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Atypical Presentation of Pituitary Adenoma
Sujit Murade, HL Trivedi*, Chinmaya Sahu
 

A 33 year old male from Nasik came with complaints of bleeding from nose, weight gain, gradual loss of vision with bilateral proptosis since 8 years. Patient was diagnosed case of pituitary adenoma with cushing syndrome in 1997 and was operated for same but repeated MRI showed postoperative sellar and supra sellar mass in 2001.

Introduction
Pituitary adenoma is commonest tumour <br />
involving pituitary gland. They occur in patients of all ages, although uncommon in childhood. The exact incidence of pituitary adenoma can not be stated, as in normal population hyperplastic foci can found in histopathology.

Thus the incidence of pituitary adenomas in general population has been various estimated to be about 2% (Muhr et al, 1981), 9% (Mccromick and Halmi, 1971), 23% (castelo, 1936), 27% (Burrous et al 1981).

Pituitary adenomas usually as small, encapsulated lesion, clearly separated from adjacent normal gland and are 10 mm or less in diameter, they are termed as micro adenoma.

Tumour more than 10 mm size termed as macro adenoma.

Spread : As diaphragma seller offer the least resistance. Most tumour expand superiorly.

Floor : may extend into sphenoid sinus, laterally to cavernous sinus or above it in to orbital surface of frontal lobe or medial aspect of temporal lobe. Posteriorly it may encroach upon the basilar artery, ventral surface of brainstem.

In case of suprasellar extension, tumour may encroach upon the intracranial portion of optic nerves, optic chiasma or even some tumour may compress third ventrical and can result into non communicating hydrocephalus.

Case Report
A 33 year old male from Nasik, came with complaints of painless and gradual loss of vision, bilateral proptosis since 8 years and history of bleeding from nose; weight gain was also present. Family history was not significant. Past history - he was known case of pituitary adenoma with cushing syndrome and was operated via transphenoidal route for radical resection of invasive pituitary adenoma. Histopathology shown monotonous population of small round cells with spherical dense nuclei and moderate amount of eosinophilic cytoplasm. But there was recurrence of tumour. In 2001 MRI showed large lobulated soft tissue mass in sella region. Inferiorly mass extends through sphenoid into nasopharynx, multiple focal areas of hyperintensity were seen within. Anteriorly mass was extended into lesser wings of sphenoid and posterior ethmoid.

Superiorly extension has been into suprasellar cistern and inferiorly third ventricle, optic nerves and optic chiasma were inseparable from mass and laterally cancasement of both internal carotid arteries were noted; posteriorly extension into clivus was noted. On local examination visual acuity in right eye was finger count one meter and left eye was finger count three meter with bilateral axial proptosis about, more than 28 mm on hertle’s exophthalmometer non pulsatile, non reducible. Rest of anterior segment was normal. Slit lamp examination was within normal limit.. Intraocular pressure in both eyes was 17.3 mm of Hg .On fundoscopy both eyes shown optic atrophy. Perimetry was not possible, due to poor visual acuity. Thyroid function test was normal.

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Fig. 3 :  

Classification

  1. Chromophobe :- adenomas are more common.
    Patient present with symptom of hypopituitarism, light microscopic study shown agranular cells.
  2. Acidophilic :- associated with acromegaly or in young patients with gigantism. Microscopic study shows cell containing cytoplasmic granules that stained brightly with acid fuctin.
  3. Basophilic :- They present as Cushing syndrome and on microscopic examination shows cells with cytoplasmic granules that had an affinity for aniline dye to Mallory trichrome stain.

Clinical manifestation
Depends upon cell types composing tumour, extent of destruction of surrounding normal pituitary gland and degree of compression of surrounding structures.

Endocrine manifestation
— Cushing's syndrome, Cushing disease, Nelson syndrome.
— Addison’s disease
— Dysthyroidism
— Galactorrhoea and galactorrhoea amenorrhoea (Forbes Albright syndrome)
— Impotence, infertility, decreased libido
— Acromegaly and gigantism
— Hypo gonadism, hypopituitarism

Visual manifestation
Visual sensory dysfunction:- Bitemporal hemianopic field defect is the most common visual abnormality observed in patients.

The defect may be central, peripheral or combination of both, with or without splitting of macula, absolute or relative defect can be identified by red stimuli.

