Atypical pituitary adenoma (silent corticotroph pituitary adenoma)

Abstract

Introduction: Pituitary adenomas are benign neoplasms with clinical behaviour and recurrence depending on the size of the tumour, therefore it is more common in nonfunctioning macroadenoma adenomas.Material and methods: Patient 1: A 40‐year female presented originally with visual field disturbance and underwent transphenoidal resection of pituitary macroadenoma in 1995. The tumour recurred in 1997 and 1998. Despite aggressive radiotherapy, the tumour metastasized to the vertebra in 1999. Patient 2: A 46‐year female presented with clinically nonfunctioning pituitary macroadenoma. She required two transphenoidal operations in 1998 and 1999, and underwent radiotherapy.Results: Patient 1: The initial biopsy shows silent corticotroph pituitary adenoma with occasional mitotic figures and Ki67 labelling index 2%. The recurrences in 1997 and 1998 showed increased nuclear pleomorphism, mitotic activity and Ki67 labelling (5% and 8%). The p53 was positive. The metastatic deposit in the vertebra showed similar histology but with Ki67 labelling of 15% and p53 immunoreactivity of 10%. Patient 2: The initial biopsy in 1998 showed silent corticotroph adenoma with Ki67 of 1%. The recurrence in 1999 showed increased mitotic figure, Ki67 labelling of 5% and p53 immunoreactivity.Conclusion: Silent corticotroph adenoma could be regarded as atypical pituitary adenoma with aggressive behaviour and high recurrence rate.