Pituicytomas are rare tumours, originating from modified glial cells called pituicytes. The lineage of these tumours remains a topic of debate. Approximately 65 cases have been reported in the literature to date, since being formally recognised in 2007. We report a case where the final diagnosis was made after second surgery for late recurrence.
Case: A 54-year-old man presented with left sided visual disturbances in 1998 and underwent transcranial resection of a sellar/suprasellar lesion. Histology was atypical but was concluded as suprasellar meningioma following a second opinion. Surveillance MRI scan, 15 years later, revealed the previously stable small residuum to have grown into a sellar/suprasellar lesion. Tumour was removed endoscopically. The histology was compared with the 1998 sample and both were confirmed as pituicytoma, using newer immunohistochemistry methods.
Discussion: Pituicytoma was recognised as a distinct entity in 2000 and subsequently added to WHO-2007 classification of Tumours of Cranial Nervous System. Generally, these are slow-growing tumours. The presenting symptoms are due to mass effects, especially compression of optic chiasm. Clinical and imaging features are indistinguishable from other sellar tumours. This benign tumour is made up of elongated bipolar spindle cells in a rich capillary network. Immunostaining is often strongly positive for S-100, vimentin, and thyroid transcription factor 1 (TTF1), but negative for pituitary hormones and neuroendocrine markers like synaptophysin and chromogranin. TTF1 is helpful in distinguishing pituicytoma (TTF1 positive, as in this case) from meningioma, schwannoma, and pilocytic astrocytoma, which are TTF1 negative. Definitive management is total resection, often hampered by the hypervascularity. Recurrence within a few years after subtotal resection is well-documented. However, our case recurred 15 years after near-total resection. It is important to be aware that this highly vascular tumour has the potential to re-grow even after a decade. Long-term clinical, neuro-ophthalmic and MRI surveillance is essential.