Abstract:

Cutaneous angiosarcoma (cAS) occurs on sun-exposed skin of the head and neck in older patients, as well as prior radiation sites and chronic lymphedema settings. Histopathologically, cAS can be challenging to detect in peripheral tumor areas that appear more differentiated, a difficulty which may be reflected in high recurrence rates. Among reported genetic aberrations in cAS, TP53 mutations have been described. We sought to determine the rate of aberrant diffuse strong immunohistochemical (IHC) expression of p53 in a series of cAS and the utility of p53 overexpression in assessing tissue involvement. Thirty-three tissue blocks (3 initial biopsies, 3 scouting biopsy series, and 3 excisions) from 7 patients were stained for p53. Of these 33 samples, by H&E, 9 showed definitive angiosarcoma, 7 were atypical but not diagnostic for angiosarcoma, and 17 were negative. Five of 9 samples with definitive angiosarcoma, 3 of 7 samples that were atypical but not diagnostic for angiosarcoma, and 5 of 17 samples that were negative on H&E showed distinct areas of aberrant p53 overexpression in endothelial cells lacking discernible pericytes on H&E. Immunohistochemistry for p53 increased the detection rate of cAS above the rate achieved with H&E by 24%. Further, 33% of negative or atypical samples (by H&E) showed endothelial cells with diffuse p53 overexpression. Whether p53 overexpression in endothelial cells without discernible pericytes represents true involvement by cAS or a field effect is unclear. Still, p53 overexpression has not been reported in normal skin. In our cohort, background skin, including vessels with discernible pericytes on H&E, showed no expression of p53. These data suggest that incorporation of p53 IHC as an adjunct in scouting biopsy assessment and/or in margin assessment on excisions for cAS has the potential to improve detection of abnormalities associated with angiosarcoma, which could guide surgical management and help reduce high recurrence rates.

Financial Disclosure:
No current or relevant financial relationships exist.

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Cooper Rutland, MD