Discussion
The differential diagnosis for aortic valve mass includes papillary
fibroelastoma, endocarditis, Lambl’s excrescence. Our case highlights
the challenge in diagnosing Whipple’s endocarditis. Our patient
presented with TIA from a cardiac embolic cause without arthralgia, the
most common symptom of Whipple endocarditis, and no systemic signs of
infection such as fever. However, the majority of cases described in the
literature reported aortic valve lesions in the absence of fever
[6]. Furthermore, it is crucial to recognize that T
whipplei endocarditis differs from classic Whipple disease, which tends
to involve multiple organ systems. Our case also highlights the
importance of molecular diagnostics in the diagnosis of that T
whipplei endocarditis. Pathologically, our patient’s lesion resembled
an Amorphous Cardiac Tumor, which rarely arises in the aortic valve. In
fact, there have been four cases of CAT with isolated involvement of the
aortic valve [7-10]. Several features made CAT an unlikely diagnosis
in our patient. Even though pathogenesis of CAT is poorly understood, a
systematic review revealed that 21% of CAT cases were found in patients
with end-stage renal disease [11], which our patient did not have.
Furthermore, there is a female predominance, and the majority of
reported CAT cases involve the left ventricle the mitral valve, with
only a few reported cases arising from the aortic valve [12]. A
histopathologic diagnosis of T whipplei endocarditis, however can
be made with periodic acid-Schiff (PAS) staining. Although more commonly
performed on duodenal biopsies in the diagnosis of classical whipple’s
disease, PAS-positive macrophages from an extracted valvular lesion has
been reported [6,13,14]. For T whipplei endocarditis,
molecular analysis with 16S rRNA PCR following surgical resection of the
valvular lesion is currently the preferred diagnostic approach.
Unfortunately, 16S rRNA amplification from blood specimens is not
sensitive [15].