Skin (cutaneous) syndromes
Various skin conditions are associated with some cases of lung cancer. These conditions are thought to be caused by aberrant behavior of white blood cells and their antibodies reacting either to the tumor or to substances produced by the tumor:
• Chronic inflammation of the skin (dermatomyositis) often occurs in conjunction with muscle and subcutaneous tissue inflammation.
• Gray-black warty patches on the elbows, knees, armpits, or groin (acanthosis nigricans)
• Itching (pruritis)
• Chronic red patches (erythema multiforme)
• Dark patches (hyperpigmentation)
• Hives (urticaria)
• Scaly patches (scleroderma)
• New tissue growth in fingertips (digital clubbing), a widening and rounding of the fingertips and nails and, when fingers are viewed from the side, a loss of normal indentation where the fingernail emerges from the skin.
Musculoskeletal syndromes
Certain lung tumors can cause the following symptoms by producing hormones or causing unusual tissue growth:
• Inflamed muscles, skin, and subcutaneous tissue (polymyositis-dermatomyositis) is thought by some researchers to be a araneoplastic syndrome. Some researchers believe this finding justifies intensive testing for presence of malignancy;
other studies have found no link between malignancy and this syndrome.
• Abnormal bone growth in certain bones, especially fingertips (hypertrophic osteoarthropathy). This abnormal bone growth is visible on x-ray and bone scans and might be associated with bone or joint pain.
• Softening of the bones (osteomalacia) • Various painful or dysfunctional muscular symptoms
(myopathy)