Many patients present with bitemporal scotomatous field defect with normal visual acuity these field changes may also be associated with colour perception defect.

The initial defect occur in superior temporal quadrant then move in direction to infero temporal to infero nasal and finally to superior nasal quadrant.

These defect are mostly asymmetrical. One eye may become completely blind while in other eye field defect remains relatively unchanged.

In addition to this patient may complain of difficulty in depth perception. In some cases damage to intracranial portion of both optic nerve and chiasma shows arcuate defect and less commonly central or cecocentral defect. Apart from this tumour may grow between optic nerve pushing them laterally where they become compressed by supraclinoid portion of internal carotid arteries result in bilateral nasal field defect. Concomitant optic chiasma or optic nerve damage can result in incomplete incongurous homonymous hemianopi.

Damage to distal optic nerve on side near its junction with optic chiasma produce loss of visual acuity in ipsilateral eye associated with decrease in colour vision. This is known as Junctional or anterior clinoid syndrome.

Some patient may experience visual hallucinations related to cerebral peduncles compression.

Motor dysfunctions
Oculomotor nerve paresis usually associated with compression of lateral wall of cavernous sinus by tumour. It may be associated with trigeminal neuropathies. Moderate ipsilateral proptosis due to venous stasis and reduction of venous out flows from orbit.

Patient with ocular motor neuropathy may complaint of diplopia or visual confusion unless they are blind, or have amblyopia.

There may be see saw nystagmus probably related to damage to interstitial nucleus of Cajal.

Motor dysfunctions
— Headache – supraorbital or periorbital region associated with photophobia related to stretching of branches from trigeminal nerve by tumour.
— Deterioration of mental functions and personality changes
— Cerebrospinal fluid rhinorrhoea due to erosion of sphenoid sinus by adenoma.

Motor dysfunctions
— X-ray skull
- AP
- Lateral
— CT scan
— MRI
— Serum hormonal analysis depending on clinical presentation
— Immunocytological analysis
— Visual field

Treatment
Goals are

  1. To preserve and improve visual function
  2. Reversal of hypersecretion syndrome with preservation of normal pituitary function
  3. Control of growth of tumour

Surgical treatment
Excision of tumour via
— Transfrontal craniotomy
— Lateral subtemporal approach with orbital extraction
— Transphenoidal approach

Through intranasal route or endonasal route.

Medical therapy
To control hypersecretion of hormone and to maintain normal pituitary functions

Radiation therapy
Tumour secreting growth hormone respond well to radiation therapy.

Prognosis
Endocrine : In majority of cases after removal of tumour, there is regression of symptoms but remission rate is also high.

Visual : Depends on preoperative visual field defect, visual acuity of, duration, severity of visual loss and presence or absence of optic atrophy.

Discussion
Pituitary adenoma is most common tumour of pituitary gland. It generally manifests depending on type of cell involved and with its endocrine symptoms. Ocular symptoms are usually field changes due to compression of optic nerve and chiasma by tumour. Bilateral proptosis is very rare and is due to thyroid symptoms or by direct invasion of optic nerve by tumour cells.

References

  1. Alder FH, Austin G, Grant DC. Arch Ophthal 40 : 579-600.
  2. Bakay L. Pituitary adenoma necrosing 7 : 240-55..
  3. Chamlin M Bavidoff. Ophthal changes produced by Pituitary tumour. Amer Journal Ophthal 1971; 353-68.
  4. Wybar K. Visual field defect in chromosomal lesion tran. Amer Med Ass Sect Ophthal 1963; 112 : 16-39.
  5. Medras SP. Neurophthal St Louis. The CV Mosby Co 1968; 4 : 178-89.
  6. Fredric C Blodi. Eye symptoms in brain tumor 189-211.
  7. Nail R Miller. Clinical neuroophthalmology 3; 1433-73.
  8. Rovit RL. Eye signs in patient with cushing syndrome and pituitary tumour. Arch Ophthal 1968; 79 : 512-22.


*Ag. HOD, Department of Ophthalmology, BYL Nair Ch. Hospital, Mumbai 400 008.

*Resident, ++Chief Physician; +++Chief Surgeon and Director; KJ Hospital, Chennai - 600 084.
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