Acalvaria: the first case report from Nepal.

INTRODUCTION AND IMPORTANCE: Acalvaria is a rare congenital malformation in which the flat bones of the cranial vault, dura mater, and associated muscles are absent while the central nervous system usually remains unaffected. It is an extremely rare congenital anomaly with only a handful of cases being reported in literature.

CASE PRESENTATION: The authors report a case of a 2-month-old male infant with acalvaria who was delivered at home and brought to our centre with the complaint of an abnormally soft skull. He was evaluated in a primary centre in rural Nepal. Parietal bones were missing bilaterally but no other abnormalities were found during the physical examination and investigations. Major differential diagnoses like anencephaly, cephalocele, osteogenesis imperfecta type II, and hypophosphatasia were ruled out with the help of history, physical examination, and available investigations and the case was diagnosed as acalvaria.

CLINICAL DISCUSSION: Acalvaria is a post-neurulation defect which is associated with anomalies of various organ systems. Radiological diagnosis, with supportive laboratory investigations, is the most reliable method of antenatal diagnosis.

CONCLUSION: Acalvaria is known to have a dismal prognosis and all the living cases with long-term follow-up are mentally retarded and physically disabled. Early and reliable antenatal diagnosis can reduce the economic, physical, and psychological burden associated with this fatal disease, especially in low-income countries.