M. Y. MANGRULKAR                                         183

clusters of cells and the formation of glandular structures resembling short
and long, hollow tubules or alveoli. By suitable staining methods, connective
tissue fibrils could be demonstrated ramifying in the cell-masses. Minute
connective tissue streaks could also be seen between the tubules (Plate XVI,
fig. 1). Such minute blood vessels as were carried by these streaks appeared
delicate, with evidence of haemorrhage resulting in effusion of blood into the
tubules.

The cell clusters consisted of round cells or spindle-cells, the nuclei of
which were on. the whole vesicular. The presence, size and number of nucleoli.
were inconstant. The size of the cells varied within a narrow range.

It was not difficult to discover fields illustrating, as mentioned above,
the differentiation of such cell masses into glandular structures, mitotic pro-
liferation being evident in both situations. By ingrowths of connective
tissue smaller cell clusters were formed which gradually changed from a solid
mass or cord into a hollow glandular structure, the lining cells of which showed
a tendency to become arranged in a single layer. More often, however, by
active proliferation rather than by imperfect differentiation, the lining of the
glands presented a pseudostratified appearance like that of tracheal mucosa.
The cells were somewhat columnar, disposed perpendicularly to the axis of the
gland ; the cytoplasm appeared finely granular. Mitotic figures were frequent
and the entire picture (Plate XVII, fig. 1) bore a close resemblance to certain
types of adenocarcinoma. No secretion was present in the glands. Capillary
haemorrhages between and in the tubules were common in areas where the
glands were closely packed together.

In medium-sized metastatic tumours which appeared to have undergone
apparently little modification in their true neoplastic structure, an active
growth of the glandular moiety was seen, the tubules being arranged radially,
at once recalling the structure of the adult kidney, although recognisable
glomerular formations were not present in the neoplasm. It must be stressed
here that, on the whole, this type of histology was a very prominent feature
of the tumours under report.

The lining of the glands was occasionally seen to form papilliform pro-
jections into the lumen. This feature, however, stopped short of the formation
of a typical papillary adenomatous structure.

At places either due to pressure of the better developed connective tissue
strands, or due to lack of differentiation of the glandular structure, cell cords
or clusters were encountered either singly or in groups, squeezed, as it were,
between the connective tissue strands, thus presenting a picture of marked
resemblance to a scirrhous cancer.

In sections of the large tumour, hyaline change was noticed in the connec-
tive tissue.