Frances Tustin’s pioneering work demonstrated the presence of autistic phenomena in non-autistic patients with severe difficulties, including anorexia, school refusal and psychosomatic symptoms. This paper describes stages in the psychoanalytic psychotherapy of a high-functioning four-year-old originally referred for aggressive behaviour, who developed psychosomatic mouth ulcers during his treatment. These originally seemed to serve as bodily containers for primitive anxieties (H. S. Klein) before becoming a step towards integration (Winnicott). The bodily countertransference played a central role in the therapy, and marked the change from a defensive function of the symptoms to a developmental function. The symptom itself improved markedly following work on the distinction between self and other. At the end of the therapy, the child described a game in which he developed frozen islands, in what seemed a telling representation of unintegrated aspects of his personality. The discussion includes the possible effect of transgenerational factors and of the patient’s very early experience.