Lymphoma metastasizing to the pituitary: an unusual presentation of a treatable disease

Lymphoma involving the pituitary gland is particularly rare. We present two cases of patients with pituitary lymphoma, both of whom were symptomatic from pituitary dysfunction. The first patient demonstrated pituitary involvement on imaging, with mild biochemical diabetes insipidus but clear hypoadrenalism. Both adrenals were grossly enlarged on CT scanning and biopsy of one of the adrenal masses confirmed the diagnosis of diffuse large B cell lymphoma. The second patient presented with clinical diabetes insipidus but with no obvious abnormalities on pituitary imaging. CT scanning of abdomen and pelvis, however, revealed widespread lymphadenopathy. Lymph node biopsy revealed a T cell-rich B cell lymphoma. Review of the English-language literature of all published cases of pituitary lymphoma in the presence of generalised disease in immunocompetent patients revealed 13 cases. Most patients had large B cell non-Hodgkin's lymphoma. Involvement of the anterior lobe of the pituitary was more frequently seen than in patients developing pituitary metastases from solid tumour primaries. Patients with advanced lymphoma including the pituitary also appear to have a better prognosis than patients presenting with pituitary metastases. This is an important diagnosis to make as rapidly as possible to allow the early institution of effective therapy.