The orbitofrontal syndrome (OBS) is a neuropsychiatric syndrome secondary to damage in orbital areas of the prefrontal cortex. It is composed of cognitive, behavioral and affective symptoms of different grades of severity, often leading to permanent changes in personality. The case of a man who developed reactive, ego-dystonic, non-reflective and explosive aggression as part of an OBS secondary to a ruptured aneurism is examined. The clinical material is taken from multiple hospitalizations in a psychiatric clinic in Colombia, and from supportive therapy. A series of preliminary correlations are made between neuropsychiatric symptoms, neuropsychological data, neuroanatomical lesions as shown on neuroimaging and first-person subjective data. Using an affective neuroscience framework, it is hypothesized that damage to executive control of the RAGE system leads to altered functioning of neural hierarchies involved in affective processing, with affective attacks being experienced by the patient at a metapsychological level as ego-dystonic, presumably due to a fracture in inner ego boundaries. This would allow the emergence of raw affects, experienced as anomalous aggressive instincts unable to be re-represented, behaving as a repetition compulsion-like phenomenon at the expense of an absence of repression. As this is a single case analysis, any data emerging from this study should be contrasted with future evidence in these kind of patients. Cases like these should, however, lead to a more precise, neuroscience-informed, psychoanalytic theory of instincts.