Objectives. - Semantic-pragmatic disorder affects the use of language in a social context. However, therapists do not agree upon whether semantic-pragmatic disorder belongs to the autism spectrum or if it is an entirely separate condition. Rapin and Allen first defined semantic-pragmatic disorder (SPD) in 1983 as a language disorder. Confusion surrounds the use of diagnostic terminology in the area of SPD, where neurology, psychology, psychiatry and speech and language therapy converge. Nowadays, the most common definitions of SPD are: language impairment; manifestation of an autistic spectrum disorder; disorder between language impairments and autistic spectrum disorders; multiple complex developmental disorders. Recently DSM-5 has identified a new diagnosis called social communication disorder. This category is characterized by a persistent difficulty with verbal and nonverbal communication that cannot be explained by low cognitive ability. Symptoms. include difficulty in the acquisition and use of spoken and written language as well as problems with inappropriate responses in conversation. The disorder limits effective communication, social relationships, academic achievement, or occupational performance. This paper discusses the characteristics of semantic pragmatic disorder as well as social communication disorder and how to manage them. Its goal is to sensitize children psychiatrists and children psychologists about this problem, to arrive at a more precise diagnosis and to prescribe more accurate treatments. Patient. - In this article we present a single clinical case based on the story of a young boy called Mark. This case is interesting because at the age of six, Mark was diagnosed with an autistic spectrum disorder. Later on, at the age of eight a new examination pointed to language impairment. As an early teenager, at the age of 13, Mark was reevaluated and diagnosed with a multiple complex developmental disorder. Results. - Up until today the literature does not provide clinical studies that allow us to differentiate semantic-pragmatic language disorders, disorders of the autistic spectrum and multiple complex developmental disorders. However, after having interrogated speech therapist and clinicians, we have observed clinical individual differences throughout the course of the treatment. Compared to children suffering from an autistic spectrum syndrome, children that exhibit a semantic-pragmatic language disorder seem to have the following characteristics: initially a fascination for details that is less significant but that decreases with time until it finally might disappear; a continuity of ritual behaviors that is initially less significant but that decreases with time until it finally might disappear; a better eye contact in their relationship with others; a better variability of facial expressions; a better capacity to generalize from what they have learned from a new situation; a weaker requirement of invariance even if the interests might be restraint; no or few stereotypes that diminish strongly with time until they eventually disappear; persevering difficulties in the use of personal pronouns above the age of seven; late, but spontaneous acquisitions of symbolic play and in pretend play. These clinical elements can guide us in our reflections concerning the differential diagnosis. They deserve a deeper understanding about their validity during diagnosis. Conclusions. - The symptomatology of the semantic-pragmatic syndrome is complex and gives rise to several different diagnostic hypotheses. This points to the importance and necessity of a multidisciplinary evaluation. The complete and detailed medical history of the child's development, the persisting symptoms and the IQ profile are elements for which we have to remain attentive. This is important to guide us in our differential diagnosis and in our treatment. (C) 2015 Elsevier Masson SAS. All rights reserved.