Acalvaria in historical records.

BACKGROUND: Acalvaria describes a rare defect of the cranial vault marked by the absence of cranial bones or the dura mater, whereas the brain, cranial base and facial bones remain intact. Although it is considered as a perinatal lethal malformation, some cases of surviving newborns have also been documented. In historical sources and medical literature, it is often difficult to distinguish it from Acrania, or it is incorrectly referred to as Anencephaly or other related terms. Due to its rarity in modern case reports, this article investigates whether it can be found in historical records. MATERIAL AND METHODS: Written sources and material culture from Antiquity, as well as texts and illustrations from the Early Modern Period and the 19th Century, with a focus on Dutch- and German-speaking areas, are examined using the historical-critical method. RESULTS: Ancient authors do not mention this type of malformation, even though they were deeply concerned with stillbirths and possessed knowledge of skull development. The poor preservation of archaeological finds from Antiquity prevents the clear identification of potential cases. In the Early Modern Period, collections and pamphlets were printed to illustrate cases with related malformations. With the emergence of the discipline of Teratology, classification systems were established, accompanied by a multiplication of new terms. CONCLUSION: The presented cases could meet the definition of Acalvaria. However, without an autopsy and relying solely on descriptions and drawings, it is practically impossible to diagnose Acalvaria with certainty.