A Pituitary Adenoma also known as Pituitary Tumour is depicted as a benign or noncancerous growth that primarily starts on the pituitary gland. Unlike other forms of malignancy, pituitary adenoma doesn’t metastasize and invade other healthy tissues of the body. But as the tumours on the pituitary gland thrive and grow bigger, they can create unnecessary pressure on the nearby tissues and organs and give rise to different characteristic indications.

The Pituitary gland is a small pea-sized gland that’s attached to the hypothalamus (the base of the brain), situated behind the nose at the base of the brain. It is structurally differentiated into two different lobes: the anterior (front) lobe and the posterior (back) lobe; with each lobe producing different hormones.
Pituitary adenoma

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These pituitary hormones include:

  • Adrenocorticotropic hormone (ACTH or corticotropin)
  • Growth hormone (GH)
  • Luteinizing hormone (LH)
  • Thyroid-stimulating hormone (TSH)
  • Antidiuretic hormone (ADH, or vasopressin)
  • Follicle-stimulating hormone (FSH)
  • Oxytocin
  • Prolactin

Pituitary tumours can be treated in different ways depending on the location and size of the tumour. The tumour can either be removed with surgery or its growth might be regulated with medications or radiation therapy or sometimes the hormones secreted from the affected part due to the tumour might be managed with medicine.

Types

Pituitary Tumours can be segregated into different types.

Depending on whether or not they make hormones:

Functioning Adenoma - These tumours usually synthesize hormones and they include Prolactinomas, Plurihormonal adenomas, Somatotroph adenomas, Gonadotroph adenomas, Corticotroph adenomas, and Thyrotroph adenomas).

Non-functioning Adenoma- These tumours do not synthesize any hormones.

Depending upon their size:

Macroadenoma: These are large-sized tumours that are bigger than 10 millimetres.

Microadenoma: These are small-sized tumours that are smaller than 10 millimetres or 1 centimetre.

Causes

Although the exact cause of pituitary adenomas is still not known, some pieces of research indicate that they might occur due to inherited genes that lead to mutations in the genes of the cells of the pituitary gland. These genetic changes in the pituitary gland cells trigger them to grow out of control both in size and number without dying on time and ultimately accumulating to form tumourous growths.

Risk Factors

Certain causative factors that aggravate the risk of pituitary adenomas include the presence of genetic conditions like:

  • Multiple endocrine neoplasia type 1
  • Multiple endocrine neoplasia type 4
  • X-LAG syndrome
  • Von Hippel–Lindau syndrome
  • Succinate dehydrogenase-related familial pituitary adenoma
  • Neurofibromatosis type 1
  • Carney complex

Symptoms

The characteristic physical manifestation of different types of pituitary tumours include:

Symptoms due to tumour pressure:

  • Headache
  • Seizures
  • Nausea and vomiting
  • Loss of side vision
  • Double vision
  • Pain in the facial muscles
  • Drooping eyelids

Symptoms due to low hormone production:

  • Tiredness or weakness
  • Excessive fatigue
  • Nausea and vomiting
  • Feeling a shiver or cold
  • Losing or gaining weight unexpectedly
  • Erectile dysfunction
  • Loss of interest in sex
  • Changes in menstrual cycles

Symptoms due to high hormone production:

Excess ACTH hormone production (Corticotroph Adenoma):

  • Weight gain and deposition of fatty tissue around the abdomen and upper back
  • Rounded face
  • Appearance of stretch marks on the abdomen and thighs
  • Easy bruising
  • Areas of darkened skin all over the body
  • Hormonal acne
  • Changes in menstrual cycles
  • Thinning of the arms and legs leads to muscle weakness
  • Thicker or more visible hair all over the body
  • Delayed healing of cuts, insect bites and infections
  • Erectile dysfunction
  • Loss of interest in sex

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Excess Growth Hormone production (Somatotrophic Adenoma):

  • Acromegaly causes large lips, nose and tongue; longer and broader lower jaw; and wide gaps between teeth
  • Excessive growth of hands and feet
  • Thicker skin
  • More sweating and intense body odour
  • Pain in the joints
  • A deeper voice

Excess Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH) production (Gonadotroph adenomas):

In women:

  • Change in menstrual cycles
  • Problems related to fertility and conception
  • Enlargement and pain in the ovaries
  • Ovarian hyperstimulation syndrome (OHSS)

In men:

  • Enlarged testicles
  • Higher levels of testosterone

Excess Prolactin Hormone production (Prolactinoma):

In women:

  • Irregular menstrual cycles
  • Lack of menstrual flow
  • Problems related to fertility
  • Loss of interest in sex
  • Milky discharge from the breasts without pregnancy
  • Breast tenderness

In men:

  • Erectile dysfunction
  • Growth of breast tissue
  • Problems with fertility
  • Loss of interest in sex
  • Less body and facial hair

Excess Thyroid Hormone production (Thyrotroph Adenoma):

  • Unintended weight loss
  • Rapid or irregular heartbeat
  • Excessive sweating
  • Tremor
  • Nervousness
  • Anxiety or irritability
  • Frequent bowel movements
  • Insomnia

Complications

If the condition is left untreated for a long time, it may lead to the following complications:

  • Problems with eyesight, including complete loss of vision
  • Heart problems
  • Problems with thinking and memory
  • High blood pressure
  • High blood sugar
  • Loss of bone mass and density
  • Seizure
  • Pituitary apoplexy
  • Permanent low hormone levels in the body

Diagnosis And Treatment

In case you notice any of the above-mentioned signs and symptoms, do consult a general physician at the earliest. The general may refer you to a specialist on confirmation of the benign tumour. The doctor usually does a thorough physical checkup, acknowledges the patient’s medical and genetic history and conducts the following diagnostics:

  • Blood and urine test
  • Complete eye examination
  • Imaging procedures like X-rays, PET scans, CT scans, and MRI scans

Treatment

The available treatment options for Pituitary Adenomas chiefly rely on the size, location and type of tumour and condition of the patient. These include:

  • Surgery (including Endoscopic transnasal transsphenoidal surgery and Transcranial surgery)
  • Radiation therapy (including Stereotactic radiosurgery, External beam radiation, Intensity-modulated radiation therapy and Proton beam therapy)
  • Chemotherapy
  • Treating pituitary adenomas with prescribed medications
  • Rehabilitation
  • Palliative care