Endocrine Abstracts

Introduction: Crooke’s cell adenomas are nonneoplastic corticotropes with cytoplasmic accumulation of cytokeratin filaments in response to glucocorticoid excess. They are rare subtype of corticotrope adenomas presenting less than 1 % of pituitary adenomas.

Case: 52 years old man attended Ophthalmology Clinic with 2 months history of right-sided reduced vision. He had a history of posterior polymorphous corneal dystrophy with a left corneal transplant and left cataract. As there was new bitemporal visual field loss, MRI was requested which showed a large pituitary macroadenoma (4x3x4 cm) with bilateral cavernous, sphenoid and ethmoid sinuses invasion with significant displacement of optic chiasm. Urgent endoscopic endonasal excision of the pituitary tumour was performed, however, due to size and location of the tumour, there was a limitation in safe resection and decompression of optic chiasm. Histology showed pituitary adenoma with focal expression of ACTH and high Ki67 index. Although the patient is obese with BMI of 45, there were no clinical signs of Cushing syndrome. After the operation, due to high ACTH 108 ng/l (reference range 0-46 ng/l), performed 24 hours urinary free cortisol and 1 mg dexamethasone suppression test which all came back normal. Repeated MRI three months after operation showed residual lesion involving sella, suprasellar cistern and left cavernous sinus with residual optic chiasm compression. He was referred to Neuro-Oncology team for consideration of radiotherapy due to ACTH expression and limited resection.47 GY radical radiotherapy was performed, unfortunately, MRI 3 months post radiotherapy showed an enlarged supra-sellar component to 17 mm from 12 mm with increased chiasmatic compression. Further endoscopic endonasal excision was performed and the patient become partial hypopituitarism requiring hydrocortisone and desmopressin replacement. The histology of pituitary adenoma is consistent with Crooke cell adenoma. Due to it aggressive nature, pituitary MDT suggested consideration for Temozolamide if further regrowth of the tumour. He then has two subsequent MRIs 6 months apart and remains stable appearances and is currently on regular MRI monitoring.

Conclusion: Crook’s cell adenomas are aggressive in comparison to typical corticotrope adenomas. Most Crook’s cell adenoma present as invasive macroadenomas with a high chance of recurrence therefore close surveillance is important for further management.