Pituitary glandPituitary glandpathologypathology

Clinical Clinical mmanifestations anifestations of of ppituitary ituitary ddiseaseisease

HyperpituitarismHyperpituitarism

HypopituitarismHypopituitarism

Local mass effectsLocal mass effects

Most cases of Most cases of hypofunctionhypofunction arise from destructive processes directly involving arise from destructive processes directly involving the anterior pituitary the anterior pituitary ((although other mechanisms although other mechanisms have been identifiedhave been identified))..

-e-empty sella syndromempty sella syndrome

Infarct of the pituitaryInfarct of the pituitary

CONGENITAL CONGENITAL AND AND DEVELOPMENTAL DEVELOPMENTAL DISORDERSDISORDERS

Many Many transcription factorstranscription factors are implicated are implicated in pituitary organogenesis, in pituitary organogenesis, and abnormalities of these factors may result and abnormalities of these factors may result in congenital hypopituitarism.in congenital hypopituitarism.

Idiopathic GH deficiencyIdiopathic GH deficiency

CYSTIC LESIONSCYSTIC LESIONS

Rathke’s cleft cystsRathke’s cleft cysts

Arachnoid cystsArachnoid cysts

Dermoid and epidermoid cystsDermoid and epidermoid cysts

INFLAMMATORY DISORDERSINFLAMMATORY DISORDERS

Lymphocytic hypophysitisLymphocytic hypophysitis

Granulomatous hypophysitisGranulomatous hypophysitis

Xanthomatous hypophysitisXanthomatous hypophysitis

Secondary hypophysitisSecondary hypophysitis

may be due to infectious agents may be due to infectious agents or may occur as part of a systemic process or may occur as part of a systemic process such as sarcoidosis, such as sarcoidosis, vasculitis vasculitis (Takayasu’s Disease,Wegener’s granulomatosis), (Takayasu’s Disease,Wegener’s granulomatosis), Crohn’s disease, Crohn’s disease, or Whipple’s disease. or Whipple’s disease.

It has been associated with ruptured It has been associated with ruptured Rathke’s cleft cyst, Rathke’s cleft cyst, necrotizing adenoma, necrotizing adenoma, and meningitis.and meningitis.

Infections associated Infections associated with AIDSwith AIDS

may also involve the pituitary.may also involve the pituitary.

PITUITARY HYPERPLASIAPITUITARY HYPERPLASIA

  may mimic adenoma.may mimic adenoma.

Somatotroph hyperplasiaSomatotroph hyperplasia

..  MammosomatotrophMammosomatotroph hyperplasiahyperplasia

Lactotroph hyperplasiaLactotroph hyperplasia

  Corticotroph hyperplasiaCorticotroph hyperplasia

Thyrotroph hyperplasiaThyrotroph hyperplasia

  

Gonadotroph hyperplasiaGonadotroph hyperplasia

Although Although hyperplasiashyperplasias may have similar may have similar clinical presentations, a reticulin stain clinical presentations, a reticulin stain can reliably distinguish adenohypophysial can reliably distinguish adenohypophysial hyperplasia from adenoma. hyperplasia from adenoma.

PRIMARY TUMOURS OF PRIMARY TUMOURS OF ADENOHYPOPHYSEAL CELLSADENOHYPOPHYSEAL CELLS

The classification of pituitary adenomasThe classification of pituitary adenomas

requires correlation between clinical manifestationsrequires correlation between clinical manifestationsof hormone hypersecretion, of hormone hypersecretion, radiological determination of size and invasiveness, radiological determination of size and invasiveness, and tumour morphology. and tumour morphology.   Tumour classification has been advanced Tumour classification has been advanced by the recognition of three main pathways by the recognition of three main pathways of adenohypophysial cytodifferentiation of adenohypophysial cytodifferentiation based on expression of transcription factors based on expression of transcription factors that regulate hormone genes.that regulate hormone genes.

The corticotroph pathwayThe corticotroph pathway

Somatotrophs, lactotrophs, Somatotrophs, lactotrophs, mammosomatotrophs, mammosomatotrophs, and thyrotrophsand thyrotrophs

ClassificationClassification

ADENOMAS ADENOMAS ASSOCIATED WITH ASSOCIATED WITH GROWTH HORMONE EXCESS GROWTH HORMONE EXCESS

Adenomas that produce GH excessAdenomas that produce GH excess with acromegaly or gigantismwith acromegaly or gigantism

represent up to 15% of pituitary adenomas. represent up to 15% of pituitary adenomas.

ADENOMAS ADENOMAS ASSOCIATED WITH ASSOCIATED WITH PROLACTIN EXCESS PROLACTIN EXCESS

THYROTROPH ADENOMAS THYROTROPH ADENOMAS ASSOCIATE WITH ASSOCIATE WITH TSH EXCESS TSH EXCESS

CORTICOTROPH ADENOMASCORTICOTROPH ADENOMASASSOCIATED WITH ASSOCIATED WITH ACTH EXCESS ACTH EXCESS

GONADOTROPH ADENOMAS GONADOTROPH ADENOMAS

CLINICALLY CLINICALLY NON-FUNCTIONING NON-FUNCTIONING PITUITARY ADENOMASPITUITARY ADENOMAS

PLURIHORMONAL PLURIHORMONAL PITUITARY ADENOMASPITUITARY ADENOMAS

PITUITARY CARCINOMA PITUITARY CARCINOMA

OTHER OTHER SSUPRASELLAR UPRASELLAR TUMORSTUMORS

Neoplasms in this location may induce Neoplasms in this location may induce hypofunction or hyperfunction of hypofunction or hyperfunction of the anterior pituitary, diabetes insipidus, the anterior pituitary, diabetes insipidus, or combinations of these manifestations. or combinations of these manifestations.

CraniopharyngiomaCraniopharyngioma

This benign, locally invasive tumour arises from remnants This benign, locally invasive tumour arises from remnants

Neuronal tumours, known as Neuronal tumours, known as gangliocytomasgangliocytomas are composed of mature neurones that resemble are composed of mature neurones that resemble hypothalamic ganglion cells. hypothalamic ganglion cells.

Gliomas of the sellar regionGliomas of the sellar region

MeningiomasMeningiomas

Granular cell tumoursGranular cell tumours

ChordomasChordomas

SchwannomasSchwannomas

UNUSUAL UNUSUAL PRIMARY TUMOURS PRIMARY TUMOURS

Germ cell tumoursGerm cell tumours

Hematologic neoplasmsHematologic neoplasms

Mesenchymal tumoursMesenchymal tumours

METASTATIC METASTATIC MALIGNANCIESMALIGNANCIES