Expansion
Effects not explained by the tumour mass, its metastases or its hormones of origin
Expansion
Endocrine
- SIADH: small cell lung carcinoma
- Ectopic ACTH: small cell lung carcinoma, carcinoid. Rapid onset Cushing with marked hypokalaemic alkalosis and pigmentation
- Hypercalcaemia: PTHrP from squamous cell lung carcinoma, renal and breast cancer; also from bone metastases and from myeloma
- Hypoglycaemia from insulin-like growth factor 2
Neurological
- Lambert-Eaton myasthenic syndrome: antibodies to presynaptic calcium channels, small cell lung carcinoma
- Cerebellar degeneration, limbic encephalitis, sensory neuronopathy
Haematological: polycythaemia (renal cell carcinoma, hepatocellular carcinoma, cerebellar haemangioblastoma), migratory thrombophlebitis (Trousseau sign, pancreatic carcinoma), DIC.
Dermatological: acanthosis nigricans (gastric), dermatomyositis, acquired ichthyosis.
Other: clubbing and hypertrophic pulmonary osteoarthropathy, membranous nephropathy, cachexia.
The clinical importance is that these may be the presenting feature, appearing before the tumour is detectable, and they may resolve with treatment of the primary and recur with relapse.