Giant, Recurrent Atypical Pituitary Adenoma Presenting with Atlanto-occipital Instability

Background Giant adenomas are >4 cm and represent 5 to 14% of all adenomas. The most typical presenting symptom is vision loss. The authors describe an unusual case of a giant, recurrent atypical adenoma presenting with severe mechanical neck pain and unilateral hypoglossal nerve palsy.

Case Report A 42-year-old man initially presented with vision obscurations and headache. He had imaging done that revealed a pituitary adenoma. As it was nonfunctional and correlated with his symptoms, he underwent transsphenoidal excision. His symptoms improved, but he then had symptomatic recurrence ∼20 months later that required a two-stage resection. Because of the invasive and aggressive nature of the tumor, the patient was counseled regarding adjuvant radiation treatment; the K_i-67 index was 7 to 8%. Unfortunately, he was lost to follow-up until 6 months later when he presented again with severe mechanical cervical spine pain, occipital headache, and hypoglossal nerve palsy with associated mild dysphasia. Imaging at this time showed significant tumor burden inferior to his optic apparatus. The clivus, jugular foramen, and down to the occipital condyles were involved with associated osseous erosion. The patient agreed to proceed with an occipital cervical fusion. His symptoms resolved within 24 hours of surgery, obese, with a history of invasive pituitary adenoma progression and symptoms of mechanical instability/pain from tumor progression into the occipital condyles. The patient has deferred further palliative surgery for his atypical adenoma; he is pending a Molecular Analysis for Therapy Choice (MATCH) study to assess for any possible chemotherapeutic options.

Discussion Prolactinomas are known to involve multiple compartments of the skull base. Indeed, these tumors have also been known to invade the craniovertebral junction. Targeted, dopamine agonists are highly effective in controlling these tumors; therefore, there are a few indications for surgery. Furthermore, when patients present with occipital headache and hypoglossal palsy, the symptoms are typically related to metastatic disease to the condyle; most of these patients are referred for radiation treatment. Although the published mainstay of treatment for these patients is nonoperative, the authors indicated surgical intervention for this particular patient because of the bilateral erosion of the occipital condyles and the severity of mechanical pain.

Conclusion Occipital condyle syndrome involves unilateral occipital headache along with ipsilateral hypoglossal palsy. The above patient had a variant of this syndrome due to the involvement of both condyles. Definitive management should be an occipital–cervical fusion to palliate symptoms, particularly when there is computed topography evidence of boney erosion at the bilateral atlanto-occipital joints.