Teaching Case

A 63-year-old female presented to the neuro OPD with complaints of headache, tiredness, and malaise. There was no history of visual disturbance. Hormonal assay revealed decreased TSH and normal levels of growth hormone and prolactin.

The pituitary gland is enlarged asymmetrically in the right lateral aspect. Multilocular cystic lesion with septations noted within, off midline location (Figure 1a, yellow arrow). Posterior pituitary bright spot is seen in situ (Figure 1b, white arrow).

The contrast study shows lesser enhancement of the lesion (Figure 2). The pituitary stalk is displaced towards the left side (Figure 2, white arrow).

There is an encasement of the cavernous segment of the right ICA by the lesion (Figure 3).

No evidence of calcifications or suprasellar extension. No evidence of an intracystic nodule.

Background

Pituitary adenoma, the most common intrasellar pathology, is a benign neoplasm arising from the adenohypophysis, accounting for 10%–15% of all intracranial neoplasms [1]. Intratumoral haemorrhage and ischemic infarction are common with larger pituitary adenomas, resulting in haemorrhagic or cystic changes or both, leading to various signal intensities on MR imaging [2].

Clinical Perspective

Pituitary adenomas are classified into microadenomas (<1 cm), macroadenomas (>1 cm), and giant macroadenomas (>4 cm) [3,4].

About two-thirds of pituitary adenomas may secrete excess hormones. These functional adenoma presentations depend on the type of hormone it secretes. Prolactin followed by growth hormone is commonly secreted. Presentation of non-functional adenoma varies depending on the size and mass effect. Symptoms from the mass effect are mainly headache, visual impairment, and hormonal deficiency. Lateral cavernous sinus invasion can cause cranial nerve III, IV, or VI palsies. Compression of the pituitary gland or stalk (infundibulum) may cause hypopituitarism [5,6].

Imaging Perspective

MRI is the modality of choice for the evaluation of the pituitary and parasellar region. Typical imaging findings of an uncomplicated pituitary adenoma include slow enhancement compared with that of the pituitary gland, lateral deviation of the infundibulum, and isointense signal intensity relative to grey matter on T1-weighted imaging [7].

Cystic pituitary adenoma shows the presence of septations, a fluid-fluid level, and an off-midline location.

Rathke’s cleft cysts are usually central and cystic, with the presence of an intracystic nodule. Peripheral rim enhancement of normal pituitary seen [2].

Adamantinomatous craniopharyngiomas are also usually cystic, located above the sella, and lobulated. Calcifications can be seen, especially in the pediatric population. T1 hyperintensity is seen with high protein content [7].

Outcome

Patients with pituitary adenomas should be identified at an early stage so that effective treatment can be implemented. For prolactinomas, initial therapy is generally dopamine agonists. For all other pituitary adenomas, initial therapy is generally transsphenoidal surgery, with medical therapy being reserved for those not cured by surgery [4].

Take Home Message / Teaching Points

Pituitary adenoma has varied presentations, including cystic degeneration. Imaging findings of septations, fluid-fluid level, an off-midline location, and the absence of an intracystic nodule should help us differentiate it from the other differentials.

All patient data have been completely anonymised throughout the entire manuscript and related files.