Surgical treatment of symptomatic pineal cysts without hydrocephalus-meta-analysis of the published literature

Lack of inflammation or immune response in cyst tissue of patients with symptomatic non-hydrocephalic pineal cysts

Pineal cysts are frequently encountered as incidental findings in magnetic resonance imaging, usually devoid of symptoms, yet some patients exhibit symptomatic manifestations possibly associated with the cyst, even in the absence of hydrocephalus. The etiology of these symptoms remains contentious. This study aims to investigate the presence of lymphatic endothelial cell (LEC) markers and indications of inflammation or immune response within the pineal cysts of patients experiencing symptomatic non-hydrocephalic presentations. Eight patients who underwent surgical excision of their cysts were included in the study. Immunohistochemistry was utilized to assess the expression of LYVE-1, PDPN, and VEGFR3 as LEC markers, alongside IL-6 and CD3 for indications of inflammation or immune activity. Our analysis revealed an absence of inflammatory markers or immune response. However, a distinct expression of VEGFR3 was observed, likely localized to neurons within the pineal cyst tissue. We propose that these VEGFR3+ neurons within the pineal cyst may contribute to the headache symptoms reported by these patients. Further investigations are warranted to substantiate this hypothesis.

Prevalence of pineal cysts in healthy individuals: Emphasis on size, morphology and pineal recess crowding

The present study aimed to determine prevalence of non-hydrocephalic pineal cysts of different size and morphology in healthy individuals. In a cohort of healthy individuals who as part of research volunteered to undergo magnetic resonance imaging (MRI) of the brain, we performed a systematic search for occurrence of pineal cysts of different sizes, morphology and evidence of crowding of the pineal recess. Degree of crowding in the pineal recess was estimated by the imaging biomarkers anterior-posterior diameter and cyst-tectum-splenium (CTS) ratio at midsagittal MRI. The study included a cohort of 994 healthy individuals, aged 47.0 ± 21.1 years in whom a pineal cyst was demonstrated in 337/994 (37.5%) individuals. A small cyst within a mainly solid gland was observed in 252/994 (25.4%) subjects and a mainly cystic gland in121/994 (12.2%). The pineal cysts were more frequent in women than men, and were associated with age, though not with reduced prevalence in aged individuals, as previously reported. Cysts with maximum anterior-posterior diameter ≥ 10 mm were seen in 51/994 (5.1%) individuals, and with CTS ratio ≥ 0.9 in 16/994 (1.6%) individuals. The occurrence of pineal cysts is frequent and is seen more frequently in women. It usually presents as a small cyst in a predominantly solid gland; however, pineal cysts causing crowding of the pineal recess with a CTS ratio ≥ 0.9 was seen in merely 1.6% of participants.

Physiological alterations of pineal recess crowding in symptomatic non-hydrocephalic pineal cysts

Pineal cysts are prevalent in the population. Due to more widespread use of magnetic resonance imaging, an increasing number of symptomatic patients with non-hydrocephalic pineal cysts are referred to neurologists and neurosurgeons. Currently, there is no generally accepted theoretical framework for linking symptoms to a pineal cyst. We have previously suggested that cyst-induced crowding of the pineal recess may affect venous runoff from the deep cerebral veins crossing the cyst. However, evidence underpinning this hypothesis is sparse. In the present study, we asked whether crowding of the pineal recess without imaging signs of hydrocephalus may be accompanied with alterations in blood flow of the internal cerebral veins, cerebrospinal fluid flow in the Sylvian aqueduct and cerebrospinal fluid-mediated tracer clearance from the brain along extravascular pathways (referred to as glymphatic function). This prospective, observational study included symptomatic individuals with non-hydrocephalic pineal cysts who underwent a standardized magnetic resonance imaging protocol (n = 25): Eleven patients were treated surgically with craniotomy and cyst extirpation and 14 individuals were managed conservatively without surgery. Our findings suggest that cyst-induced crowding of the pineal recess may have brain-wide effects: (i) There was a significant negative correlation between degree of crowding within the pineal recess and change in maximum venous flow velocity at the cyst, and a significant positive correlation between maximum venous flow velocity change at the cyst and net cerebrospinal fluid flow in the Sylvian aqueduct; (ii) increased degree of crowding in the pineal recess was accompanied by significantly impaired glymphatic enrichment in the cerebral cortex and subcortical white matter, indicative of a brain-wide effect in this cohort who also reported markedly impaired subjective sleep quality; (iii) there was a significant negative correlation between the apparent diffusion coefficient (suggestive of interstitial water content) within the thalamus and glymphatic enrichment of tracer and (iv) pineal recess crowding associated with symptoms. Comparison of the surgical cases [in whom 10/11 (91%) reported marked clinical improvement at follow-up] and the conservatively managed cases [in whom 1/14 (7%) reported marked clinical improvement at follow-up] showed differences in pre-treatment glymphatic tracer enrichment as well as differences in tracer enrichment in subarachnoid cerebrospinal fluid spaces. Taken together, we interpret these observations to support the hypothesis that cyst-induced crowding of the pineal recess without hydrocephalus may alter blood flow of the internal cerebral veins and cerebrospinal fluid flow and even cause brain-wide impairment of glymphatic transport with possible implications for cerebrospinal fluid transport of trophic factors such as melatonin.

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.

Pineal cyst management: A single-institution experience spanning two decades

Background:

Pineal cysts (PCs) are benign lesions commonly found on intracranial imaging. Despite their high prevalence, there is no clear consensus on the most appropriate management of patients with PCs, especially those with symptomatic nonhydrocephalic cysts.

Methods:

A retrospective analysis was performed on 142 patients with PCs (103 surgical cases and 39 conservatively managed cases). Data were examined, including clinical presentation, imaging findings, ophthalmological status, natural course, postoperative outcomes, and complications.

