The pathology of pituitary, thyroid and adrenal gland tumours

Abstract

Endocrine tumours are relatively rare in clinical practice. Most are sporadic, but some occur in familial settings such as the multiple endocrine neoplasia syndromes type I (MEN I) and type II (MEN II, Figure 1). They are usually non-functional, but may secrete hormones that give rise to clinical syndromes. An example is Cushing's syndrome, caused by secretion of adrenocorticotrophic hormone (ACTH) from a pituitary adenoma or cortisol secretion from an adrenocortical tumour. Recent technical advances have enabled pathologists to provide specific diagnostic and prognostic information. For example, immunohistochemical staining with antibodies to specific hormones and other proteins can define the tumour as endocrine in nature and provide a hormone profile. The level of cell proliferation can be calculated by identifying cells positive for nuclear proteins that are expressed only when the cell is in cycle (e.g. Ki-67). This article should be read in conjunction with ‘Investigation and management of adrenal disease’, page 305.