The writers have a long and honorable identification with the concept of polymyalgia rheumatica. It is little wonder that they are disturbed by the questions raised. However, I believe we are in agreement that the concept of polymyalgia rheumatica needs to remain rigidly defined and should not admit instances of simultaneous synovitis.
The taxonomy of rheumatic diseases remains primarily syndromic. Symptoms and signs define the disease, and the disease is defined by the symptoms and signs that produce it. Some flexibility is necessary, as causes are generally unknown, and an undue rigidity and assertion of the divine right of diagnostic terms have as little merit as a contemporary claim of the divine right of kings.
Rheumatology, like much of medicine, is still full of dangling comparatives. A statistic is cited in support of a specific association or causation; we do not know how often this particular feature occurs