Résumé : In this article, we propose to reconstruct a clinical case in the context of a medical institution taking care of hemato-oncology patients. This reconstruction is shaped by a psychoanalytical and differential approach based on a structural and subjective logic. More specifically, in the case of Mr V, we explore the self-other relationship in paranoia and its implications on the position of the clinician and the caregiving team in the transference process so that the subject may be best supported during the great physical and psychical suffering experienced at the end of life. We show how a differential approach is required from the very onset of the sessions to enable the clinician to be a bearable conversant, even during the radicalization of the paranoiac's approach to the other. We further indicate how a contingent configuration - the worsening of the patient's somatic state - and the appropriate medical response it elicits, constitutes triggers that promote the radicalization of the subject's paranoia. We emphasize both the ethical and operational implications of a differential approach to the subjective logics of oncological patients for whom violent bodily insults as well as death anxieties are daily occurrences. Our discussion highlights how the exploration of such clinical cases enables connecting their constituents with the psychoanalytical concepts developed by Freud and Lacan in the field of psychosis and paranoia and demonstrates both their richness and effectiveness in clinical practice. © 2012 Springer Verlag.