Operative approaches to the pineal region tumors

Pediatric Pineal Region Tumors: Special Reference to Posterior Interhemispheric Trans-Tentorial Approach

Pediatric pineal region tumors consist of tumors of pineal gland origin and parapineal origin. The former are comprised of germ cell tumor (GCT) and pineal parenchymal tumor. The latter originate from the surrounding neural structures, such as the midbrain and thalamus; thus, they are often benign gliomas during childhood. Pineal region tumors often cause obstructive hydrocephalus, which is the main cause of presenting symptoms. Advanced imaging discloses precise location and extension of the tumor and associated anomalies such as hydrocephalous, dissemination, hemorrhage, etc. Hydrocephalus has been managed with CSF diversion, mostly using an endoscopic third ventriculostomy. Because of different treatment paradigms for each tumor type, histological confirmation is needed either through biopsy, tumor markers for GCTs, and/or surgical resection sampling. Radical resection of these tumors remains a challenge due to their deep-seated location and involvement of delicate neural and vascular structures. Comparison of common craniotomy approaches, occipital transtentorial (OT) and infratentorial supracerebellar (ITSC), is reviewed for their advantages and disadvantages. Surgical area exposure and blind spots are important factors for successful tumor removal. The surgical techniques and nuances that the author employs for tumor resection via a posterior interhemispheric transtentorial approach are presented.

Quality of life following surgical treatment of lesions within the pineal region

OBJECTIVEPineal region tumors are a rare and heterogeneous group of lesions. The optimal therapeutic approach is currently a topic of controversy, particularly in light of the potential operative risks and complications. The potential beneficial effects of surgery have already been described, but information about neurological outcome and, in particular, health-related quality of life (HRQOL) is still lacking in the literature. The aim of this study was to assess the therapeutic effect of resection of pineal region lesions, emphasizing grade of tumor resection, neurological outcome, quality of life, and the necessity of additional shunt procedures.METHODSThe authors performed a prospective study of HRQOL in 32 patients who had undergone surgical treatment of lesions in the pineal region (20 tumors and 12 cysts) between 2008 and 2014. All patients had at least 6 months of follow-up, with reexamination including standardized neurological assessment, an evaluation of dependency using the modified Rankin Scale, and an evaluation of HRQOL. The authors retrospectively examined patient charts and collected information regarding imaging studies, neurological status prior to surgery, surgical strategies used, any complications, and histological diagnoses.RESULTSIn this study, there was no surgery-associated mortality or major morbidity. Permanent minor morbidity was reported for 4 patients (13%). Comparing pre- and postoperative neurological symptoms, 75% of tumor patients had either complete resolution or improvement of preoperative symptoms; symptoms were unchanged in 10% of tumor patients and deteriorated in 15%. In patients with pineal cysts, long-term follow-up showed that 42% of patients were free of any symptoms and 58% experienced improvement of their preoperative symptoms. These outcomes were also reflected in the modified Rankin Scale scores, which demonstrated significant improvement following resection of pineal region lesions. Furthermore, significant improvements in HRQOL scores occurred in global health status, in all functional scales, and in pain, nausea and vomiting, fatigue, and insomnia (p < 0.0001). Moreover, a significant reduction in the necessity for permanent shunt procedures was observed after gross-total tumor resection compared with subtotal resection (p = 0.035) of pineal cysts.CONCLUSIONSDespite potential risks, (radical) surgery is a highly effective and safe treatment option for pineal region lesions and should be considered for the majority of patients.

Microsurgical resection of tumors of the lateral and third ventricles: operative corridors for difficult-to-reach lesions

Tumors of the lateral and third ventricles are cradled on all sides by vital vascular and eloquent neural structures. Microsurgical resection, which always requires attentive planning, plays a critical role in the contemporary management of these lesions. This article provides an overview of the open microsurgical approaches to the region highlighting key clinical perspectives.

