Introduction:
Pineal cysts can develop at any age, but they are most common in people in their fourth decade. In a number of magnetic resonance imaging (MRI) investigations, the prevalence of pineal cysts ranged from 1.3 percent to 4.3 percent of patients investigated for various neurological causes and up to 10.8 percent of asymptomatic healthy volunteers. Magnetic resonance imaging is typically used to make the diagnosis of a benign pineal cyst and rule out malignancies in this region. In the future, transcranial sonography may be utilized primarily as a follow-up examination because a recent study showed that the results match those of MRI in terms of the detection of both pineal gland cysts and the pineal gland itself. Pineal cysts typically have no clinical effects and are asymptomatic for years.
Ataxia, motor and sensory impairment, mental and emotional disorders, epilepsy, circadian rhythm disturbances, hypothalamic dysfunction of premature puberty, and recently reported secondary parkinsonism are less common symptoms in patients. Asymptomatic cysts often have a diameter of less than 10 millimeters, whereas symptomatic cysts can range in size from 7 to 45 millimeters. However, in many situations, there is no correlation between the size of the cyst and the onset of symptoms. There is consensus that individuals who come with hydrocephalus, worsening neurologic symptoms, or enlarged cysts should have surgical intervention. Open surgery, stereotaxy, and neuro endoscopy can all be used to collect tissue samples from the pineal lesion.
What Is Pineal Gland?
The brain's tiny pineal gland, also known as the pineal body or epiphysis cerebri, is situated beneath the back portion of the corpus callosum. It releases the melatonin hormone and is a component of the endocrine system. By secreting melatonin, the pineal gland's primary function is to assist in regulating the circadian cycle of sleep and waking.
When it is dark outside, the pineal gland releases the most melatonin; when it is light outside, it produces less melatonin. Blood melatonin levels are at their lowest during the day and highest at night. As a result, melatonin is frequently referred to as a "sleep hormone." Despite not being necessary for sleep, melatonin helps people sleep better when their bodies are producing the most of it. Biologically female hormones and melatonin interact as well. It helps to regulate menstrual cycles, according to research. Neurodegeneration, which is the progressive loss of neuronal function, can also be defended against melatonin. Alzheimer's and Parkinson's diseases, for example, both exhibit neurodegeneration.
What Is Pineal Cyst?
Pineal cysts are frequently discovered inadvertently, are typically asymptomatic, and are widespread. Their significance stems mostly from the fact that they cannot be differentiated from cystic tumors, especially when large or unusual features are present. As a result, many individuals with these lesions receive extensive follow-up, probably with accompanying anxiety.
They often appear as a single, unilocular cyst inside the pineal gland. On T1-weighted imaging, the fluid signal attenuation may range from somewhat comparable to the cerebrospinal fluid to 60 percent being slightly hyperintense to the cerebrospinal fluid. In the majority of cases, a thin, smooth ring of contrast enhancement is visible, and calcifications are detected in 25 percent of cases.
What Is the Clinical Presentation Associated With Pineal Cyst?
Pineal cysts often have a diameter of less than 1 cm (centimeter) and show no symptoms. The superior colliculi can be compressed, and Parinaud syndrome can result when they are bigger and exhibit mass influence on the tectal plate. They may also cause obstructive hydrocephalus if the cerebral aqueduct is squeezed. Rarely, bleeding into a pineal cyst can cause it to rapidly expand and experience what is known as pineal apoplexy (unconsciousness). Most of the time, pineal cysts have been asymptomatic for years and have no clinical effects. If symptomatic most prevalent symptoms are:
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Headache.
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Vertigo (spinning sensation).
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Visual disturbance (impaired vision).
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Oculomotor abnormalities (abnormality associated with eye movement).
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Obstructive hydrocephalus (because of cerebral spinal fluid restriction, which results in increased pressure within the skull).
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Hypersomnolence (sleepiness).
What Is the Pathophysiology Associated With Pineal Cyst?
A pineal cyst consists of three overlapping layers:
1. Inner Layer: Glial tissue that is coarsely fibrillary and frequently contains hemosiderin.
2. Middle Layer: Pineal parenchyma calcification or non-calcification.
3. Outer Layer: Thin fibrous connective tissue in the outer layer.
Hormonal shifts may be involved in their creation since they are more frequently found in young women. The cyst initially grows and then diminishes as these women age. They often remain constant over time in males. The cyst often includes proteinaceous fluid, which on imaging, does not resemble cerebrospinal fluid. Additionally, internal hemorrhage might be present. The walls of pineal cysts lack a fully developed blood-brain barrier, just like the rest of the pineal gland.
The mechanism that starts their formation is unknown, but in magnetic resonance imaging studies' incidence rates indicate that pineal cysts typically originate in adolescence, increase during young adulthood, and then shrink in later life. Many pineal cysts only exhibit symptoms in the third or fourth decade, although it is unclear whether this is because the cysts were only beginning to form at the time of presentation or whether the symptoms are the result of an enlarged cyst from earlier in life.
What Are the Treatment Modalities Used to Treat Pineal Cysts?
1. Simple pineal cysts under 10 millimeters in diameter are considered a natural variant of the pineal gland and do not need to be followed up on.
2. In general, routine follow-up with contrast-enhanced MRI is not necessary for adults with incidental pineal cysts (regardless of size).
3. Children who develop incidental pineal cysts should be followed up every one to two years for interval follow-up MRIs because the cysts could expand and become symptomatic.
4. Patients with hydrocephalus brought on by pineal cysts should have combined endoscopic third ventriculostomy, endoscopic cyst drainage (fenestration), and cyst wall biopsy.
5. Long-term follow-up is unnecessary for atypical pineal cysts (multiloculated, augmenting, solid component), which are not primary pineal tumors (such as pineocytomas). A follow-up MRI in the first, third, and fifth year and detection of germ cell tumor markers may reassure patients and doctors.
Conclusion:
Since the development of magnetic resonance imaging, pineal cysts have been reported more frequently. Pineal cysts are incidental findings in up to four percent of magnetic resonance imaging tests, but symptomatic pineal cysts are extremely uncommon. Almost always, no treatment is required, and in most situations, if the cyst is tiny, no imaging follow-up is essential. Follow-up imaging may be required if cysts are larger than 10 to 12 millimeters in diameter because a cystic pineocytoma may resemble them. On imaging alone, it is impossible to differentiate between a cystic pineocytoma and a pineal cyst, although most cases can be resolved with careful imaging. Many would advise follow-up if a cyst was larger than 10 to 12 millimeters to ensure it was stable.
