An “unclassified diabetes” after a long duration of disease in a young subject: a case report

Unclassified diabetes describes diabetes that does not fit into other categories. This category is used temporarily when there is no clear diagnostic category, especially close to the time of diagnosis. This implies that paraclinical investigations or the natural evolution of the disease will allow a definitive classification. We present the case of diabetes initially classified as type 1 in an adolescent. For ten years, the patient had high insulin requirements with negative autoantibodies, significant residual insulin secretion, and for the last 3 months of life, remission of diabetes in the context of a wound of the thigh, before a sudden death from hepatocellular failure, pushing to reconsider the initial diagnosis. This clinical case highlights difficulties in obtaining precision in the etiological diagnosis of diabetes in some patients based either on clinical manifestation, biological assessment, or evolution. It also shows that unclassified diabetes subtypes may not be transient.