Anterior panhypopituitarism in diffuse large B-cell stage IV lymphoma

Abstract

The most common presentation of metastases to the pituitary gland in systemic lymphoma is diabetes insipidus resulting from infiltration of the infundibulum/posterior lobe. We describe a 69-year-old man with diffuse large B-cell stage IV lymphoma who presented with anterior pituitary hypofunction, without features of posterior pituitary involvement. He presented with a few months of postural dizziness and hypotension, weight loss, fever, strabismus of right eye and a superficial abdominal wall mass. At this time he had no history of malignancy. Biochemically he had hypovolemic hyponatremia, secondary hypothyroidism and adrenal insufficiency. Further hormonal work-up revealed panhypopituitarism but no diabetes insipidus. Imaging of the brain, thorax and abdomen demonstrated diffuse intracranial pachymeningeal thickening and enhancement, multiple lymphadenopathies, a bulky right adrenal gland and a large left suprarenal mass, which were indicative of an infiltrative disease. Imaging of the pituitary showed heterogeneous enhancement of the anterior lobe with an unremarkable pituitary stalk and posterior lobe. Biopsy of the superficial abdominal wall mass revealed diffuse large B-cell lymphoma confirmed by bone marrow aspiration biopsy. Positron emission tomography (PET) scan confirmed diffuse systemic disease involving the right orbital apex, bilateral adrenal glands, bone and bone marrow, retroperitoneum and subcutaneous tissues; however, the pituitary gland, infundibulum and hypothalamus did not show any lesions on the PET scan. The patient was commenced on two cycles of chemotherapy but unfortunately died, thus recovery of pituitary function was not tested. Pure anterior pituitary hypofunction can uncommonly present in individuals with metastases to the pituitary gland, in contrast to the more common posterior pituitary/infundibulum involvement.