The illnesses of Carlo di Ferdinando I de' Medici: a second opinion.

OBJECTIVES To offer a second opinion on the recently published retrospective diagnosis of Cardinal Carlo de' Medici (1596-1666), a prominent member of the grand ducal family then ruling Tuscany. METHODS Retrospective diagnosis of historical figures is difficult and at times controversial, even with modern technology. It is based on contemporaneous medical descriptions and historical reviews, inherited iconography, and rarely - as in the case of the Medici of Florence - skeletal assessment, completed with radiological, histological and even immunological studies. Modern clinical work is often complemented with a second opinion obtained from specialists in the relevant fields. It is this type of second opinion that our collaborative Australian and Italian team, comprised of an orthopaedic/spinal surgeon, a rheumatologist and two medical historians, now offers. RESULTS The authors concur with the first opinion's diagnosis of Klippel-Feil syndrome in Carlo de' Medici, but disagree with the diagnoses of tuberculosis (Pott's disease) and rheumatoid arthritis. We find evidence, instead, for a psoriatic-DISH arthropathy with involvement of Klippel-Feil syndrome. CONCLUSIONS A psoriatic-DISH arthropathy, previously described by the present authors as the 'Medici syndrome', was commonly found in the males of the primary branch of the family. The diagnosis of this condition in Cardinal Carlo de' Medici represents its first identification in a male of the secondary (grand ducal) branch of the family.