Frontal brain tumors often cause psychiatric disorders related to the functions of the prefrontal cortex. The prefrontal cortex expresses cognitive functions, which are superior functions concerning personality, conception, planning, ability to manage social relations. The dorsolateral part of the prefrontal cortex, if damaged, causes a depressive symptomatology, consisting of apathy, mood reduction and other symptoms. Kleist defined depression secondary to brain tumors, pseudodepression syndrome. It is a rare condition associated to brain frontal tumors, the depression that occurs first and not vice versa. The reasons are not clear. However, it is important to control depressed patients over the years, they must perform neuroimaging tests, avoiding the late discovery of a brain frontal tumor.