External validation of prediction scores of positive random skin biopsy in suspected intravascular large B-cell lymphoma.

Fourteen patients (16%) had a positive random skin biopsy.

Marianna score had the best 3-risk-group model performance, both the Okayama and St.

The Kameda score rarely stratified patients as high risk, resulting in limited predictive performance.

In settings where missed diagnoses are considered more harmful than unnecessary biopsies, the 2-risk-group classification and the 3-risk-group model of each score performed similarly.