Page 161 - Concise Pathology for Exam Preparation ( PDFDrive )

146 SECTION I General Pathology

Q. Define and classify paraneoplastic syndromes.

Ans. A paraneoplastic syndrome is a symptom complex in patients with cancer that cannot
be explained either by local or distant spread of the tumour or by the elaboration of hor-
mones indigenous to the tissue of origin of the tumour.
Salient Features and Classification of Paraneoplastic Syndromes
• Paraneoplastic syndromes are seen in 10–15% patients with cancer and are important
to recognize because:
• They may be the earliest manifestation of occult or hidden cancer in some cases.
• They may manifest with signs and symptoms due to excessive production of that hormone.
• They may mimic metastatic disease.
• Paraneoplastic syndromes can be classified into:
• Endocrinopathies
• Nerve and muscle syndrome
• Dermatological disorders
• Vascular and haematological changes
• Bone and soft-tissue changes
Endocrinopathies
These are characterized by production of ectopic hormones or hormone-like substances
by cells of nonendocrine origin, eg, Cushing syndrome caused by ACTH or ACTH-like
substances produced by small cell carcinoma of lung, pancreatic carcinoma or neural tu-
mours; hypercalcemia (most common paraneoplastic syndrome) caused by excess
parathormone or related hormones (TNF-alfa, TGF-beta and IL-1) secreted by squamous
cell carcinoma of lung, carcinomas of breast, kidney, ovary and ATLL; and Carcinoid
syndrome produced by elaboration of serotonin and bradykinin by bronchial adenomas,
pancreatic carcinomas and gastric carcinomas.
Nerve and Muscle Syndrome
Examples include immunologically mediated myasthenia gravis in bronchogenic carcinoma,
and disorders of the central and peripheral nervous system seen in breast carcinoma.

Dermatological Disorders
Acanthosis nigricans may be a manifestation of carcinoma of the lung, uterus or stomach.
Dermatomyositis may be seen in bronchogenic and breast carcinoma.

Vascular and Haematological Changes
Tumour products (usually mucins that activate clotting factors) of pancreatic and broncho-
genic carcinoma can induce venous thrombosis (Trousseau sign). Nonbacterial throm-
botic endocarditis (due to hypercoagulability) is seen in many advanced cancers; and
anaemia may develop in association with thymic neoplasms (cause is unknown).

Bone and Soft-Tissue Changes
Hypertrophic osteoarthropathy and clubbing are common presenting symptoms of bron-
chogenic carcinoma (cause is unknown).

Q. Write briefly on laboratory diagnosis of cancer.
Ans. The modalities for laboratory diagnosis of cancer include:
1. Cytology
The main techniques used for cytological diagnosis are:
Direct
(a) Fine needle aspiration cytology (FNAC)
Image guided

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