2. The shock of a solid tumor is not markedly stronger than that of the heart (Balfour).
3. There is no accentuation of the second heart sound (Walshe), nor bruit of a booming character (Hayden).
4. In the sphygmographic tracing of a tumor-pulse the up-stroke is never sloping, and the percussion wave remains well marked.
5. Variations in the position and size of a tumor, and also in the pressure phenomena, are important. An aneurism varies constantly in its size and in its mural tension; hence all its signs vary correspondingly; whereas with a solid tumor in the mediastinum the phenomena are more constantly progressive. An aneurism which is visible and palpable upon the external chest-walls will sometimes recede within the thorax, whereas solid or cancerous tumors never act thus.
Abscess of a gland in the episternal notch may closely simulate aneurism of the innominate. Mahomed and Golding-Bird report such a case. The imitation was so close in this case as to balk a number of very careful observers, and no absolute diagnosis was reached until the sudden rapid increase of the growth and of acute superficial inflammatory symptoms revealed the probability of pus. The abscess was supposed to result from the pressure of a collar-button. A companion case was reported by the same author where an actual aneurism of the innominate presented such neutral signs that no diagnosis was reached until the patient was etherized and an exploratory incision was made down to the sac. It is well to remember that an aneurism may rise and fall with deglutition and with coughing and straining when it is adherent to the trachea. A case is reported of a very vascular sarcoma attached to the manubrium sterni and projecting into the episternal notch, which presented the double murmur, pulsation, and pressure symptoms of an aneurism, and was diagnosed as such, the mistake being discovered only at the autopsy. In such very obscure cases I know of no reliable or distinctive signs on which a diagnosis may be established: the only resort seems to be to await developments. In process of time the appearance of cancerous growth in other parts of the body will often throw light upon a thoracic tumor. Occasionally aneurism of the aorta may simulate insufficiency of the aortic valves. Guttmann reports a case which presented all the classical symptoms of aortic regurgitation and none of aneurism. The autopsy revealed a large aneurism of the ascending aorta and the aortic valves intact. The aorta itself was notably dilated throughout, and it is probable that the change in the arterial walls affected the proper systolic contraction of the aortic orifice, so that insufficiency resulted. Chronic endarteritis of the aorta may produce aneurismal signs. Dujardin-Beaumetz reports a case where there were contraction of the left pupil, sudden reddening of the left side of the face, transient aphonia, intermittent dyspnoea, suppression of the left radial pulse, and a double souffle along the track of the aorta; and yet the autopsy revealed simply endarteritis of the transverse portion of that vessel, without the least dilatation. Many of the symptoms of this case could be explained by the extension of the inflammation to the sympathetic nerves.
Many aneurismal signs connected with the voice, eye, and vascular supply of the heart may be produced by the implication of either vagus in neighboring inflammation. Chronic empyema of the left side will sometimes pulsate synchronously with the heart and simulate aneurism. The following points are important:
1. Such pulsations occur only on the left side.
2. There is always a disproportion between the pulsations, which are feeble, and the extent of dulness, which is large.
3. There is absence of expansile pulsations.
4. There is usually ample evidence of the presence of a pleuritic effusion, displacement of the heart, etc.