FRI324 Pituitary Macroadenoma With Carcinomatous Transformation And Multiple Cranial Masses And Spinal Leptomeningeal Carcinomatosis: A Case Report

Disclosure: C. Cristancho: None. G. Szabo: None. Background: Aggressive pituitary tumors are invasive tumors not responding to standard therapies and presenting with multiple local recurrences; if metastases occur, the tumors are defined as pituitary carcinoma (PC) Clinical Case: 51- year-old Hispanic woman with history of pituitary macroadenoma diagnosed at the age of 41, when presented with weight gain and decrease in visual acuity. Per records initial Brain MRI reported hyperintense sellar lesion of 2.1x2.3x2.6 cm with supra-sella extension and shift of optic chiasm. Patient had 4 pituitary surgeries between 2014-2018 due to growth and had radiation and Temozolomide between 2018-2020. Pathology was diffusely positive for ACTH, PRL, and Ki-67 was 10-20%, P 55 positive staining was 25-30%. As a result from pituitary surgeries patient developed central hypothyroidism, and central AI. Subsequent mornings cortisol were nl between 16-18. No UFC or LNSC were available. MEN1 negative. Brain MRIs done between 2019 and 2020 showed stable 13x8 mm residual pituitary mass with postoperative changes. Patient denied history of diabetes, fragility fractures, HTN, DVTs. She had regular menstrual periods until age of 42. Had left adrenal mass resection in 2019 with benign pathology results. During her initial endocrinology visit her ROS was positive for lower back pain and mild proximal muscle weakness. Patient denied visual changes, headaches, skin changes, polydipsia or polyuria. Physical exam was remarkable for small buffalo hump, and 5-/5 proximal muscle weakness. Negative for moon face, purple striae, acanthosis nigricans, hirsutism, acne. Initial tests were consistent with ACTH-dependent CS: elevated cortisol PM: 18.2 (n <10ug/dL) and LNSC 0.58 and 0.64 mcg/dl (n <0.09), 24-hr UFC 264 (n <50 mcg/dl), abnormal ACTH 150 (n <50 pg/ml).Brain MRI revealing extra-axial mass of 1.6 x1.1 cm overlying posterior aspect of right cerebellar hemisphere and focal lesion in left prepontine cistern of 0.8 cm. Leptomeningeal Enhancement. No sellar mass. Spine MRI showed scattered nodules lining the cord throughout the cervical and upper thoracic spine concerning for metastatic disease. Right cerebellar mass biopsy positive for metastatic pituitary neuroendocrine tumor corticotroph cell subtype, ACTH, chromogranin A, synaptophysin positive; PRL, TSH, GnRH, alpha subunit staining was negative; Ki-67 of 2%. Temozolomide, Capecitabin, and Ketoconazole 200 mg TID were started. Subsequent LNSC <0.03 and <0.03 mcg/dl, UFC at 3 different times were 12.8, 11.2 and 8.1 mcg/dl showing rapid decrease of cortisol levels in a 4-week period. A block-replace approach was decided with Dexamethasone 1 mg daily and a lower dose of Ketoconazole 200 mg BID. Patient reports no side effects. Presentation: Friday, June 16, 2023