SUMMARY Two cases of primary malignant cardiac neoplasms are presented. The first, an angiosarcoma of the right atrium, developed in a 44-year-old housewife, who survived 23 days from the time of presentation; diagnosis was made at necropsy. The second, an embryonal rhabdomyosarcoma of the right ventricle, developed in a 17-year-old student; diagnosis was made by angiocardiography.He underwent surgery and cytotoxic and irradiation therapy and died 14 months later.Primary malignant cardiac neoplasms are very rare; sarcomata form the vast majority. In classifying these tumours, the first step is to consider whether the tumour is of vascular or myogenic origin; in this paper we describe one example of each. The first, an angiosarcoma of the right atrium, presented little difficulty in histological classification at necropsy. Although the case had not been diagnosed during life, the symptoms were strikingly similar to those of previously recorded cases. In the second case, a cardiac tumour was diagnosed during life by angiocardiography. Histological diagnosis here was more difficult. The finding of beaded intracytoplasmic filaments greatly supports the view that the tumour is of myogenic origin, although they are not pathognomonic ultrastructural features of this tumour (Toker, 1968). The filaments are in fact identical with those seen in the chick myoblast (Bauer and McGavran, 1974).
Material and methodsMaterial from case 1 was obtained at necropsy. Tissue for light microscopy was embedded in paraffin. Sections were stained with haematoxylin and eosin and with Gordon and Sweet's reticulin stain using a neutral red counterstain. Material for electron microscopy was fixed for 8 hours in 5% glutaraldehyde followed by overnight washing in cacodylate buffer. It was then osmicated, rinsed in distilled water, stained with 3% uranyl acetate, dehydrated with acetone, and embedded in Spurr resin. SectionsReceived for publication 7 December 1978 were cut and stained by 0 3 % lead citrate (Reynold's method). Sections were examined in a Jeol 100 S transmission electron microscope.Material from case 2 was obtained at necropsy, embedded in paraffin, and stained with haematoxylin and eosin, Mallory's phosphotungstic acidhaematoxylin, and Heidenhain's iron haematoxylin. Tissue for electron microscopy was obtained by dewaxing paraffin-embedded material with xylene. It was then hydrated in descending grades of alcohol, rinsed in distilled water, washed in cacodylate buffer overnight, and osmicated. The remainder of the procedure was as described for case 1.
CASE 1A 44-year-old housewife was admitted with nausea, anorexia, epigastric fullness, and flatulence. She claimed that these symptoms had been present for six months and had worsened in the few days before admission.A chest x-ray on admission showed cardiomegaly and a left pleural effusion. An