| Pinealoma | |
|---|---|
 | |
| Pineocytoma | |
| Specialty | Oncology |
| Treatment | Surgical resection, radiation therapy |
A pinealoma is a tumor of the pineal gland, a part of the brain that produces melatonin. If a pinealoma destroys the cells of the pineal gland in a child, it can cause precocious puberty.
The pineal gland produces the hormone melatonin which plays a role in regulating circadian rhythms. A pinealoma may disrupt production of this hormone, and insomnia may result.[ citation needed ]
Frequently, paralysis of upward gaze along with several ocular findings such as convergence retraction nystagmus and eyelid retraction also known as Collier's sign and Light Near Dissociation (pupil accommodates but doesn't react to light) are known collectively as Parinaud's syndrome [1] or Dorsal Mid-brain syndrome, are the only physical symptoms seen. This is caused by the compression of the vertical gaze center in the midbrain tectum at the level of the superior colliculus and cranial nerve III. Work-up usually includes Neuro-imaging as seen on the right.[ citation needed ]
A pinealoma may cause interruption of hypothalamic inhibiting pathways, sometimes leading to beta-hCG secretion and consequent Leydig's cell stimulation (endocrine syndrome).[ citation needed ]
Other symptoms may include hydrocephalus, gait disturbances, and precocious puberty.[ citation needed ]
Pinealomas can be due to proliferation of primary pineocytes (pineocytomas, pineoblastomas), astrocytes (astrocytoma), or germ cells (germinoma). [2] Germinomas are the most common tumor in the pineal gland.[ citation needed ]
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Some pinealomas are treated by radiotherapy, since surgical removal may be impossible due to the location. Radiotherapy can be successful in killing the tumour, and 50% of patients undergoing it survive to old age.
Of the different types of pinealomas, the type with the most favorable prognosis is the pineocytoma. [3]
The pineal gland is a small endocrine gland in the brain of most vertebrates. It produces melatonin, a serotonin-derived hormone, which modulates sleep patterns following the diurnal cycles. The shape of the gland resembles a pine cone, which gives it its name. The pineal gland is located in the epithalamus, near the center of the brain, between the two hemispheres, tucked in a groove where the two halves of the thalamus join. It is one of the neuroendocrine secretory circumventricular organs in which capillaries are mostly permeable to solutes in the blood.
Melatonin, an indoleamine, is a natural compound produced by various organisms, including bacteria and eukaryotes. Its discovery in 1958 by Aaron B. Lerner and colleagues stemmed from the isolation of a substance from the pineal gland of cows that could induce skin lightening in common frogs. This compound was later identified as a hormone secreted in the brain during the night, playing a crucial role in regulating the sleep-wake cycle, also known as the circadian rhythm, in vertebrates.
The anterior pituitary is a major organ of the endocrine system. The anterior pituitary is the glandular, anterior lobe that together with the makes up the pituitary gland (hypophysis) which, in humans, is located at the base of the brain, protruding off the bottom of the hypothalamus.
Pinealocytes are the main cells contained in the pineal gland, located behind the third ventricle and between the two hemispheres of the brain. The primary function of the pinealocytes is the secretion of the hormone melatonin, important in the regulation of circadian rhythms. In humans, the suprachiasmatic nucleus of the hypothalamus communicates the message of darkness to the pinealocytes, and as a result, controls the day and night cycle. It has been suggested that pinealocytes are derived from photoreceptor cells. Research has also shown the decline in the number of pinealocytes by way of apoptosis as the age of the organism increases. There are two different types of pinealocytes, type I and type II, which have been classified based on certain properties including shape, presence or absence of infolding of the nuclear envelope, and composition of the cytoplasm.
In medicine, precocious puberty is puberty occurring at an unusually early age. In most cases, the process is normal in every aspect except the unusually early age and simply represents a variation of normal development. There is early development of secondary sex characters and gametogenesis also starts earlier. Precocious puberty is of two types: true precocious puberty and pseudoprecocious puberty. In a minority of children with precocious puberty, the early development is triggered by a disease such as a tumor or injury of the brain.
Delayed puberty is when a person lacks or has incomplete development of specific sexual characteristics past the usual age of onset of puberty. The person may have no physical or hormonal signs that puberty has begun. In the United States, girls are considered to have delayed puberty if they lack breast development by age 13 or have not started menstruating by age 15. Boys are considered to have delayed puberty if they lack enlargement of the testicles by age 14. Delayed puberty affects about 2% of adolescents.
