BY SUNNDEEP CHOPRA:
Pituitary Tumours: These account for or then constitute between 10-15% of all intracranial (brain surface) tumours. A significant or then overwhelming majority of these are benign or non spreading adenomas that are classified or then sub-divided based upon their size, affected area or area of invasiveness, the patients endocrine status.
Metastases (secondary cancerous growth supplanted or then trans located form the location of the primary growth) may occur within the posterior pituitary of elderly or ageing patients. The differential or concrete diagnosis of a sellar region mass includes the administration of a craniopharyngioma, meningioma, and aneurysm (x-rays and radiological investigations).
Pituitary tumours or then para-sellar tumours may present or manifest itself as a space occupying or tenanting lesion within the pituitary fossa, gland or space or supra sellar and subsequently identified with the aid of either a CT scan or MRI as the case may be. Such a lesion may simply be a matter of chance or then incidental discovery during the course of a neuro-imaging exercise being carried out to identify some other anomaly or indication or may then come to light during the investigation of one of it’s many mass or side effects.
Sellar and para-sellar tumours are synonymous with a wide variety of side-effects depending upon their size and location. The most widespread but least specific of these is the proverbial headache which may be a consequence or direct result of the stretching or expansion of the diaphragm sellae.
Compression or depression of the neural or nerve related connections between the retina and occipital cortex (parts of the human eye) may lead to or cause a temporary/partial loss of vision or visual field defect.
Pituitary tumours are occasionally known to infarct or then bleed into systic lesions. This condition or predilection is chrtistened or termed ‘pituitary apoplexy’ and may result in the abrupt expansion or widening with local or then area specific compression symptoms and acute-onset hypopituitarism.
Non-haemorrhagic infarction or non bleeding infarction can also occur within/in a normal pituitary gland and predisposing or causatory factors or predilections include obststric haemorrhage or bleeding, diabetes mellitus and then raised or enhanced intracranial pressure.
Pituitary adenomas (tumours) are the most common and widespread cause of pituitary hormone hyper and hypo secretion (excessive and deficient secretion) syndromes in all adults and account for almost 15% of all intracranial neoplasms.
CLINICAL FEATURES OR SYMPTOMS:
Pituitary adenomas may present or announce themselves with either mass effect or then endocrinal disturbances or disruptions from status quo. Mass effect may cause or then result in btitemporal hemianopia due to the pressure exerted on the optic chiasma which in turn may result in the dysfunctioning of the cranial nerves. Endocrinal dysfunction is exclusively dependent on the secretory properties of the tumour if any.
Pituitary apoplexy (abrupt effusion or emission of blood) results in or gives birth to headaches, loss of vision, opthalmoplegia (eye related condition) and also possesses the inherent potential to alter or change the levels of consciousness and is primarily caused by the haemorrrhagic infarction of a pituitary tumour. The sudden/abrupt headache and meningism is similar or synonymous to the presentation or manifestation of aneurismal SAH.
Clinical syndromes for secretory pituitary tumours:
Prolactin: galactorrhoea, primary or secondary amenorrhoea and impotence.
Growth hormone: acromegaly and gigantism if prepubertal
Adrenocorticotrophic hormone: Cushing’s disease.
DIAGNOSIS OR INVESTIGATION:
Any patient with even the remotest suspicion of a suspected pituitary tumour should immediately undergo formal visual field and acuity testing, MRI scan of the pituitary region and baseline or cursory assessment of pituitary function including prolactin, fasting serum and urinary free cortisol, growth hormone and insulin like growth factor-I.
Establishing the patients endocrinal status particularly with regard to the ACTH-cortisol axis and prolactin is a pre-requisite. Cortisol deficiency or shortage should be immediately addressed or corrected particularly in the perioperative (period extending or varying from the time of admission for surgery to the time of discharge) period.
A high or excessive prolactin level may indicate or point towards a prolactinoma and preclude or then obviate the need for surgery; awareness of the fact that pituitary stalk (or end) compression or exertion of pressure from other tumours can moderately elevate the existing or then previously recorded prolactin levels.
The accurate diagnosis of an ACTH secreting tumour can prove to be an extremely difficult proposition and can/will often involve the usage or initiation of specialised testing like petrosal sinus sampling as well as the dexamethasone suppression test.
A conglomeration of disorders can present/manifest or announce themselves as a mass in the pituitary and hypothalamic regions, but the majority of intrasellar tumours are pituitary macroadenomas (most commonly non functional adenomas), most if not all suprasellar masses are craniopharyngiomas and para-sellar masses are most commonly meningiomas. Some lesions have distinctive neuroradiological features, but a precise or fool proof diagnosis involves surgical intervention or biopsy.
