The concept of delusional disorder was coined only in 1977 despite being used in reports and observations over the last 150 years. In fact, it was Kraepelin's seminal work that defined the frame for delusional disorder. The presence of nonbizarre delusions in the absence of other mood or psychotic symptoms characterizes this disorder. These delusions can be persistent and have a stable course. Its prevalence is of 0,03% and the mean age of onset 40.

To describe the case of a central hospital psychiatric outpatient and it's comparison with the international available literature.

Retrospective analysis of the clinical process.

the authors present the case of a 78 years-old woman, married, previously healthy and functional, followed in an outpatient Psychiatric liaison consult since 2010. She presented with behavioural changes towards her husband and family developed after clinical discharge related with the treatment of Chronic Lymphocytic Leukemia 3 years before. She had a delusional belief that her husband had a romantic liason with the house keeper, not folding logic. She also had delusional interpretations of their behaviours. Despite that, she had no other psychopathology and functioned normally.

Our current understanding of delusional disorder is limited by scarce scientific data consisting mostly of individual case reports. The psychopathologic characteristics and age of onset make this case unique.