Endocrine Abstracts

JOINT2154

Introduction: Familial Isolated Pituitary Adenomas (FIPA) are a rare hereditary condition, accounting for 1.9–3.8% of all Pituitary Neuroendocrine Tumors (PitNET) cases. The first identified gene underlying FIPA is AIP, which accounts for 10% to 20% of FIPA kindreds. FIPA occurs in the absence of other syndromic conditions (MEN1, Carney complex) and frequently presents at a younger age with larger and locally invasive GH-secreting adenomas that are less likely to respond to first-generation somatostatin analogues (SSA).

Results: In this study, we retrospectively analyzed 1,068 PitNET patients, who presented in our institute between 2019-2024, identifying a FIPA prevalence of 1.02%. We detected 11 families with FIPA, of which 3 were homogeneous and the remaining heterogeneous. The average number of affected members per family was 2.72 (± 0.96). The mean age at diagnosis was 47.2 years (± 15.72). Acromegaly was the most common PitNET type in the index cases, occurring in 10 out of 11 cases (90.9%), while one index case had a non-functioning pituitary adenoma (NFPA). Among the family members of the index cases, 7 were diagnosed with NFPA, 3 with acromegaly, and 1 with prolactinoma. Regarding the index cases, the mean diameter at diagnosis of the pituitary adenomas was 18.8 mm (± 8.79), with 8 out of 11 adenomas being invasive, as indicated by a Knosp grading. The mean number of required transsphenoidal surgeries was 1.27 (± 0.74). Among the index cases with GH-secreting pituitary adenomas, 6 out of 10 patients currently have active disease. Genetic screening for AIP mutations was performed in 6 out of 11 cases, yielding 4 negative results and 2 results pending.

Conclusion: In conclusion, the study highlights the low prevalence of FIPA, as well as the fact that none of the tested families had a positive result for AIP mutations. Ongoing research into novel genetic and epigenetic mechanisms of pituitary tumorigenesis, alongside the storage of DNA for future genetic testing, will enhance our understanding and management of this condition.