Pituitary Gland Tumors (Pituitary Adenomas)

Mr. (C.C.) presented to Al-Ahli Hospital with a complaint of progressive visual loss over six months. Upon evaluation at the Ophthalmology and Neurology Clinics, he was found to have Optic Atrophy and loss of parts of his visual field (Bitemporal Hemianopia). MRI revealed a large pituitary adenoma compressing on the optic apparatus (Fig 1). 

He was then referred to the Neurosurgery Clinic for further evaluation and treatment. Hormonal investigations revealed the presence of endocrinological disturbance due to over secretion of (Prolactin) Hormone from the tumor itself. This is one of the few tumors that can be treated with medicines alone. However, in this particular case, we opted for surgical tumor removal. That was based on the advanced stage of optic nerve injury, which could have left the patient blind had there been a further delay in removing the pressure from the optic nerves. The patient discussed the condition in detail and indications for surgery were explained. The surgical procedure was performed through the nostrils without requiring a craniotomy (skull opening). The surgery went smoothly, and the patient could recover vision promptly afterward. He was discharged on the 3^rd day after the surgery in excellent condition. Follow-up scan after surgery showed satisfactory results (Fig 2).

Pituitary Gland

The pituitary gland is a small oval-shaped pea-sized structure located in the base of the skull below the brain. It is connected to the brain, namely the hypothalamus, by a structure called the Pituitary Stalk. The hypothalamus is a vital part of the brain. It controls the balance of the body’s functions through hormones released from the pituitary gland. The latter is known as the ‘master gland’ because it controls the activities of most of the hormone-secreting glands in the body. 

Disorders of the pituitary gland  could include: 

1. 1. Endocrinological disturbance; due to increased or decreased Hormone secretion. Besides hormonal disturbance, patients may present with a wide range of symptoms that include Infertility, Erectile dysfunction. 
   2. Ophthalmologic disturbance due to pressure effect on the optic apparatus 
   3. Very large tumors could obstruct the CSF pathway and cause Hydrocephalus.

Anatomically, the pituitary gland is divided into three parts;

1. 1. The anterior part of the Pituitary gland is responsible for the secretion of the following hormones: Prolactin, Growth Hormone (GH), Adrenocorticotrophic Hormone (ACTH), Thyroid Stimulating Hormone (TSH), Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH). 
   2. The posterior Pituitary, on the other hand, is responsible for the secretion of Antidiuretic Hormone (ADH AKA Vasopressin) and Oxytocin. 
   3. The middle part of the gland is responsible for Melanocyte Stimulating Hormone (MSH) secretion.

Disturbance of the pituitary gland may be caused by a tumor of the gland (adenoma), infarction, infection (hypophysitis), or rarely metastatic tumors to the pituitary gland.

Incidence

Pituitary Gland tumors (Adenomas) account for up to 15% of intracranial tumors.

They are classified into Microadenmoa (Less than 10 mm in diameter) and Macroadenoma (More than 10 mm). 

Symptoms are usually caused by:

1. 1. Hormonal Secretions: Those tumors could produce hormones and are called secretary adenomas such as Prolactinomas (Tumors that secrete prolactin hormone …. etc.).  
   2. Compressive effect of adjoining structures mainly optic apparatus and possibly adjacent parts of the brain.

Presentation: Usually patients present to one of the following clinics according to their specific complaints; Ophthalmology, Endocrinology, Neurology, Gynecology, or Andrology.  Sometimes, these tumors are only discovered by chance upon performing brain images for other reasons. These lesions, which are incidentally discovered, are often named “Incidentaloma.”

Treatment: depends on clinical, endocrinological and radiological assessment. Those large tumors with compressive effects on nearby vital structures usually require surgical resection. An exception is Prolactinoma, which could often be treated with medications.  

When surgical intervention is indicated, the preferred standard approach nowadays is via the nostril (Trans nasal). Rarely do neurosurgeons nowadays remove these tumors by Craniotomy. The latter approach could still be utilized in certain exceptional circumstances. 

Radiotherapy is sometimes used as adjuvant therapy after surgery for pituitary adenoma. This applies to large tumors or those that cannot be removed completely to prevent tumor recurrence and regrowth.  

References

M E Molitch, Diagnosis and Treatment of Pituitary Adenomas: A Review. JAMA . 2017 Feb 7;317(5):516-524.

Samridhi Banskota and David C. Adamson, Pituitary Adenomas: From Diagnosis to Therapeutics. Biomedicines. 2021 May; 9(5): 494.

Warrick J. Inder and Christina Jang, Treatment of Prolactinoma. Medicina (Kaunas). 2022 Aug; 58(8): 1095.