This treatise on tumors includes (p. 194) the first known description of an epidemic disease resembling scarlet fever. This was a malady prevalent in Italy, and was commonly called rossania or rossalia. Ingrassia was first to differentiate varicella (chicken pox) from scarlet fever (pp. 194-95). Digital facsimile from Google Books at this link.

Vesalius’s consilium to Ingrassia, dated Madrid, 1562, in which he clearly described the operation for empyema (pp. 92-98). Although treatment of empyema by surgery was referred to in classical times, it became unfashionable, and Vesalius seems to have been the first to revive the actual use of surgery for this illness. English translation in O’Malley, Andreas Vesalius of Brussels, Berkeley, Univ. of California Press, 1965, pp.398-402.

Ingrassia is by some accredited with the discovery of the stapes; he also observed the sound-conducting capacity of the teeth.