On the basis of 20 cases of pure xanthoma tuberosum multiplex and data collected from
the literature, the authors outline the clinical, biological, genetic and therapeutic
characteristics of this affection.
Clinically, the emphasis is on the exclusiveness of tuberous xanthomas (with the exception
of borderline cases which involve a single small tendinous xanthoma), the fact that
they are as persistent as the biological anomalies, and the importance and early occurrence
of atheromatous complications.
The characteristic biological feature is the truly intermediate position of the chemical
as well as the electrophoretic lipid pattern between that of essential hypercholesteraemia
and that of endogenous hyperglyceridaemia. This leads the author to a rejection of
typological rigidity, which might preclude a comparison (so desirable in this context)
of different electrophoretic patterns, specifically type III and type II + IV. The
condition involves truly mixed hyperlipidaemia - both hypercholesteraemia and hyperglyceridaemia
— which produces a pattern quite different from type II or essential hyperlipaemia.
Genetically, it seems likely that pure xanthoma tuberosum multiplex, as expressive
of mixed hyperlipidaemia, is a homologue of cutaneotendinous xanthoma as expressive
of essential hypercholesteraemia, that is to say: a homozygous cumulate form of a
minor defect, generally transmitted as an autosomal dominant.
The above criteria, together with the excellent therapeutic response to a combination
of dietetic measures (glucide restriction or total caloric restriction, and substitution
of unsaturated fatty acids) and medication with aryloxybutyrate derivatives, characterize
pure xanthoma tuberosum multiplex as a distinct pathological entity which is the prototype
or reference model of mixed hyperlipidaemia.