Curricular fragmentation in Brazilian medical education significantly compromises the development of clinical reasoning, perpetuating the invisibilization of neglected diseases such as leprosy. The prioritization of economically profitable conditions, combined with the absence of an integrated approach, results in systematic diagnostic failures and inadequate management of endemic conditions. This study aimed to analyze patterns of diagnostic error among medical students when faced with a case of leprosy peripheral neuropathy, discussing how structural deficiencies in current medical training contribute to perpetuating the forgetting of leprosy in southern Brazil. Qualitative study grounded in reflexive thematic analysis and historical-dialectical materialism as the theoretical framework. A total of 405 medical students from 14 higher education institutions in the state of Santa Catarina participated and were presented with an interactive clinical case structured with 22 possible diagnostic pathways. Students’ clinical reasoning paths were mapped and categorized considering criteria of diagnostic accuracy, therapeutic adequacy, and potential clinical impact, allowing identification of recurrent error patterns and their practical implications. Seven distinct patterns of diagnostic error were identified, with late diagnosis and cognitive bias standing out as the most prevalent and clinically relevant. Marked diagnostic insecurity was observed, excessive and non-criteria-based use of complementary tests, and unnecessary referrals that compromised the resolvability of primary care. Notably, even students in advanced stages of training demonstrated substantial difficulties in early recognition and appropriate management of leprosy, indicating persistent gaps in medical education. The study revealed a profound structural failure in contemporary medical education, where the technicist model systematically reinforces the exclusion of neglected diseases from the effective curriculum and treats endemic disease topics superficially. Curricular reforms are imperative to strengthen diagnostic autonomy, minimize structural cognitive biases, and ensure medical training truly aligned with the epidemiological demands and priority needs of Brazilian public health, especially in areas of low leprosy endemicity.
Vitiritti et al. (Sun,) studied this question.