They are all more or less distorted in a discoidal manner, one by pressure over the frontal sinus, reducing the calvaria to a disk.
"The Arawack Language of Guiana in its Linguistic and Ethnological Relations"
Daniel G. Brinton
Metastatic cancer would appear to be conveyed by the blood stream; it may occur in a diffuse form-cancerous osteomalacia-softening the calvaria so that at the post-mortem examination it may be removed with the knife instead of the saw; or it occurs in a discrete or scattered form, and then the macerated skull presents a number of circular and oval perforations.
"Manual of Surgery Volume Second: Extremities--Head--Neck. Sixth Edition."
Alexander Miles Alexis Thomson