Results:

Surgical group: the most common symptom was headache (92%), followed by signs of intracranial hypertension due to hydrocephalus (22%). New radiological feature of PCs was found in 11 patients. From 71 patients with long-term follow-up, headache completely resolved in 44 (62%) patients; marked improvement was observed in 20 (29%); in 7 (9%) – headache remained unchanged. The most common postoperative complication was neuro-ophthalmological disorders (23%), with a tendency for resolution in the long-term follow-up period. Neuro-ophthalmological symptoms at last follow-up included upward gaze palsy (6%) and skew deviation (5%), followed by convergence disorders (3%) and eyelid-retraction (2%). Natural course group: PC size remained stable in 34 (87%) patients during the follow-up period. The patient’s gender or age was not a significant predictor of cyst growth (P = 0.4, P = 0.56).

Conclusion:

The majority of patients with a newly diagnosed PC remain clinically and radiologically stable. Patients with nonhydrocephalic PCs and intractable headaches experience significant relief in headache symptoms, but are at risk of mild to moderate neuro-ophthalmological disorders. The natural course of PCs and factors promoting their growth still remains poorly defined.

Diagnosis and Treatment of Pineal Region Tumors in Adults: A EURACAN Overview

Simple Summary

Pineal region tumors are rare intracranial tumors. A deeper knowledge of these tumors’ molecular mechanisms has been gained in recent years, which has led to a new classification and new potential systemic treatments. Surgery remains the mainstay of treatment, while radiotherapy and systemic therapy depend on histological, molecular, and clinical characteristics. This paper highlights recent developments in the diagnosis and treatment of these tumors.

Abstract

Pineal region tumors are rare intracranial tumors, accounting for less than 1% of all adult intracranial tumor lesions. These lesions represent a histologically heterogeneous group of tumors. Among these tumors, pineal parenchymal tumors and germ cell tumors (GCT) represent the most frequent types of lesions. According to the new WHO 2021 classification, pineal parenchymal tumors include five distinct histotypes: pineocytoma (PC), pineal parenchymal tumors of intermediate differentiation (PPTID), papillary tumor of the pineal region (PTPR), pinealoblastoma (PB), and desmoplastic myxoid tumor of the pineal region, SMARCB1-mutant; GCTs include germinoma, embryonal carcinoma, yolk sac tumor, choriocarcinoma, teratoma, mixed GCTs. Neuroradiological assessment has a pivotal role in the diagnostic work-up, surgical planning, and follow-up of patients with pineal masses. Surgery can represent the mainstay of treatment, ranging from biopsy to gross total resection, yet pineal region tumors associated with obstructive hydrocephalus may be surgically managed via ventricular internal shunt or endoscopic third ventriculostomy. Radiotherapy remains an essential component of the multidisciplinary treatment approach for most pineal region tumors; however, treatment volumes depend on the histological subtypes, grading, extent of disease, and the combination with chemotherapy. For localized germinoma, the current standard of care is chemotherapy followed by reduced-dose whole ventricular irradiation plus a boost to the primary tumor. For pinealoblastoma patients, postoperative radiation has been associated with higher overall survival. For the other pineal tumors, the role of radiotherapy remains poorly studied and it is usually reserved for aggressive (grade 3) or recurrent tumors. The use of systemic treatments mainly depends on histology and prognostic factors such as residual disease and metastases. For pinealoblastoma patients, chemotherapy protocols are based on various alkylating or platinum-based agents, vincristine, etoposide, cyclophosphamide and are used in association with radiotherapy. About GCTs, their chemosensitivity is well known and is based on cisplatin or carboplatin and may include etoposide, cyclophosphamide, or ifosfamide prior to irradiation. Similar regimens containing platinum derivatives are also used for non-germinomatous GCTs with very encouraging results. However, due to a greater understanding of the biology of the disease’s various molecular subtypes, new agents based on targeted therapy are expected in the future. On behalf of the EURACAN domain 10 group, we reviewed the most important and recent developments in histopathological characteristics, neuro-radiological assessments, and treatments for pineal region tumors.

Pineal cysts without hydrocephalus: microsurgical resection via an infratentorial-supracerebellar approach-surgical strategies, complications, and their avoidance

Indications for surgery of pineal cysts without ventriculomegaly are still under debate. In view of the limited data for pineal cyst resection in the absence of hydrocephalus, and the potential risk of this approach, we have analyzed our patient cohort focusing on strategies to avoid complications according to our experience in a series of 73 pineal cyst patients. From 2003 to 2015, we reviewed our database retrospectively for all patients operated on a pineal cyst. Furthermore, we prospectively collected patients from 2016 to 2020. In summary, 73 patients with a pineal cyst were treated surgically between 2003 and 2020. All patients were operated on via a microscopic supracerebellar-infratentorial (SCIT) approach. The mean follow-up period was 26.6 months (range: 6-139 months). Seventy-three patients underwent surgery for a pineal cyst. An absence of enlarged ventricles was documented in 62 patients (51 female, 11 male, mean age 28.1 (range 4-59) years). Main presenting symptoms included headache, visual disturbances, dizziness/vertigo, nausea/emesis, and sleep disturbances. Complete cyst resection was achieved in 59/62 patients. Fifty-five of 62 (89%) patients improved after surgery with good or even excellent results according to the Chicago Chiari Outcome Scale, with complete or partial resolution of the leading symptoms. Pineal cysts resection might be an indication in certain patients for surgery even in the absence of ventriculomegaly. The high percentage of postoperative resolution of quality-of-life impairing symptoms in our series seems to justify surgery. Preoperatively, other causes of the leading symptoms have to be excluded.