Exploring a Calcified Tissue from the 19th century Carmo Burial Site (Porto, Portugal): Differential Diagnosis Using Nano-CT Imaging

An adult individual of indeterminate sex was excavated from the burial site of the Third Order of Our Lady of Carmo in Porto (Portugal), which was in use from 1801 to 1869. The individual is part of a large assemblage (circa 490 individuals, including adults and subadults) excavated between 2006 and 2007, currently under analysis. An ovoid-shaped mass (dimensions: 27x26x18mm) was curated with the sacrum by excavators, its precise in-situ location was not recorded. The differential diagnosis was conducted based on macroscopic examination, SKYSCANTM 2214 multiscale X-ray nano-CT imaging, and X-ray diffraction. The smooth external appearance is characterised by folds and sulci with some vascularisation evident; nano-CT imaging revealed dense calcification throughout, arranged in a lobular structure with some hollow spaces. X-ray diffraction confirmed the crystalline structure of the tissue is consistent with hydroxyapatite. Drawing on palaeopathological and clinical literature, the differential diagnosis considered 12 possible aetiologies resulting in the following most likely diagnosis: calcified (uterine) leiomyoma, calcified amputated ovary and calcified fibroadenoma. Clinical diagnosis of calcified tissues strongly utilises relations to so tissue anatomy which are unavailable in skeletal remains. This limitation is compounded by the precise in situ location not being recorded. Nonetheless, the results demonstrate the utility of the diagnostic approach presented here to narrow down the differential diagnosis. The study thereby expands palaeopathological knowledge of frequency and structure of calcifications, as well as contributing palaeoradiographic imaging to the literature, and highlights the importance of careful field data collection. Future research on other masses recovered in situ with individuals from the same site will enable comparison and holistic interpretation of health in the community. Paper presented in 24th European Meeting of Paleopathology Association, 2024