Diffuse Large B-Cell Lymphoma Presenting with Diabetes Insipidus: A Case Report

Objective: To present a rare case of pituitary gland involvement in paranasal and central nervous system (CNS) lymphoma. Methods: We describe the clinical presentation, laboratory data at presentation and follow-up, imaging studies, and management of the patient. A brief review of literature regarding pituitary involvement in lymphoma is also presented. Results: A 53-year-old woman with a history of human immunodeficiency virus (HIV) infection was evaluated for 6-month history of polydipsia, high-volume polyuria, and headache. Laboratory work-up was consistent with diabetes insipidus. Magnetic resonance imaging showed a 6-mm lesion in the posterior pituitary and ill-defined decreased T1 signal in the clivus and sphenoid sinus. She was treated medically with desmopressin for her urinary symptoms, with symptomatic improvement. In the interim, she was admitted for acute visual loss. Repeat imaging revealed a soft tissue mass involving paranasal sinuses with intracranial extension to the sella and hypothalamus. Biopsy confirmed the diagnosis of diffuse large B-cell lymphoma. The patient was treated urgently with multidrug chemotherapy and intraventricular methotrexate, resulting in neurologic improvement. After 12 cycles, the patient did well, with regression of the tumor and marked improvement of her urinary symptoms with decreasing desmopressin requirement. Conclusion: This is a rare case of hypothalamus-pituitary involvement in a diffuse, large B-cell lymphoma due to paranasal sinus involvement with CNS extension, presenting with central diabetes insipidus. Early detection with a high index of suspicion (particularly in patients with HIV) and treatment can lead to better outcomes. Abbreviations: AIDS acquired immune deficiency syndrome CNS central nervous system DI diabetes insipidus HAART highly active antiretroviral treatment HIV human immunodeficiency virus MRI magnetic resonance imaging