Giant Pituitary Adenoma Presenting with Craniovertebral Junction Instability: A Case Report and Review of Literature.

A 47-year-old man presented with a large midline skull base lesion, with panclival erosion leading to a very rare event of CV junction instability causing severe neck pain and movement restriction as the predominant symptom presented. Sub-total excision of the lesion through the endonasal endoscopic transsphenoidal transclival approach followed by occiput-C2-C3 fixation was successfully performed as a one-stage procedure. Although the initial hormonal evaluation showed normal values, serial dilution confirmed very high prolactin levels. Careful evaluation for instability and the importance of the serial dilution method for prolactin levels is emphasized for proper treatment. We present an extremely rare scenario of invasive giant pituitary adenoma and review the pertinent literature.