MON-095 Challenging Aggressive Corticotroph Adenoma: Metastasis or Extension of the Primary Lesion?

Abstract Disclosure: P.S. Mendes: None. N.N. Lima: None. A.E. Alexandre: None. M.V. Santos: None. H.R. Machado: None. S.R. Rauber Antonini: None. A.C. Moreira: None. A.C. Santos: None. M. De Castro: None. P.C. Elias: None. Background: Approximately 10% of pituitary tumors exhibit aggressive behavior (high growth rate, invasiveness, and resistance to conventional therapies), and about 0.2% progress to malignancy with craniospinal and systemic metastases. Clinical Case: A 15-year-old female presented with a 10-month history of weight gain with centripetal distribution, Cushingoid facies, spontaneous bruising, proximal muscle weakness, violaceous striae, irregular menstrual cycles, and depression. She also experienced cervical and thoracic vertebral fractures following a roller coaster ride. Biochemical tests confirmed ACTH-dependent hypercortisolism. MRI revealed an expansive sellar-suprasellar lesion (2.5 × 2.9 × 1.3 cm) with cavernous sinus invasion. She developed sudden-onset unilateral ptosis and ophthalmoplegia, suggesting cranial nerve compression. Transsphenoidal hypophysectomy was performed, leading to improvement in neurological symptoms but persistent hypercortisolism. Histopathology confirmed a corticotroph adenoma with extensive necrosis and a Ki-67 index of 5%. Follow-up MRI showed residual tumor (1.0 × 0.8 cm). Treatment with ketoconazole and cabergoline was initiated but discontinued due to toxicity and lack of remission. Radiotherapy (5040 cGy) was subsequently administered. Two years after radiotherapy, a dural-based lesion at the right orbital apex was identified, raising suspicion of metastasis. Biopsy confirmed an invasive Crooke's cell tumor (Ki-67: 20%). Concurrently, bilateral adrenalectomy was performed to address uncontrolled hypercortisolism. Following adrenalectomy, ACTH levels increased significantly (1485 pg/mL), and growth of an extra-axial lesion (1.6 × 1.1 cm) was observed, with no detectable tumor in the sellar region. The patient underwent nine cycles of temozolomide without clinical, biochemical, or radiological responses. Neuroaxis and abdominal imaging showed no other lesions. Further radiotherapy of the extra-axial lesion (3000 cGy) resulted in reduced ACTH levels and tumor volume. The patient is currently under clinical, laboratory, and radiological surveillance. Conclusion: This case highlights the challenges in managing aggressive Crooke's cell adenomas. Metastases were suspected due to invasion of adjacent structures, rapid lesion growth, and a high proliferation index. However, we proposed a unique pathway for lesion spread: originating from the primary sellar lesion, extending into Meckel's cave and subsequently into the orbit via dura mater disruption, and posteriorly involving the trigeminal nerve through the tentorial notch, without evidence of intracranial metastasis. Given the aggressive nature of Crooke's cell adenomas, close follow-up is essential. Developing alternative treatment options with novel molecular strategies to target these tumors and improve patient outcomes is crucial. Presentation: Monday, July 14, 2025