Button Hamartoma
From bonepath
“Button hamartoma” is the name Eshed and colleagues (2002) suggest for the bony nodules that mark the ectocranial vault. In the paleopathology/bioarcheology literature, these are also called “button-“ and “ivory osteomata” (e.g. Roberts and Manchester 2005). The difference between ‘hamartoma’ and ‘osteoma’ is not simply semantic, but refers to the etiology of these bony bumps. Osteoma is an actual benign, bony tumor, whereas hamartoma is a general developmental aberration in which the component parts of tissue do not form in the proper proportion (Eshed et al. 2002). When this malformation occurs in cranial bone, the aberration superficially resembles a tumor. It is not clear why button harmartomata occur, and Eshed and colleagues posit an evolutionary etiology: relatively rapid neurocranial growth in humans (because of selection for large brain size) has decoupled cranial and overall skeletal growth such that our cranial vaults may be hyperplastic at older ages (the non-human primates in the sample exhibited an extremely low frequency of hamartoma).
Eshed and colleagues (2002) found that these hamartomata occurred at a very high frequency, at least 35% in the Haman-Todd skeletal collection. This collection is composed of American ‘blacks and whites,’ and hamartomata affected each of these groups, as well as each of the sexes, equally. Hamartomata appear to increase in frequency with age. These bony growths tend to occur most often on the parietal or frontal bones, and can occur alone or en masse. There are no health-related symptoms of hamartoma, aside possibly from aesthetics, so hamartomata are probably underrepresented clinically.
[edit] Examples from Ford Collection
[edit] References
Eshed V, Latimer B, Greenwald CM, Jellema LM, et al. 2002. Button osteoma: its etiology and pathophysiology. Am J Phys Anthropol 118:217-30
Roberts C, Manchester K. 2005. The Archaeology of Disease. Ithaca: Cornell University Press
