Skin-nontumor / Clinical dermatology
Other dermatoses
Radiation associated

Author: Mowafak Hamodat, M.D., MB.CH.B, MSc., FRCPC (see Authors page)

Revised: 20 July 2016, last major update August 2011

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: Radiation associated [title]

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’s sarcoma and well differentiated angiosarcoma (involves subcutaneous tissue, marked cytologic atypia, piling up of endothelial cells, Ki-67+)
  • 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 hyper pigmentation, telangiectasias and often alopecia

  • Description: Papules, small vesicles or erythematous plaques on irradiated field
Case Reports
Micro Description
  • Epidermis may be necrotic and accompanied by both spongiosis and intracellular edema
  • Hydropic degeneration of basal layer of epidermis and sometimes sub-epidermal 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’s 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