The M-mode and 2-D echocardiographic features of an unusual case of a "pseudo-tumor" of the right ventricular outflow tract are reported. The unique pathologic findings of the pulmonary valve with congenital fenestrations and the clinical implications of this "pseudo-tumor" are discussed. Whenever calcification is noted at fluoroscopy to exist in a region or structure being evaluated by echocardiography, caution must be taken to avoid overestimating the size. Indistinct, dense reflectances without specific motion or appearance of a mass further helps to distinguish the reflectances from an actual structure of significance. Furthermore, all clinical, angiographic, and echocardiographic information must be interpreted together when either the angiogram or the echocardiogram is confusing and potentially misleading.