Rare cases of rare diseases: Re-examining early 20th century cases of anencephaly from the collection of the Moscow State University, Russia.

Objective: Documented cases of anencephaly were used to increase differential criteria of this rare disease.

Material: Two skulls from a 20-century documented medical collection at the Moscow State University diagnosed with anencephaly.

Methods: The skulls were evaluated based on macroscopic qualitative and quantitative morphological signs and X-ray analyses.

Results: Metric values and morphological features differ between the two cases of anencephaly noted in the collection and the published data based on normal fetal and neonatal remains.

Conclusions: Analyses of medical collections helps to increase the number of diagnostic criteria for recognition and diagnosis of anencephaly in archaeological skeletons.

Significance: Improvement in the recognition of skeletal alterations associated with anencephaly is key towards improving our understanding of rare diseases in the past.

Limitations: The fragility of skeletal elements of fetal and neonate individuals can complicate thorough analyses.

Suggestions For Further Research: Continue to identify cases of anencephaly cases in medical collections and in archaeological contexts.