Is it a cystic or a cyst-like condition? Discussing the etiology of an unusual large mandibular lesion in a Roman skeleton from Quinta da Torrinha/Quinta de Santo António (Almada, Portugal)

Cystic and cyst-like lesions of the jaw are a recurrent finding in routine dental radiography but not in paleopathology. This paper describes a large oval osteolytic cavity (23 × 14 mm) observed in the mandible of a middle-aged female unearthed from the Roman necropolis of Quinta da Torrinha/Quinta de Santo António (Almada, Portugal, 3rd-5th centuries AD). The lesion was located in the body of the mandible, inferior to the alveolus of the first left molar. The associated tooth exhibited a carious lesion that destroyed the tooth crown and exposed the pulp cavity. The osteolytic lesion presented inner smooth walls and sharped regular contours, surrounded by slight microporosity. Radiography revealed an unilocular lesion with well-defined contours and a thin opaque rim. The differential diagnosis considered several odontogenic and non-odontogenic conditions of the jaw. The size and shape of the cavity, the nature of its walls and contours, and the presence of a source of infection in the pulp is consistent with an odontogenic condition of inflammatory origin, probably a radicular cyst.