Clinical Challenge: Plaque on the Back After a Heart Attack

Chronic radiation dermatitis may occur in patients with a history of exposure to ionizing radiation. The skin findings are not evident at the time of radiation therapy but clinically appear following a latent period that can range from months to...

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Chronic radiation dermatitis may occur in patients with a history of exposure to ionizing radiation. The skin findings are not evident at the time of radiation therapy but clinically appear following a latent period that can range from months to years.

Skin lesions commonly present with hypopigmentation, atrophy and telangiectasias. The degree of damage to the skin, hair and nails is variable.

In this case, the radiation exposure was to fluoroscopy that interventional cardiologists use during stent placement. This is a relatively rare complication of fluoroscopy. The shape of the plaque of radiation dermatitis corresponds to the area of maximum irradiation during the procedure.

Chronic exposure to ionizing radiation can also lead to the development of both basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs). These neoplasms usually occur following a longer latent period of about 20 to 40 years.  

In contrast to sun-induced SCCs, SCCs resulting from radiation therapy are more likely to metastasize. Angiosarcomas, sarcomas, malignant fibrous histiocytomas and thyroid carcinomas are other malignancies that can develop following radiation therapy.

Diagnosis

The diagnosis is based on physical exam findings in conjunction with a history of prolonged exposure to ionizing radiation. Overall, the skin can become dry, shiny and thin, with an increased tendency to ulcerate.

Some areas of skin can become atrophic and hypopigmented with freckling; telangiectasias can also be evident. Both hair and nails can become brittle. Tender, erythematous plaques may also develop as a result of subcutaneous fibrosis and binding of deep and superficial tissue layers.

The extent of the dermatitis depends on the extent of radiation exposure.  In the case presented above, only a small skin area was exposed to significant radiation and hence the radiation dermatitis is quite limited. 

In contrast to chronic radiation dermatitis, acute radiation dermatitis occurs within 24 hours following exposure to higher doses of ionizing radiation. The skin becomes erythematous with a second phase of erythema that usually occurs three to six days after treatment. 

Other skin findings can include edema, ulceration and vesiculation. Desquamation can also occur. Morphea is defined as localized scleroderma confined to the skin. Lesions appear as indurated, sharply demarcated plaques that are distributed in a linear, patchy or asymmetric distribution.

Early inflammatory lesions can have a lilac border with a white center, whereas more mature lesions exhibit hyperpigmentation.

Lastly, nephrogenic systemic fibrosis is a scleroderma-like disorder that not only affects the skin, but also the internal organs. Renal insufficiency in conjunction with gadolinium-based contrast agents is known to lead to this disorder.

Skin lesions appear clinically as thick, indurated plaques that can either be erythematous or hyperpigmented and are distributed symmetrically on the extremities and trunk.

Treatment    

Chronic radiation dermatitis requires minimal care. Patients should cleanse with mild soap and water and use emollients. The area should be monitored for malignancy, which may develop after 20 to 40 years.

Shelly Gurwara, BS, is a senior medical student at Louisiana State University Health Sciences Center in Shreveport.  

Adam Rees, MD, is a graduate of the University of California Los Angeles School of Medicine and a resident in the Department of Dermatology at Baylor College of Medicine also in Houston.