l62 
THOMPSON YATES LABORATORIES REPORT 
Histology — -There is a certain uniformity throughout the whole tumour in that 
the various elements of which it is composed are present in all parts, but they are 
very unequally distributed. 
Central Mass — Fatty tissue predominates. Other elements appear as scattered 
islands and tracts in the sections. The fat is enclosed in a fine connective tissue mesh. 
Strands of striped muscle cells run in all directions. The striation of many 
of the cells is easily seen, but in many also it cannot be distinguished. The latter 
cells are for the most part uninucleated and tapering, the striated cells are stouter and 
often shew more than one nucleus. All are evidently young cells not far advanced 
in development. Strands of young fibrous tissue are also present, but more scantily 
than the muscle tissue ; the cells are narrow, with long tapering nuclei. 
These bundles of muscle and fibrous tissue can all be traced to connections 
with the cells of what I will for the present call the Pseudo-cystic formations. 
The larger of these bodies are easily seen macroscopically as crateriform 
depressions on section ; other forms of them are represented by white dots. 
The histology of these bodies is as follows : — 
The smallest and youngest consist of — 
1 A limiting layer of flattened cells, of connective tissue type. 
2 A mass of polyhedral cells within, with large nuclei staining deeply. 
From this simple structure they can be traced through a series of changes 
partly degenerative, partly proliferative. 
In the first stage of these changes the cells centrally placed develop a squamous 
cell body, oval or irregular in shape, and the nuclei stain less distinctly. The cell 
bodies are hyaline, and between them branches a delicate reticulum (Fig. I). 
It is convenient to follow these central cells in the first place, and then to con- 
sider those peripherally placed. 
The squamous cells next become somewhat shrunken, the nuclear outlines are 
blurred and the intercellular reticulum is more distinct. The cellular layers then split 
up into ribbons and separate from one another, and the reticulum consists of strong 
fibrils circularly arranged (Fig II). 
Lastly, the central parts are represented by a (Fig III) whorl-like arrangement 
of flaky fibrils, the cells having disappeared entirely. In some specimens even this has 
disappeared, and the structure is a true cyst, containing occasionally some granular debris. 
These changes are of course degenerative. The evolution of the peripheral 
cells is, however, in the direction of proliferation. The limiting layer is usually quite 
indistinctly marked off from the cells immediately within ; these are in many specimens 
set endwise on the outer layer and are cubical in shape, but this arrangement is not 
constant. From these peripheral cells to a greater or less degree in all specimens, 
tracts and columns of cells originate and pass out in all directions into the fatty matrix. 
These cells are round cells of sarcomatous type. Where they take origin 
