleoli in the neurons and their area, permitting their quantification with an image analysis system. The statistical analysis reflects the sensitivity to dehydration of these structures at TM level. Our results support the regulatory role of vasopressin secretion by SON through the histaminergic pathways arising from TM in rat dehydration processes.