Mapping motor representations in the human cerebellum

The cerebellum is a major motor structure. However, in humans, its efferent topographical organization remains controversial and indirectly inferred from neuroimaging and animal studies. Even central questions such as 'Can we evoke limb movements by stimulating the cerebellar cortex?' have no clear answer. To address this issue, we electrically stimulated the posterior cerebellum of 20 human patients undergoing surgery for tumours located outside this structure (e.g. pineal gland, quadrigeminal plate). Stimulation, delivered at a 60-Hz frequency for 2 s, evoked focal (single-joint) ipsilateral movements. Different regions were associated with the production of head (vermal lobule VI), face/mouth (hemispheric lobule VI) and lower-limb (hemispheric lobules VIIb-IX) responses. Upper-limb representations were more widely distributed. They intermingled with face/mouth representations in the superior posterior cerebellum (hemispheric lobule VI) and lower-limb representations in the inferior posterior cerebellum (hemispheric lobules VIIb-IX). No intra- or inter-limb somatotopy was found in these areas. Functionally, upper-limb (face/mouth movements) and upper limb-lower limb postural coordinations are major elements of our motor repertoire. Representation of these pairs of segments in common regions might favour the production of integrated motor behaviours. The intermediate region of the posterior cerebellum (hemispheric lobule VII and vermal lobules VII-VIII) was mostly silent. Latency results in conjunction with previous electrophysiological evidence in animals suggest that electrically evoked motor responses were not mediated by a cortical route but rather by brainstem structures. The potential role of this descending efferent pathway for fine motor control is discussed.

The long-term postsurgical prognosis of patients with pineoblastoma

BACKGROUND

For this report, the authors comprehensively summarized the existing literature on patients with pineoblastoma and identified the variables and treatments that had an impact patient on outcomes.

METHODS

A comprehensive search identified 109 studies that collectively described the outcomes of patients with pineoblastoma. Individual patient data were classified based on treatment and were subjected to univariate comparisons. Cox regression analysis included comparisons of survival outcomes controlling for age, extent of resection, and treatment group, and between-group survival comparisons were performed using the Kendall tau (rank correlation) statistic.

RESULTS

Two hundred ninety-nine patients met inclusion criteria. The overall survival rate was 54% (175 of 299 patients) at a mean follow-up of 31 ± 1.9 months (range, 1-159 months). The analyses demonstrated a markedly worse prognosis for children aged ≤ 5 years compared with older patients (5-year survival rate: 15% for children aged ≤ 5 years vs 57% for children aged ≥ 5 years; log-rank P < .00001). In addition, a graded increase in survival was observed with increasing degrees of resection (5-year survival rate: 84% for patients who underwent gross total resection vs 53% for patients who underwent subtotal resection vs 29% for patients who underwent debulking; log-rank P < .0001). Multivariate analysis indicated that not achieving gross total resection markedly worsened patient survival (subtotal resection: hazard ratio, 6.47; 95% confidence interval, 2.3-19; P = .001. debulking: hazard ratio, 9.27; 95% confidence interval, 3.2-27; P < .0001).

CONCLUSIONS

The current findings emphasize the importance of aggressive surgical resection in the treatment of pineoblastoma. In addition, the authors conclude that clinical trials should not mix young patients with older patients or patients who undergo subtotal resection with patients who undergo gross total resection, because such heterogeneity may alter the variability of responses to treatment and reduce the likelihood of success.

Endoscopic biopsy of brain tumors in children: diagnostic success and utility in guiding treatment strategies

OBJECT

Endoscopic biopsy is an important minimally invasive method of diagnosis in the initial management of lesions in children with intraventricular and periventricular tumors. The procedure can be performed in conjunction with CSF-diverting procedures for obstructive hydrocephalus. The authors present their single-institution experience in a predominantly pediatric series with respect to diagnostic efficacy, utility in guiding treatment plans, and safety.

METHODS

A retrospective review was conducted in a consecutive series of patients who underwent endoscopic biopsy of brain tumors during a 13-year period.

