Endocrine Abstracts

JOINT3447

Introduction: Pituitary incidentalomas are incidental findings in the pituitary gland, detected on imaging performed for unrelated reasons and are present in approximately 10–38.5% of imaging studies. Nevertheless, the majority are microincidentalomas (<1.0 cm), while macroincidentalomas (≥1.0 cm) have a prevalence of approximately 0.16% on magnetic resonance imaging (MRI) and 0.2% on computed tomography (CT). Current guidelines recommend screening for hypopituitarism in lesions ≥6.0 mm and MRI monitoring due to their potential for slow growth and symptomatic progression. However, the limited long-term follow-up studies of macroincidentalomas compromise a full understanding of their natural progression.

Objetives: We aim to study patients diagnosed with pituitary macroincidentalomas followed at our referral center, focusing on their clinical characteristics, therapeutic approach, and clinical outcomes.

Methods: We retrospectively reviewed all macroincidentalomas (pituitary adenomas ≥1.0 cm diagnosed in an imaging study requested for a reason not related with the adenoma) followed at our center (Instituto Estadual do Cérebro Paulo Niemeyer). Demographical, clinical, biochemical and radiological data at diagnosis were collected. The frequency of tumor growth, vision impairment, apoplexy and new anterior pituitary deficit was evaluated in the follow-up.

Results: A total of 57 patients were included [(56% females, median age at diagnosis 70 years-old (38 – 85)]. Median maximal tumor diameter and tumor volume at diagnosis were 2.1 cm (1.0 – 4.0 cm) and 2.97 cm³ (0.22 – 18.62), respectively. Any anterior pituitary deficiency was observed in 28% of the patients at diagnosis, the most frequent being hypogonadism, that was observed in 21% of the cases. Median follow-up was 4 years (1 – 9 years) and tumor growth was observed in 18% of the tumors while apoplexy occurred in 5% of the tumors. Tumor growth was observed after a median of 24 months (3-48). Vision impairment was observed in 21% of the patients during follow-up. Surgery was performed in 19 patients (33%) due to compression of the optic chiasm with or without vision loss or tumor growth. New pituitary deficiency was diagnosed in six (11%) patients. There was no difference in median age, maximal tumor diameter or tumor volume at diagnosis between tumors that grew and those that remained stable.

Conclusions: Macroincidentalomas are rarer than microincidentalomas but require close follow-up as approximately 18% will present clinically significant growth and one-third will require surgical treatment. Nevertheless, apoplexy is not frequent. Hypopituitarism is present in about 30% at diagnosis and should be evaluated in all patients upon diagnosis.