Prolactinoma is a prolactin-secreting pituitary adenoma and is the most common functioning pituitary tumour. Excess prolactin secretion causes reproductive and endocrine dysfunction by suppressing gonadotropin secretion. Prolactinomas are classified according to tumour size into microprolactinomas and macroprolactinomas. Unlike most pituitary tumours, the first-line treatment for prolactinoma is medical therapy rather than surgery.

Cushing's syndrome is a clinical condition resulting from prolonged exposure to excessive glucocorticoids from either endogenous or exogenous sources. The most common cause is the administration of exogenous glucocorticoids. Without treatment, Cushing's syndrome is often fatal because of cardiovascular disease, hypertension, or infectious complications.

Graves' hyperthyroidism is an autoimmune disorder in which thyroid-stimulating antibodies activate thyroid-stimulating hormone (TSH) receptors, causing excessive production of thyroid hormones. It is the most common cause of hyperthyroidism and may be associated with diffuse goitre and Graves' ophthalmopathy. Management aims to restore euthyroidism, relieve symptoms, and prevent recurrence and complications.

Toxic multinodular goitre (TMNG) and thyroid antibody-positive hyperthyroidism are causes of persistent thyrotoxicosis characterized by excessive production of thyroid hormones. Definitive treatment aims to eliminate the source of excess hormone production and achieve long-term euthyroidism.

Diabetic retinopathy (DR) is a chronic microvascular complication of diabetes mellitus and one of the leading causes of preventable blindness worldwide. Persistent hyperglycaemia damages the retinal blood vessels, resulting in retinal ischemia, increased vascular permeability, haemorrhage, exudation, and pathological neovascularization.