Mayo Clinic, Jacksonville, FL Pituitary Carcinoma Presenting with Extensive Orbital Inflammation from Development of a Delayed Bone Metastasis Tasneem Kaleem MD1, Jennifer Peterson MD1, Vivek Gupta MD2, Whitney Woodmansee MD3, Rabih Tawk MD4, Murli Krishna MD5, Katherine Gold MD6, Victor Bernet MD3 Department of 1Radiation Oncology, 2Radiology, 3Endocrinology, 4Neurosurgery, 5Pathology, 6Opthalmology Mayo Clinic, Jacksonville, FL

Introduction Pituitary carcinoma is a rare condition defined solely by pathological evidence of a pituitary tumor at a distant site. Pituitary carcinoma comprises up to 0.2% of all pituitary tumors and commonly portends a poor prognosis. We present a case of a corticotroph pituitary adenoma presenting with orbital inflammation from development of a bone metastasis.

Initial Presentation A 75 year old female with history of hypothyroidism and Type II diabetes presented with diplopia and weight gain for several weeks. Physical exam: Right sixth nerve palsy and moon facies Pertinent hormonal studies : ACTH 116 pg/mL (10-60 pg/mL) Prolactin 23.9 ng/mL (<14 ng/mL) 24 hour urine free cortisol 172 mcg (3.5-45 mcg) Low dose dexamethasone test cortisol 15.4 mg/dL (<1.8 mg/dL) MRI revealed pituitary lesion measuring 19x16x18 mm displacing pituitary stalk and involving right cavernous sinus (Fig1). Findings were consistent with corticotroph adenoma with stalk effect

Clinical Course

Conclusion Presence of Biopsy proven metastasis confirms diagnosis of Pituitary carcinoma. Pituitary carcinomas most commonly present with metastatic spinal or meningeal lesions. Rarely, it can present in the bone with associated inflammation.

Take Home Points This case demonstrates the severity of the inflammatory process of metastasis. Inflammation can be misdiagnosed as infection and mask a metastatic lesion. Despite aggressive treatment of original tumor, delayed bone metastasis with edema can occur. Vigilant surveillance and follow up is required.