ABSTRACT
BACKGROUND: The human disorganization syndrome (HDS) is an extremely rare malformation syndrome that presents with a severe pattern of defects affecting different structures. METHODS: We describe a newborn girl presenting with HDS. Her clinical features included a large appendage arising from the right buttock as the only alteration, with size and shape of a lower member-like structure, and a pedicle of the extra limb structure. The surgical observations, the pathological results, evolution up to 6 months of age, and their potential causes are described, as well as a review of the literature. RESULTS: The MRI procedure also detected a multicystic mass located at the presacral region of the pelvis and perineum, without any dysraphism or other medullary anomalies. The X-ray showed that the member-like structure had an iliac wing, femur, tibia, fibula, and aberrant metatarsals. The review of the literature shows disparate defects of the published cases with HDS, which include some features pathogenically not related with this syndrome. CONCLUSION: We highlight the need to maintain restricted the clinical diagnosis for HDS to those concordant with a great disorganization of morphogenetic inductions affecting the three germ layers, which occur during the first four weeks of development. This is crucial to: (a) perform a correct diagnosis, which is essential to establish the prognosis and surgery procedures, (b) identify which is/are the cause/s, and (c) the adequate genetic counseling.