Pituitary tumours are mostly not cancerous, but they can cause vision loss and hormone imbalances that lead to other complications. Dr Thomas Tan Choo Heng, Head and Consultant, Neurosurgery, NNI@Sengkang General Hospital explains more about pituitary tumours, the different types and how they are treated.

The pituitary gland is a pea-sized hormonal gland that sits at the base of your brain, just behind the nose. Its main role is to produce and release hormones that control essential functions throughout the body, including reproduction and how the body uses energy (metabolism).

A pituitary tumour is an abnormal growth in the pituitary gland. An estimated 200 to 300 new cases of pituitary tumours are diagnosed in Singapore every year.

“Pituitary tumours are usually not cancerous so they do not spread to other parts of the body. However, they can cause hormone imbalances and vision problems depending on the size and location of the tumour,” says Dr Tan.

Types of Pituitary Tumours
There are two main types of pituitary tumours based on whether the tumours secrete excess hormones.

Non-Functioning Pituitary Tumours
These tumours do not secrete excess hormones and are the most common type of pituitary tumour. A small tumour does not cause any symptoms and goes undetected. However, it is possible for a tumour to grow, which may cause headaches and affect vision if the tumour compresses the optic nerves.
The optic nerves send messages between the eyes and the brain. The two optic nerves meet above the pituitary gland and a tumour can press on this nerve junction causing blurred vision and loss of peripheral vision (side vision) in both eyes. This can potentially result in blindness if left untreated.

Functioning Pituitary Tumours
These tumours secrete excess hormones which cause different symptoms or conditions depending on the type of hormone being released.

Prolactinoma tumours are the most common type of functioning pituitary tumour. They cause excess production of prolactin hormone which affects men and women in different ways.

Symptoms include:
  • Men: erectile dysfunction, enlarged breasts
  • Women: irregular menstruation, milky discharge from breasts
This condition is caused by pituitary tumours that cause excess production of growth hormone. This is the second most common type of functioning pituitary tumour. If it occurs in children and teenagers before they finish growing, it can result in giantism. 
In adults, symptoms include:
  • Large feet and hands
  • Change of facial features with enlarged nose, tongue and prominent jaw causing the person to look different from several years ago
  • Deep voice
  • Thick skin 
Patients with acromegaly are at higher risk of heart problems, colon cancer and carpal tunnel syndrome (numbness in hands).

Cushing’s disease
The pituitary gland produces a hormone called cortisol which regulates the body’s response to stress. Functioning pituitary tumours that secrete excess cortisol can cause Cushing’s disease which gets worse over time if not treated.

Symptoms include:
  • Weight gain
  • Osteoporosis
  • Muscle Wasting
  • High blood pressure
  • Reduced immunity
  • Abdominal stretch marks  
  • Bruising easily
Cushing’s disease can be treated by surgery to remove the tumour or controlled by medication if surgery is not possible. 

Pituitary Tumour Red Flags
  • Go to the nearest Emergency Department if you have sudden vision problems, especially loss of peripheral vision or blurred vision.
  • See your family doctor if you have unexplained tiredness or headaches that get worse and do not improve with painkillers
In rare cases, bleeding can occur inside pituitary tumours causing acute headaches, visual deterioration and lethargy due to a lack of cortisol hormone.

Rarer growths or tumours such as Rathke’s cysts, meningioma and craniopharyngiomas can sometimes be mistaken for pituitary tumours as they also occur around the pituitary region. MRI scans may determine the type of growth, however in some cases this can only be confirmed after it has been removed.

Treating pituitary tumours

Non-functioning Tumours
Patients with smaller non-functioning tumours which show no signs of growth or optic nerve compression do not require treatment – they are monitored with MRI scans of the pituitary gland. However, if a tumour is growing and presses on the optic nerve, it can be removed through minimally invasive surgery (see below).

Functioning Tumours
Patients with functioning tumours can be treated with minimally invasive surgery and/or medication depending on which hormone the tumour is producing.

Surgery to remove Pituitary Tumours
Due to the pituitary gland’s position at the base of the brain, minimally invasive surgery is used to remove the tumour. This operation requires a team approach: Ear, Nose and Throat (ENT) surgeons pass an endoscope – a thin tube with a lens and camera – up to the top of the nose where they create access to the pituitary gland. The neurosurgeon will then pass instruments up the nose to remove the pituitary tumour, guided by images from the camera.

Patients who undergo this operation usually spend four to seven days in hospital for monitoring due to the possibility of rare complications, such as bleeding, hormonal imbalances and leaking of cerebral spinal fluid which surrounds the brain. Once discharged, patients require follow-up with a multidisciplinary team of specialists from:
  • ENT

To ensure healing inside the nose

  • Endocrinology 

To assess the need for hormonal medication

  • Ophthalmology 

To monitor vision improvements and changes

  • Neurosurgery 

To check for tumour recurrence