Silent corticoptroph adenomas (SCA) are pituitary tumours positive on immunohistochemical staining for ACTH but without clinical evidence of hypercortisolism. They account for 1.16% of surgically removed pituitary adenomas. Most tumours are macroadenomas with suprasellar extension present in 87100% of the cases. They present with mass effects and this is in contrast to Cushings disease, which is mostly attributed to microadenomas. Reports suggest that these tumours may behave in a more aggressive way then other pituitary adenomas. In some cases hypercortisolaemia may be observed later in the course of the disease. There is a high rate of tumour recurrence and in one series it was reported to be about 33%. Recurrence has been reported to be more frequent in patients treated with adjuvant radiotherapy. Pathological indices (increased mitotic range and Ki-67) do not predict recurrence or malignant transformation of the tumours. Surgery remains the main therapeutic approach and repeated neurosurgical intervention may be required due to recurrence.
We describe the clinical course, imaging, and histology of four such cases who presented as large non-functioning pituitary macroadenomas with visual field defects, with no clinical or biochemical features of hypercortisolaemia.
This case series highlight the importance of early neurosurgical input, recognition of histology and regular surveillance for recurrence. Management and follow-up protocols should be planned taking into account their potential aggressive behaviour, particularly upon recurrence. The development of florid pituitary Cushings syndrome and local recurrence followed by metastatic disease (occasionally outside the central nervous system) has been reported.