Figure 2. A large homogenous mass like thickness in RA (4.87 *1.66 cm),
abnormal thickening post IAS is seem to be infiltrative process
The patient’s younger brother, currently 27 years old, was found to be
homozygous for a pathogenic variant in the SLC29A3 gene. Laboratory
results showed elevated erythrocyte sedimentation rate (ESR) and
reactive protein (CRP) levels. Echocardiography revealed a large
heterogeneous mass-like thickness in the right atrium. CMR confirmed an
infiltrative mass in the RA roof and atrioventricular (AV) groove with
the encasement of the RCA and SVC (Figure 3 A-E). Later, EDC emerged as
the leading differential diagnosis based on MRI tissue characterization
criteria.
Furthermore, a CT scan showed mild abdominal aortic wall thickening,
bilateral renal cortical and peri-renal soft tissue infiltration, and
mild diffuse osteopenia and wedge deformity of the thoracolumbar
vertebra, all consistent with EDC. Kidney biopsy revealed mixed
inflammatory cell infiltration containing some histiocytes, supporting
the diagnosis of non-Langerhans cell histiocytosis.