[Diabetes insipidus revealing primary malignant non-Hodgkin's lymphoma of bone]

Diabetes insipidus is a very rare, occasionally misleading, revealing symptom of non Hodgkin's malignant lymphoma. We report a case of this uncommon association and a review of the literature is done.

Soon after a transient attack of diplopia due to a 6th cranial nerve palsy, idiopathic cerebral diabetes insipidus was diagnosed in a 32-year-old immunocompetent man. As anterior hypopituitarism was absent, the patient was discharged and treated with desmopressin acetate. Six months later, recurrence of diploplia together with raised erythrocyte sedimentation rate was observed and B cell lymphoma was observed in the iliac bone and skull, with extension into the right cavernous sinus. Both tumoral lesions led to important uptake of gallium-67. After a 26-month follow-up following intensive chemotherapy including autologous peripheral stem cell transplantation and local radiotherapy, lymphoma symptoms had disappeared, but the patient's condition had only partially improved with regard to diabetes insipidus. The association of lymphoma and diabetes insipidus which has only been reported in 14 cases is discussed.

Since endocrine symptoms are often preceding hematological diagnosis, malignant lymphomas should systematically be viewed as potential etiology of diabetes insipidus. Magnetic resonance imaging which is more sensitive than computerized tomography in revealing brain lymphomas is mandatory. Gallium scan imaging might help guide the diagnosis in some instances.