RESULTS

There were 33 endoscopic biopsies in 31 patients (16 males and 15 females). The average age of the patients was 11.3 years, with a mean follow-up duration of 2.4 years. The majority of biopsies were performed in conjunction with CSF-diverting procedures, such as endoscopic third ventriculostomy or fenestration of the septum pellucidum. Overall, 23 (70%) of 33 biopsies were diagnostic, with results that directed subsequent treatment. When stratified by tumor location, biopsy samples obtained in the lateral ventricle or pineal region were more favorable toward a successful diagnosis than those in the thalamus or tectal region. In 4 cases, elevated CSF tumor marker levels led to modification of the diagnosis and appropriate adjustment of treatment. The endoscopic third ventriculostomy success rate was 82.4%. There were 2 major complications (6.1%), which resulted in neurological deficits. There were no procedure-related deaths.

CONCLUSIONS

Endoscopic biopsy is an effective means of diagnosis of brain tumors in children. The diagnostic power may be more favorable with tumors in the lateral ventricle or pineal region. Collection of CSF during the procedure for tumor marker analysis is an integral component of diagnosis.

Pure pineal germinomas: analysis of gender incidence

OBJECTIVE

Pure pineal germinomas have been rarely reported in girls. Gender incidence and differences of pure pineal germinomas are not well known. The authors report a series of pure pineal germinoma and its gender characteristic is reviewed.

METHODS AND RESULTS

Of a total of 50 germ cell tumors operated on between 1988 and 2004 we found 26 cases (median age at diagnosis, 12 years) of pineal germ cell tumors. Of these, 14 cases (male/female ratio: 13/1) were pure pineal germinomas, and 12 cases (male/female ratio: 12/0) were non-germinoma germ cell tumors. In pure pineal germinomas, the main clinical presentations were intracranial hypertension and cranial nerve dysfunction. Imaging studies disclosed a homogeneous type of tumor (n = 10) and associated hydrocephalus (n = 6). Cases were managed with biopsy and subsequent radiation therapy and chemotherapy. After a follow up of 10 years, pure germinoma cases have no neurological deficits and tumor recurrence. The literature on gender incidence of pure pineal germinomas is analyzed and possible causes are discussed.

CONCLUSIONS

Although rare, pure pineal germinoma can be found in female subjects. On the basis of the literature review, the male/female ratio in cases of pure pineal germinoma is between 5:1 and 22:1 (mean 14:1). In our series, the male/female ratio was 13:1.

Pineal cysts in childhood

INTRODUCTION

Little is known about the incidence and symptomatology of pineal cysts in children. Until now, the proper management of this group of patients has not been established.

PURPOSE

The purpose of this study was to evaluate the epidemiological and clinical features of pineal cysts in children and adolescents and to try to find guidelines for their management.

METHODS AND RESULTS

We analyzed 24 patients (17 girls, mean age 9, and 7 boys, mean age 14) with pineal cysts found as the only pathology on MRI. Six patients were treated surgically (excision of the cysts via a supracerebellar-infratentorial approach) because of the progression of neurological symptoms or the enlargement of the cyst at follow-up. In this group of patients, no surgery-related complications were noted, nor was residual cyst observed on postoperative MRI. In 4 cases, histological examination revealed simple cysts, but in 2 cases pineocytomas were diagnosed. Preoperative symptoms disappeared except light headache in 2 cases and in 1 case no improvement was obtained. The remaining 18 patients had a mean follow-up of 38 months (range 24-60 months). None of the cysts diminished or collapsed. We also measured the circadian pattern of melatonin secretion as well as beta-HCG and AFP levels in serum before surgery. We found very high night levels of melatonin in both of the patients with pineocytomas, while the patients with pineal cysts showed normal or depressed melatonin secretion profile.

CONCLUSION

We concluded that though most pineal cysts were clinically benign they should be followed up for many years. If the cyst grows larger in follow-up MRI study and neurological symptoms are progressive, surgical treatment should be performed. In the authors' opinion, one of the markers discriminating benign and neoplastic lesions may be melatonin.