Hypopituitarism is the decreased (hypo) secretion of one or more of the eight hormones normally produced by the pituitary gland at the base of the brain. If there is decreased secretion of one specific pituitary hormone, the condition is known as selective hypopituitarism. If there is decreased secretion of most or all pituitary hormones, the term panhypopituitarism is used.
Pituitary adenomas are tumors that occur in the pituitary gland. Most pituitary tumors are benign, approximately 35% are invasive and just 0.1% to 0.2% are carcinomas. Pituitary adenomas represent from 10% to 25% of all intracranial neoplasms, with an estimated prevalence rate in the general population of approximately 17%.
Germ cell tumor (GCT) is a neoplasm derived from the primordial germ cells. Germ-cell tumors can be cancerous or benign. Germ cells normally occur inside the gonads. GCTs that originate outside the gonads may be birth defects resulting from errors during development of the embryo.
The endocrine system is a network of glands and organs located throughout the body. It is similar to the nervous system in that it plays a vital role in controlling and regulating many of the body's functions. Endocrine glands are ductless glands of the endocrine system that secrete their products, hormones, directly into the blood. The major glands of the endocrine system include the pineal gland, pituitary gland, pancreas, ovaries, testicles, thyroid gland, parathyroid gland, hypothalamus and adrenal glands. The hypothalamus and pituitary glands are neuroendocrine organs.
The epithalamus is a posterior (dorsal) segment of the diencephalon. The epithalamus includes the habenular nuclei, the stria medullaris, the anterior and posterior paraventricular nuclei, the posterior commissure, and the pineal gland.
A germinoma is a type of germ-cell tumor, which is not differentiated upon examination. It may be benign or malignant.
Ovarian diseases refer to diseases or disorders of the ovary.
Pineocytoma, is a rare, benign, slowly growing tumor of the pineal gland. The pineal gland is a small endocrine gland close to the center of the brain that secretes melatonin into the bloodstream. Pineocytomas can cause pressure and fluid build-up in the brain. They are more common in adults. Symptoms include vision problems, nausea, vomiting, memory problems, and headaches.
Pineoblastoma is a malignant tumor of the pineal gland. A pineoblastoma is a supratentorial midline primitive neuroectodermal tumor. Pineoblastoma can present at any age, but is most common in young children. They account for 0.001% of all primary CNS neoplasms.
Leydig cell tumour, also Leydig cell tumor, (testicular) interstitial cell tumour and (testicular) interstitial cell tumor, is a member of the sex cord-stromal tumour group of ovarian and testicular cancers. It arises from Leydig cells. While the tumour can occur at any age, it occurs most often in young adults.
Tuber cinereum hamartoma is a benign tumor in which a disorganized collection of neurons and glia accumulate at the tuber cinereum of the hypothalamus on the floor of the third ventricle. It is a congenital malformation, included on the spectrum of gray matter heterotopias. Formation occurs during embryogenesis, typically between days 33 and 41 of gestation. Size of the tumor varies from one to three centimeters in diameter, with the mean being closer to the low end of this range. It is estimated to occur at a frequency of one in one million individuals.
Van Wyk and Grumbach syndrome is a medical condition defined by a combination of hypothyroidism, precocious puberty, and ovarian cysts in pre- and post-pubertal girls or macroorchidism in boys.
An extracranial germ cell tumor (EGCT) occurs in the abnormal growth of germ cells in the gonads and the areas other than the brain via tissue, lymphatic system, or circulatory system. The tumor can be benign or malignant (cancerous) by its growth rate. According to the National Cancer Institute and St. Jude Children's Research Hospital, the chance of children who are under 15 years old having EGCTs is 3%, in comparison to adolescents, a possibility of 14% with aged 15 to 19 can have EGCTs. There is no obvious cut point in between children and adolescents. However, common cut points in researches are 11 years old and 15 years old.
Adrenalism describes the condition of an excessive or substandard secretion of hormones related to the adrenal glands, which are found directly superior to the kidneys. Adrenalism can be further distinguished as hyperadrenalism, referring to the excessive secretion of hormones, and hypoadrenalism, referring to the insufficient secretion of hormones.