By Gary M. White, MD
Flushing shown here. Courtesy James Steger, MD
Carcinoid syndrome is caused by a tumor that secretes 5HIAA (5 hydroxy-indole-acetic acid) which causes flushing. The most common pattern is to have a tumor arise in the gut and metastasize to the liver with typical fibrotic heart lesions and induration of the lower legs [BJD 1993;129;222]. One may check the urine for 5HIAA.
Flushing, diarrhea and abdominal pain are characteristic. The flushing may last minutes or days and be facial, total body or geographic. It may be provoked by alcohol, emotions or certain foods (e.g. spices, chocolate, cheese, avocados, plums, walnuts, red sausage, red wine). 80% of patients flush, 70% have a secretory diarrhea, 40% have right sided heart disease (e.g. pulmonary stenosis, tricuspid regurgitation), 20% dyspnea, 17% wheezing, 7% myopathy, and 5% skin pigmentation [NEJM 1992;326;472]. Induration of the skin may occur.
Rarely, in extensive disease, pellagra-like skin lesions can also develop as the carcinoid tumor consumes tryptophan, leaving little for the daily niacin requirement. A specific variant of scleroderma affecting predominantly the legs has been described [Br J Dermatol 2005;152;71].
If the patient suffers from repeated episodes of flushing over years, a fixed redness (e.g. telangiectasias) of the upper chest and face may develop.
Metastatic cutaneous carcinoid occurs rarely--anywhere on the skin [JAAD 1996;35;997]. There are either single or multiple cutaneous nodules that may ulcerate. They may be firm and tender and brown, red or violaceous.
Workup should be performed by a specialist. Tests used include urine 5HIAA and serum serotonin and chromogranin-A (the vasoactive intestinal glycopeptide). Blood serotonin level is helpful when the urinary 5-HIAA level is equivocal as patients with carcinoid syndrome have very high blood levels of serotonin.
For metastatic or unresectable carcinoid, octreotide has been used.
Leonine facies from Actas Dermosifiliogr. 2013;104:285-98
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