Page 218 - Textbook of Pathology, 6th Edition

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SECTION I

Figure 8.13 Gross appearance of haematogenous metastases at common sites.

as with lymphatic metastases. Important examples are Microscopically, the secondary deposits generally
vertebral metastases in cancers of the thyroid and prostate.
reproduce the structure of primary tumour (Fig. 8.14, B).
Grossly, blood-borne metastases in an organ appear as However, the same primary tumour on metastasis at
multiple, rounded nodules of varying size, scattered different sites may show varying grades of differentiation,
throughout the organ (Fig. 8.13). Sometimes, the apparently due to the influence of local environment
metastasis may grow bigger than the primary tumour. At surrounding the tumour for its growth.
times, metastatic deposits may come to attention first
without an evident primary tumour. In such cases search 3. SPREAD ALONG BODY CAVITIES AND NATURAL
for primary tumour may be rewarding, but rarely the PASSAGES. Uncommonly, some cancers may spread by
General Pathology and Basic Techniques
primary tumour may remain undetected or occult. seeding across body cavities and natural passages. These
Metastatic deposits just like primary tumour may cause routes of distant spread are as under:
further dissemination via lymphatics and blood vessels i) Transcoelomic spread. Certain cancers invade through
(Fig. 8.14, A). the serosal wall of the coelomic cavity so that tumour

Figure 8.14 Metastatic sarcoma lung. A, Sectioned surface of the lung shows replacement of slaty-grey spongy parenchyma with multiple,
firm, grey-white nodular masses, some having areas of haemorhages and necrosis. B, Microscopic appearance of pulmonary metastatic deposits
from sarcoma.