Endocrine Abstracts

JOINT2389

Introduction: ’Whispering’ pituitary adenomas (WPA) are a rare subtype of pituitary neuroendocrine tumors (PitNETs), characterized by immunohistochemical evidence of pituitary hormone production or specific transcription factors, along with biochemical activity, but minimal or no clinical symptoms. These adenomas represent 1.1–6% of surgically resected pituitary tumors and 17–22% of adrenocorticotropic hormone ACTH-positive tumors.

Aim: To describe three cases of pituitary adenomas later identified as WPAs. Case 1: A 36-year-old female with menstrual disturbances, headaches, and galactorrhea was diagnosed with a pituitary macroadenoma (1.4 × 1.2 × 1.15 cm). She was treated with cabergoline due to mild hyperprolactinemia, which improved her symptoms. Hormonal evaluations showed a morning cortisol of 21 μg/dl (10-20), ACTH of 37 pg/ml (7.2-63), and a normal overnight dexamethasone suppression test (ODST). After worsening headaches, she underwent transsphenoidal surgery. Histology revealed ACTH staining and a Ki-67 index of 3%. Two years post-surgery, the patient remains asymptomatic with no signs of Cushing’s disease. Case 2 A 76-year-old female was referred after pituitary macroadenoma apoplexy (adenoma size 1.9 × 1.6 cm), managed conservatively. The tumor had been discovered incidentally seven years earlier (1.3 × 1.1 × 0.8 cm), but no functional evaluations were conducted. The patient showed no clinical signs of hypercortisolism but had mild metabolic disturbances (overweight and osteopenia.). Biochemical tests indicated ACTH-dependent Cushing’s syndrome (ACTH = 91.7 pmol/l, ODST = 11.1 μg/dl, urine cortisol = 126.8 μg/gCR). Given tumor progression, surgery was performed, and histopathology confirmed an ACTH-positive pituitary adenoma with a Ki-67 index of <1%. Postoperative follow-up showed normalized biochemistry and no residual disease. Case 3: A 60-year-old male presented with a history of transsphenoidal pituitary adenomatectomy 17 years before. Postoperatively, he had developed deficiencies in the gonadotropic and thyrotropic pituitary axes and was placed on replacement therapy. Histological examination confirmed the diagnosis of a pituitary adenoma. Three years before, a follow-up pituitary MRI showed tumor relapse measuring 3.2 × 2.1 cm. The patient displayed no clinical signs of hypercortisolism, and hormonal evaluation revealed a morning cortisol level of 8.53 μg/dl, ACTH at 10.9 pg/ml. Surgery was repeated, histopathological findings were consistent with pituitary adenoma, with a Ki-67/MIB1 index of 2-3% and limited positivity for ACTH.

Conclusions: Corticotropic adenomas present with varied clinical manifestations, from subtle symptoms to no signs at all. Diagnosis relies on biochemical profiles and immunohistochemistry. Close monitoring post-surgery, including regular imaging and biochemical follow-up, is critical for managing these tumors effectively.