Endocrine Abstracts

Introduction: The silent corticotropinomas (SC) account for 1.1–6% of surgically removed pituitary adenomas and 17–22% of ACTH-immunoreactive tumours. They do not cause prominent clinical features of hypercortisolism, nor biochemically evident, but show positive immunostaining for ACTH similar to functional corticotropinomas, They usually present as non-functioning adenomas (NFPA) with local mass effects and/or visual impairment.

Aim: To describe the clinical course of a patient operated for NFPA which later in time developed into active Cushing’s disease (CD).

Case presentation: The disease presented at the age of 18 years with oligomenorrhea, normal hormonal tests results for TSH, cortisol, LH, FSH, prolactin, and microadenoma 0.8 cm in diameter at MRI. Within a year patient underwent transnasal adenomectomy owing to the rapid suprasellar extension of the lesion at dynamic visualisation. For technical reasons, histological and immunohistochemical analysis was not performed.

At the next follow-up patient complained of persisted oligomenorrhea, the levels of TSH, cortisol, LH, FSH, prolactin remained in normal ranges, there was no data of recurrence on MRI.

At the age 21 years patient presented with clinical signs of CD. Lab data revealed high levels of ACTH/cortisol, absence of significant cortisol suppression at the 1 mg and 8 mg dexamethasone tests. The MRI-scan detected the macroadenoma 1.6×1.2×1.0 cm. The inferior petrosal sinus sampling distinguished pituitary CD. At the age of 21 the patient underwent the second transnasal adenomectomy however adrenal insufficiency did not develop. The immunohistochemical analysis showed ACTH-, LH-, FSH-, PRL-, CgA immunopositivity, negative expression for STH and TSH, ki-67 2%. Because of ineffectiveness of surgical treatment patient was directed to radiation therapy.

Conclusions: This case demonstrates the recurrence and transformation of NFPA into manifested CD during a period of 2 years. The knowledge of the immunostaining characteristics of NFPAs-are important for proper postoperative management.