Mastoid osteoma in a prehispanic cranium (1390 A.D.) from Northern Chile

Objective: Osteomas are slow-growing benign tumors that can affect the skull, most frequently the parietal and frontal. Temporal bone osteomas are more common in the external acoustic meatus and exceptional in the mastoid region. The rarity of mastoid osteomas is confirmed by the fact that very few cases have been reported in the clinical and paleopathological literature. The aim of this paper is to report a new paleopathological case of mastoid tumor in a Pre-Hispanic adult cranium. Materials: The skull derives from the Chunchuri (today Dupont-1 site) Pre-Hispanic site in Northern Chile (1390 A.D). Methods: Macroscopical examination and high-resolution tomography were used to assess the cranium. Results: The CT scan revealed a well demarcated lesion suggestive of a mastoid osteoma. Conclusions: This case adds new evidence regarding the antiquity of primary neoplasms in ancient populations and reinforces the importance of high resolution imaging in paleopathological research. Significance: Due to the antiquity of the remains this is probably the oldest reported case of mastoid osteoma. Limitations: The patrimonial nature of the remains did not allow histopathological studies. Suggestions for Further Research: Further intensive review of archeological skeletal collections is needed to better understand the epidemiology of neoplastic lesions in past populations.