All patients with (para-) sellar space occupying lesions should mandatorily /voluntarily or periodically undergo pituitary function related assessments.
TREATMENT: An urgent or time bound initiation of requisite or prescribed treatment is a pre-requisite whenever there is the remotest evidence of undue pressure on the visual pathways. The probability of complete recovery of a visual field defect are directly proportional to the duration and longevity of the causative symptoms; full or complete recovery is only a remote possibility in cases of the defect being present for either four months or more.
Measuring or then analyzing the levels of serum prolactin is an imperative before the initiation of any surgical procedure whatsoever. The chances of completely sidelining or by passing any surgical intervention are extremely bright if the existing prolactin level is less than 5000mU/l as the lesion in question may be a dimunitive prolactinoma that may be treated with the therapeutic trial of a dopamine agent for a few pithy days.
A significant majority of operations on the pituitary gland are performed by taking recourse to the transsphenoidal approach (minimum invasive surgery) wherein the pituitary fossa is approached via an incision or cut made either under the upper lip or nose and routed through the sphenoid sinus.
Transfrontal ( a more complex form of surgery) via a craniotomy is almost exclusively reserved for cases of suprasellar tumours. Pituitary function should be necessarily tested within four-six weeks after the completion of the surgical procedure as a matter of routine as the same serves as an indispensable tool in the detection of any new hormone deficiencies or defects in the aftermath of the surgery.
Imaging through a slew of means is commonly repeated as a course of investigation within the matter of a few months and external radiotherapy may be taken recourse to reduce the underlying threat of recurrence or then introduced if the imaging shows indications of the presence of a residual mass and the histology of the same confirms or underlines the presence of a radiosensitive tumour.
Non functioning or benign tumours are followed up by repeated imaging at intervals depending or impinging on the size of the lesion and whether or not radiotherapy has been administered.
RADIATION: radiation is either used as a primary therapy for pituitary or parasellar masses or more commonly as an adjunct or auxiliary to surgery or medical therapy (treatment through the ingestion of prescribed drugs). Focussed or localized irradiation is achieved through precise and pinpointed MRI localisation using a high-voltage linear accelerator and accurate or precise isocentric rotational arcing.
An error free reproduction of the patient’s head position during multiple or repeated visits and steadfast maintenance of absolute and irresolute head immobility.
The role or significance of radiation therapy in the treatment of a pituitary factor is dependent on a multitude of factors including the nature and behavior of the tumour, and the ready availability of surgical and radiation related expertise.
Side-effects: radiation may be primarily responsible for the occurrence of transient nausea and weakness. Acute hair loss and prolonged absence of sense of taste are the long term side affects that have come to be associated with the usage of this method as a treatment of choice.
Medical therapy for pituitary tumours is highly topical and case specific. The initiation of this form of treatment is solely dependent on the type or classification of the tumour. Dopamine agonists are the treatment of choice in the case of prolactinomas. Somatostatin analogues and on occasion dopamines agonists are the chosen forms of treatment for acromegaly and TSH-secreting tumours. ACTH-secreting and non functioning tumours are generally oblivious to all treatments with drugs and require surgery and/or irradiation.
QUICK FACTS:
Pituitary Gland: Hypogonadism or growth related disorder
Hypothyroidism or anomalies in the functioning and secretion of hormones
generated within the thyroid gland.
Growth failure and adult hyposomatotropism
Hypoadrenalism.
Genetic Syndromes Associated with Pituitary Tumours: Several or numerous familial or family related syndromes have become almost synonymous with pituitary tumours and the gentic mechanisms for some of them have been unraveled or unearthed only in recent times:
Ø Multiple endocrine neoplasia: is an autosomal dominant syndrome characterized primarily by a genetic predisposition or then affinity to parathyroid, pancreatic islet and pituitary adenomas.
Ø Carney Syndrome: is synonymous with or then recognized by spotty skin pigmentation or colouration, myxomas and endocrinal tumours including testicular, adrenal and pituitary adenomas.
Ø Mc-Cune Albright Syndrome: consists of ployostsotic fibrous dysplasia, pigmented skin patches and a variety or multitude of endocrine related disorders including GH-secreting pituitary tumours, adrenal adenomas and autonomous ovarian function.
Ø Familial acromegaly is an extremely rare or then almost extinct disorder in which family members exhibit or manifest symptoms of either acromegaly or then gigantism.