Page 223 - Textbook of Pathology, 6th Edition

Besides acute leukaemias, other tumours in infancy and 207
childhood are: neuroblastoma, nephroblastoma (Wilms’
tumour), retinoblastoma, hepatoblastoma, rhabdomyo-
sarcoma, Ewing’s sarcoma, teratoma and CNS tumours.
5. SEX. Apart from the malignant tumours of organs
peculiar to each sex, most tumours are generally more CHAPTER 8
common in men than in women except cancer of the breast,
gall bladder, thyroid and hypopharynx. Although there are
geographic and racial variations, cancer of the breast is the
commonest cancer in women throughout the world while lung
cancer is the commonest cancer in men. The differences in
incidence of certain cancers in the two sexes may be related
to the presence of specific sex hormones. Neoplasia

B. Chronic Non-neoplastic (Pre-malignant) Conditions
Premalignant lesions are a group of conditions which
predispose to the subsequent development of cancer. Such Figure 8.16 Carcinoma in situ of uterine cervix. The atypical
conditions are important to recognise so as to prevent the dysplastic squamous cells are confined to all the layers of the mucosa
subsequent occurrence of an invasive cancer. Many of these but the basement membrane on which these layers rest is intact.
conditions are characterised by morphologic changes in the ii) Cirrhosis of the liver has predisposition to develop
cells such as increased nuclear-cytoplasmic ratio, hepatocellular carcinoma.
pleomorphism of cells and nuclei, increased mitotic activity, iii) Chronic bronchitis in heavy cigarette smokers may
poor differentiation, and sometimes accompanied by chronic develop cancer of the bronchus.
inflammatory cells. iv) Chronic irritation from jagged tooth or ill-fitting denture
Some examples of premalignant lesions are given below:
may lead to cancer of the oral cavity.
1. Carcinoma in situ (intraepithelial neoplasia). When the v) Squamous cell carcinoma developing in an old burn scar
cytological features of malignancy are present but the (Marjolin’s ulcer).
malignant cells are confined to epithelium without invasion
across the basement membrane, it is called as carcinoma C. Hormones and Cancer
in situ or intraepithelial neoplasia (CIN). The common sites Cancer is more likely to develop in organs and tissues which
are as under: undergo proliferation under the influence of excessive
i) Uterine cervix at the junction of ecto- and endocervix hormonal stimulation. On cessation of hormonal stimulation,
(Fig. 8.16) such tissues become atrophic. Hormone-sensitive tissues
ii) Bowen’s disease of the skin developing tumours are the breast, endometrium,
iii) Actinic or solar keratosis myometrium, vagina, thyroid, liver, prostate and testis. Some
iv) Oral leukoplakia examples of hormones influencing carcinogenesis in
v) Intralobular and intraductal carcinoma of the breast. experimental animals and humans are given below:
The area involved in carcinoma in situ may be single and 1. OESTROGEN. Examples of oestrogen-induced cancers
small, or multifocal. As regards the behaviour of CIN, it may are as under:
regress and return to normal or may develop into invasive i) In experimental animals. Induction of breast cancer in
cancer. In some instances such as in cervical cancer, there is mice by administration of high-dose of oestrogen and
a sequential transformation from squamous metaplasia, to reduction of the tumour development following oophorec-
epithelial dysplasia, to carcinoma in situ, and eventually to tomy is the most important example. It has been known that
invasive cancer. associated infection with mouse mammary tumour virus
2. Some benign tumours. Commonly, benign tumours do (MMTV, Bittner milk factor) has an added influence on the
not become malignant. However, there are some exceptions development of breast cancer in mice. Other cancers which
e.g. can be experimentally induced in mice by oestrogens are
i) Multiple villous adenomas of the large intestine have high squamous cell carcinoma of the cervix, connective tissue
incidence of developing adenocarcinoma. tumour of the myometrium, Leydig cell tumour of the testis
in male mice, tumour of the kidney in hamsters, and benign
ii) Neurofibromatosis (von Recklinghausen’s disease) may as well as malignant tumours of the liver in rats.
develop into sarcoma.
ii) In humans. Women receiving oestrogen therapy and
3. Miscellaneous conditions. Certain inflammatory and women with oestrogen-secreting granulosa cell tumour of
hyperplastic conditions are prone to development of cancer, the ovary have increased risk of developing endometrial
e.g. carcinoma. Adenocarcinoma of the vagina is seen with
i) Patients of long-standing ulcerative colitis are predis- increased frequency in adolescent daughters of mothers who
posed to develop colorectal cancer. had received oestrogen therapy during pregnancy.