Pituitary Tumor

What Is a Pituitary Tumor?

The pituitary gland is responsible for the production and secretion of various hormones.

It is connected to the diencephalon via the pituitary infundibulum and is divided into the anterior pituitary, the adenohypophysis, and the posterior pituitary, the neurohypophysis.

Here, the anterior lobe is an endocrine gland that produces and secretes hormones including TSH, which controls thyroid hormones, and ACTH to regulate the adrenal cortex. In addition, the growth hormone for growth processes and the FSH influences hormone production in the ovaries and testes. Also, prolactin controls the cycle and milk production in the mammary glands.

The posterior lobe anatomically makes up part of the diencephalon and stores hormones produced by the hypothalamus. These include ADH, which influences water balance in the body, and oxytocin, in turn, affects the labor process during birth and the bonding process between mother and child.

The pituitary gland is located in the bony sella turcica. It divides the middle cranial fossa. Optic nerve fibers also run there, which can be affected if a tumor occurs in this area.

Pituitary tumors are cell proliferation that mainly originates from the hormone-producing cells of the anterior pituitary lobe. They are then called adenomas, more commonly affect adults, and are usually benign, meaning they do not grow invasively or form tumor derivatives. However, because of the different ways hormones work, they can cause very other symptoms.

Is a Pituitary Tumor a Brain Tumor?

Pituitary tumors are located within the skull and involve the pituitary gland. Therefore, they are categorized as brain tumors and account for 10-15 percent of all intracranial neoplasms.

Which Pituitary Tumors Are There?

The majority of all pituitary tumors belong to hormone-active tumors. They can be classified into different groups depending on the type of hormone.

Prolactinomas account for about half of all pituitary tumors and can cause libido and potency disorders, cycle irregularities, and milk flow from the nipples due to the overproduction of prolactin.

Somatotropinomas cause a clinical picture called acromegaly. Due to increased growth factor production, patients suffer excessive growth of hands and feet and coarsening of facial features.

Corticotropinoma is associated with increased ACTH production and consequently increased secretion of the stress hormone cortisol from the adrenal cortex. This clinical picture is also known as Cushing's disease when it manifests and can cause mainly truncal weight gain, blood sugar dysregulation, high blood pressure, and acne.

Thyrotropinomas are very rare and manifested by hyperthyroidism due to increased stimulation of hormone release in the thyroid gland. Patients register this, for example, by excessive sweating, restlessness, and weight loss.

On the other hand, hormone-inactive tumors often show up late due to complaints caused by displacing growth. Pressure on surrounding structures results in visual field loss and headaches. Pressure on the pituitary gland can also lead to hypopituitarism, accompanied by hormone deficiency symptoms. This manifests, for example, with growth disturbances, menstrual disorders, hypothyroidism, or weakness of the adrenal cortex with decreased blood pressure and pallor.

Hormone-inactive tumors growing in the sella turcica can be, for example, craniopharyngiomas or meningiomas.

Malignant and aggressive tumors of the pituitary gland occur very rarely.

How Does a Pituitary Tumor Develop?

Tumors can develop due to changes in the genetic material, especially the inherited MEN1 syndrome, which is associated with clustered tumors of the glands, can be related to a pituitary tumor.

However, the exact background regarding the development of pituitary tumors is still unknown and the subject of current research.

Which Symptoms Do Tumors of the Pituitary Gland Cause?

In summary, tumors of the pituitary gland cause, above all, various disturbances of the hormone balance, which can become apparent in very different ways.

From a particular growth in size with pressure on neighboring structures in the brain, headaches, or, if the optic nerve is affected, double vision and visual field restrictions may also occur. Due to the tumor's location, the blinders phenomenon is especially typical with the limitation of the lateral visual fields.

How Is a Tumor of the Pituitary Gland Diagnosed?

Diagnosis is based on a detailed symptom-related questioning of the patient and imaging procedures of the head, such as MRI with contrast agent or, if necessary, a computed tomography examination, CT.

In addition, in the case of hormone-active tumors, a hormone analysis is helpful to classify the hormone production of the tumor more precisely. Furthermore, suppression tests and stimulation tests are also carried out, for example, in the case of somatotropinomas and corticotropinomas.

Pituitary Tumor Therapy

In the case of incidental findings, so-called incidentalomas, observational waiting may well represent a therapeutic strategy, provided the patient has no symptoms, and the tumor shows no increase in growth.

Surgical removal is the treatment of choice for most pituitary tumors if symptoms are noticed. This is carried out by a specialist in neurosurgery and is the treatment of choice for all pituitary tumors except prolactinoma. Drug treatment with dopamine agonists shows the best results because dopamine inhibits prolactin. This treatment leads to a rapid and effective reduction in prolactin secretion and shrinkage of the tumor, so surgery is usually unnecessary.

For tumors that cannot be completely removed or are found to be inoperable, radiation therapy may rarely be used.

In the case of hypofunction of the pituitary gland due to tumor or surgery, hormone replacement therapy must be administered.

How Is a Pituitary Tumor Operated?

Tumors smaller than 1cm, the microadenomas, are operated on through the nasal approach, which is done using unique mirrors and endoscopic instruments and can be used in 90-95 percent of all tumors.

The transcranial approach through the top of the skull is chosen for larger tumors.

Rehab After Pituitary Surgery

Following surgical removal of the tumor, close endocrinological follow-up care is provided by the hormone specialist and, if necessary, psychosocial follow-up care.

Life Expectancy and Prognosis

Pituitary tumors usually show a good prognosis, as they are generally benign and can be treated and controlled well by surgery or using a drug therapy regime.

With advances in therapeutic modalities and interdisciplinary care, almost all patients can be treated safely and effectively.

Sources:

• next.amboss.com/de/article/jK0_TS
• www.hirntumorhilfe.de/hirntumor/tumorarten/hypophyse/
• www.krebsgesellschaft.de/onko-internetportal/basis-informationen-krebs/krebsarten/hirntumor/hypophysentumoren.html
• www.patientenberatung.de/de/gesundheit/gesundheitsinformation/hypophysentumor
• www.aerzteblatt.de/archiv/50361/Therapie-von-Hypophysentumoren
• www.awmf.org/uploads/tx_szleitlinien/089-002l_S2k_Diagnostik-Therapie-hormonaktiver-Hypophsenaddenome_2020-04.pdf