PRIMARY MALIGNANT GROWTH OF THE KIDNEY 16 
pelvic lining. The convex border of the crescent is formed by the above-mentioned strip 
of kidney tissue, except where the spherical column of new growth bulges into the pelvis. 
The pelvic walls are in contact, but the extent of the lining points to there 
having been some dilatation. The ureter is patent. 
The section of the growth shews a division into irregular lobules, but there are 
also septa marking off four lobes, one forming the apical portion of the mass, one 
the central and much the largest portion, and two smaller on the inferior and outer 
aspect of the central lobe. The upper lobe can be lifted off the central lobe by a 
slight blunt dissection on the anterior and outer parts, but posteriorly it is blended 
with the latter. The lower two small lobes are less perfectly differentiated. The 
lobes differ in naked eye structure ; the central mass appears to consist largely 
of fat with comparatively scanty interstitial matter ; the upper lobe is greyish in 
colour as contrasted with the yellow of the central lobe, and no fatty tissue is 
appreciable ; the same applies to the most external of the other two lobes, while the 
fourth resembles the central. 
Distributed throughout the growth are many small cysts, the largest about 
the size of the head of an ordinary tin tack. 
The relations of the new growth to the remains of the renal tissue enable one 
to decide with certainty its seat of origin. 
The relation of the growth to the lining of the pelvis, and more especially 
the position of that out-growth which lies between pelvis and cortex at the lower pole 
of the growth, shows that it originated in the renal tissue itself. 
The position of the artery and the ureter show that it originated above 
the hilum, and about centrally as regards the antero-posterior dimension. Thirdly, 
the position of the renal remains enables one to decide that the point of origin 
was on the inner face of the kidney, the growth, by extension, displacing the 
kidney downwards and outwards, or rather causing it to rotate through a segment 
of a circle, of which the hilum is the centre, the direction of rotation being from right 
to left. The seat of origin was therefore in the substance of the kidney, and in the 
upper and inner quadrant. As stated above, the upper edge of the renal tissue on 
the outer aspect of the growth is sharply defined, and it can be dissected off without 
tearing through anything except fibrous bands. This first suggested the idea that the 
growth was extra-renal in origin, but the other relations negatived this. Evidently 
the extension of the growth was first in an upward direction, subsequently, meeting 
the resistance of the capsule, the pressure would be exerted in an outward and 
downward direction. 
The well-marked lobulation probably has relation to the original lobulation of 
the kidney. The lobe which forms the apex of the growth is so distinctly marked 
off, that it was thought to represent the adrenal body. Histologically, however, this 
was not confirmed. 
