P-074 PITUITARY MACROPROLACTINOMA WITH FLUID–FLUID LEVEL APPEARANCE: A RARE RADIOLOGICAL FINDING

Abstract Introduction Pituitary adenomas are the most common tumors of the sellar region, with prolactinomas representing the most frequent functional subtype. Their imaging characteristics are typically solid or cystic with variable contrast enhancement. A fluid–fluid level is an unusual radiological finding in pituitary adenomas and is more commonly associated with hemorrhagic or cystic lesions such as Rathke’s cleft cysts or craniopharyngiomas. Recognition of this rare feature is important to avoid misdiagnosis. Clinical Case A 25-year-old female initially presented to a gynecology clinic with menstrual irregularities and was prescribed oral contraceptives for cycle regulation. As the irregularities persisted, she was referred to the endocrinology clinic. On admission, her blood pressure was 121/76 mmHg, she had no galactorrhea, and other systemic examinations were unremarkable. Laboratory results revealed:Table 1: These results were consistent with macroprolactinoma. Visual field examination was normal. The patient was started on cabergoline 0.5 mg/week, after which serum prolactin decreased to 10.1 ng/mL at the first month, with resumption of spontaneous menstrual cycles by the second month. Follow-up MRI at 3 and 6 months demonstrated a stable lesion despite normalization of prolactin and clinical improvement. The patient was therefore referred for transsphenoidal surgery. Histopathological evaluation confirmed a densely granulated lactotroph adenoma. Conclusion Although prolactinomas usually present as solid or cystic lesions, rare cases may exhibit fluid–fluid level appearances on MRI due to intratumoral hemorrhage or cystic degeneration. Recognizing this pattern is crucial for differentiating it from other cystic sellar lesions. According to recent consensus, cystic macroprolactinomas can show variable cabergoline responsiveness, and surgical resection may be warranted when optic compression or incomplete biochemical remission persists.Figure 1Sagittal T2-weighted magnetic resonance image demonstrating a 21 × 18 mm sellar–suprasellar mass with a distinct fluid–fluid level appearance.