Page 248 - Textbook of Pathology, 6th Edition

232 i) Endocrine syndrome. Elaboration of hormones or solid tumours may be associated with secondary systemic
hormone-like substances by cancer cells of non-endocrine amyloidosis.
origin is called as ectopic hormone production. Some
examples are given below: PATHOLOGIC DIAGNOSIS OF CANCER
a) Hypercalcaemia. Symptomatic hypercalcaemia unrelated When the diagnosis of cancer is suspected on clinical
to hyperparathyroidism is the most common syndrome in examination and on other investigations, it must be
PNS. It occurs from elaboration of parathormone-like confirmed. The most certain and reliable method which has
substance by tumours such as squamous cell carcinoma of stood the test of time is the histological examination of biopsy,
the lung, carcinoma kidney, breast and adult T cell leukaemia though recently many other methods to arrive at the correct
SECTION I
lymphoma. diagnosis or confirm the histological diagnosis are available
b) Cushing’s syndrome. About 10% patients of small cell which are discussed in Chapter 2.
carcinoma of the lung elaborate ACTH or ACTH-like
substance producing Cushing’s syndrome. In addition, cases 1. Histological Methods
with pancreatic carcinoma and neurogenic tumours may be
associated with Cushing’s syndrome. These methods are based on microscopic examination of
c) Polycythaemia. Secretion of erythropoietin by certain properly fixed tissue (excised tumour mass or open/needle
biopsy from the mass), supported with complete clinical and
tumours such as renal cell carcinoma, hepatocellular investigative data. These methods are most valuable in
carcinoma and cerebellar haemangioma may cause arriving at the accurate diagnosis. The tissue must be fixed
polycythaemia. in 10% formalin for light microscopic examination and in
d) Hypoglycaemia. Elaboration of insulin-like substance by glutaraldehyde for electron microscopic studies, while quick-
fibrosarcomas, islet cell tumours of pancreas and frozen section and hormonal analysis are carried out on fresh
mesothelioma may cause hypoglycaemia. unfixed tissues.
ii) Neuromyopathic syndromes. About 5% of cancers are The histological diagnosis by either of these methods is
associated with progressive destruction of neurons made on the basis that morphological features of benign
throughout the nervous system without evidence of tumours resemble those of normal tissue and that they are
metastasis in the brain and spinal cord. This is probably medi- unable to invade and metastasise, while malignant tumours
ated by immunologic mechanisms. The changes in the are identified by lack of differentiation in cancer cells termed
neurons may affect the muscles as well. The changes are: ‘anaplasia’ or ‘cellular atypia’ and may invade as well as
peripheral neuropathy, cortical cerebellar degeneration, metastasise. The light microscopic and ultrastructural
General Pathology and Basic Techniques
myasthenia gravis syndrome, polymyositis. characteristics of neoplastic cell have been described in earlier
iii) Effects on osseous, joints and soft tissue. e.g. hyper- part of this chapter.
trophic osteoarthropathy and clubbing of fingers in cases of
bronchogenic carcinoma by unknown mechanism. 2. Cytological Methods
iv) Haematologic and vascular syndrome. e.g. venous These are discussed in detail in Chapter 11.
thrombosis (Trousseau’s phenomenon), non-bacterial Cytological methods for diagnosis consist of study of cells
thrombotic endocarditis, disseminated intravascular coagu- shed off into body cavities (exfoliative cytology) and study
lation (DIC), leukemoid reaction and normocytic normo- of cells by putting a fine needle introduced under vacuum
chromic anaemia occurring in advanced cancers. Auto- into the lesion (fine needle aspiration cytology, FNAC).
immune haemolytic anaemia may be associated with B-cell
malignancies. i) Exfoliative cytology. Cytologic smear (Papanicolaou or
Pap smear) method was initially employed for detecting
v) Gastrointestinal syndromes. Malabsorption of various dysplasia, carcinoma in situ and invasive carcinoma of the
dietary components as well as hypoalbuminaemia may be uterine cervix. However, its use has now been widely
associated with a variety of cancers which do not directly extended to include examination of sputum and bronchial
involve small bowel. washings; pleural, peritoneal and pericardial effusions; urine,
vi) Renal syndromes. Renal vein thrombosis or systemic gastric secretions, and CSF. The method is based on
amyloidosis may produce nephrotic syndrome in patients microscopic identification of the characteristics of malignant
with cancer. cells which are incohesive and loose and are thus shed off or
vii) Cutaneous syndromes. Acanthosis nigricans charac- ‘exfoliated’ into the lumen. However, a ‘negative diagnosis’
terised by the appearance of black warty lesions in the axillae does not altogether rule out malignancy due to possibility of
and the groins may appear in the course of adenocarcinoma sampling error.
of gastrointestinal tract. Other cutaneous lesions in PNS ii) Fine needle aspiration cytology (FNAC). Currently,
include seborrheric dermatitis in advanced malignant cytopathology includes not only study of exfoliated cells but
tumours and exfoliative dermatitis in lymphomas and also materials obtained from superficial and deep-seated
Hodgkin’s disease. lesions in the body which do not shed off cells freely. The
viii) Amyloidosis. Primary amyloid deposits may occur latter method consists of study of cells obtained by a fine
in multiple myeloma whereas renal cell carcinoma and other needle introduced under vacuum into the lesion, so called