Introduction: Marginal zone B-cell lymphoma is a rare disease which can be considerably difficult to recognize and diagnose when signs of systemic involvement are absent.
Case presentation: We report the case of a 57-year-old woman with initial olfactory disturbance, followed by psychosis, diabetes insipidus and hypothalamic eating disorder as an uncommon clinical presentation of marginal zone B-cell lymphoma.
Conclusion: Marginal zone B-cell lymphoma should be considered as a potential differential diagnosis in patients with hypothalamic disturbances.
Keywords: Bronchus-associated lymphoid tissue; Diabetes insipidus; Lymphoma; Mesencephalon; Olfactory disorder; Symptomatic psychosis.