PMC5851333_01
Echocardiogram (a) shows an evident pedunculated mass, attached to the base of the anterior leaflet of the tricuspid valve and right ventricular septum extending into the right ventricular outflow tract. Gross pathology (b) shows a resected tumor, measuring 3.8 x 2.4 x 1.5 cm with infarction and degenerative changes. (c) H&E stain, 200x: stellate fibroblasts displaying small, elongated, dense nuclei and eosinophilic cytoplasm with indistinct cell borders enmeshed within a myxoid stroma. Extravasated red blood cells are seen adjacent to capillaries (arrows).
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fig1
The mass extended into the right ventricular outflow tract and caused marked obstruction of the pulmonary artery during systole (Figure 1). On cross section, a central cavitary area was noted, with fibrous material adherent to the inner lining and an average wall thickness of 0.8 cm (Figure 1). Microscopic sections revealed fibroblasts within a myxoid matrix and small, dense, elongated nuclei with inconspicuous mitoses and no atypia (Figure 1).
(a) Strongly positive CD34 staining in tumor sections under high magnification. (b) Low-power view shows strong CD34 staining in the tumor cells (lower right) with adjacent negatively staining cardiac tissue (upper left).
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fig2
Immunohistochemical staining was strongly positive for CD34 (Figure 2(a)) and negative for CD31, desmin, and smooth muscle actin. Sections demonstrated a successful transition between lesion and normal cardiac tissue at surgical margins (Figure 2(b)).