Neurological Disorders

Symptomatic Metastasis to the Pituitary Gland: A Report of Three Cases and Review of the Literature

Abstract

Peter YM Woo, Ronald Li, Yung Chan, Timothy SK Chan, Peter KH Pang, Kwong-Yau Chan and John CK Kwok

Objective and importance: Symptomatic metastases to the pituitary gland are rare and often herald advanced systemic malignant disease. Distinguishing them from benign pituitary adenomas is challenging. The clinicoradiological features of three patients with pituitary metastases are presented. We also review the literature from 1970 to 2015 to formulate a diagnostic strategy. Clinical presentation: All patients were elderly with ages ranging from 65 to 82 years old. One had a previously undiagnosed prostatic carcinoma and two had known histories of primary gastric or parotid salivary gland carcinoma. Rapid visual deterioration was the most common symptom followed by ophthalmoplegia. Cranial diabetes insipidus (CDI) was observed after administrating hydrocortisone replacement in one patient. All patients had evidence of a solitary pituitary tumor on magnetic resonance imaging (MRI) of which two had discernible posterior pituitary signal changes. Trans-sphenoidal excision was performed for all patients with no procedure related complications. Two patients had visual improvement, but due to advanced systemic disease all succumbed within two months. A literature review of 475 pituitary metastases revealed that breast (37.1%) and bronchogenic carcinomas (22.1%) were the most frequently encountered primary malignancies. Among 290 symptomatic patients (22.1%) were the most frequently encountered primary malignancies. Among 290 symptomatic patients the commonest presentation was CDI (19.9%) and 12.1% had ophthalmoplegia. Of the 166 tumors with documented neuroimaging features, 31.3% had evidence of pituitary stalk thickening or enhancement followed by cavernous sinus invasion (30.1%) or was dumbbell shaped (27.7%). Conclusion: Diagnosing metastatic pituitary tumors is important for the treating clinician in order to avoid unnecessary surgical excision in patients with limited life expectancy. Patients older than 60 years, or with a history of cancer, presenting with CDI or ophthalmoplegia are red flag clinical features. For these patients we recommend investigations for occult primary malignancy when early posterior pituitary involvement orcavernous sinus invasion is demonstrated on MRI.