Skin nontumor
Dermal collagen and elastic tissue alterations and metabolic disorders
Chronic radiation dermatitis
Last author update: 1 August 2011
Last staff update: 21 February 2024
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PubMed Search: Radiation associated [title]
Table of Contents
Clinical features | Case reports | Microscopic (histologic) description | Positive stains | Negative stains | Differential diagnosisCite this page: Hamodat M. Chronic radiation dermatitis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skinnontumorradiationassociated.html. Accessed January 5th, 2025.
Clinical features
- Radiation causes various benign vascular proliferations including benign lymphangiomatous papules (the lymphatic counterpart of telangiectases due to destruction/obstruction of lymphatic drainage), atypical vascular lesions mimicking benign lymphangioendothelioma, patch stage Kaposi sarcoma and well differentiated angiosarcoma (involves subcutaneous tissue, marked cytologic atypia, piling up of endothelial cells, Ki67+)
- Occurs 3 - 20 years after radiation exposure
- May be acute or chronic and follows therapeutic or accidental overexposure
- Often women treated for breast cancer
- Redness, swelling, hair loss and blistering
- Morbiliform, papular, annular and bullous lesions
- An erythema multiforme-like dermatosis is rare complication of radiotherapy
- Chronic radiation may present with acne vulgaris, ringworm, atrophy and scaling, variable hypo and hyperpigmentation, telangiectasias and often alopecia
- Description: papules, small vesicles or erythematous plaques on irradiated field
Case reports
- 49 year old woman with lesions secondary to breast cancer radiation (Am J Surg Pathol 2002;26:1372)
Microscopic (histologic) description
- Epidermis may be necrotic and accompanied by both spongiosis and intracellular edema
- Hydropic degeneration of basal layer of epidermis and sometimes subepidermal vesiculation
- Dermis is edematous and may show fibrin deposition; also dermal macrophages, eosinophils, plasma cells and lymphocytes
- In early stages, vascular thrombosis is a feature
- Chronic radiation dermatitis: epidermis shows hyperkeratosis and may show foci of parakeratosis, acanthosis or atrophy with attenuation of ridge pattern; may be spongiosis or basal cell liquefactive changes, cytologic atypia and dyskeratosis; dense fibrosis and elastosis in dermis, with fibrinous excaudate; blood vessels often thickened and fibrointimal hyperplasia is present; telangiectatic vessels may be present; loss of appendages, particularly hair follicles; associated with epidermal dysplasia, squamous or basal cell carcinoma
- Bizarre fibroblasts, with abundant polydendritic basophilic cytoplasm and large hyperchromatic or vesicular nuclei may suggest a neoplastic process; also seen in chronic lichen simplex, pressure ulcer and pleomorphic fibroma
- Post UV-B radiation: damaged keratinocytes (sunburn cells), intercellular edema and exocytosis; dermal changes include endothelial cell swelling and perivenular edema with a predominantly mononuclear intradermal chronic inflammatory cell infiltrate; also elastosis in fair skinned individuals
- Post UV-A radiation: keratinocyte swelling, vacuolation accompanied by intercellular edema and diminished numbers of Langerhans cells, but no sunburn cells; dermis has mixed infiltrate of neutrophils, lymphocytes and occasionally basophils and eosinophils; also endothelial swelling
- Benign lymphangiomatous papules/plaques: superficial dermal involvement by irregularly dilated vascular spaces in branching and anastomosing pattern; vessels have thin walls and lymphatic appearance, with single layer of discontinuous flattened endothelial cells; also numerous small stromal papillary formations lined by endothelial cells that project into lumina
- Atypical vascular proliferations mimicking benign lymphangioma or patch stage Kaposi sarcoma: poorly circumscribed and focally infiltrating, irregular jagged vascular spaces involving entire dermis; lined by inconspicuous endothelial cells; variable dissection of dermal collagen bundles
Positive stains
- CD31 stains vessels
Negative stains
Differential diagnosis
- Acute GVHD
