Sclerotherapy remains the standard for interventional treatment of slow-flow vascular malformations. However, bleomycin electrosclerotherapy (BEST) has shown promising results in the management of recurrent lesions. One notable adverse effect of BEST is the postinterventional development of skin hyperpigmentation. The aim of this study is the analysis of accidental skin hyperpigmentation after BEST of slow-flow vascular malformations.This retrospective study at our interdisciplinary vascular anomalies center investigated the occurrence of skin hyperpigmentation after bleomycin electrosclerotherapy of slow-flow vascular malformations over a period of 21 months documented clinically and in photographic findings, as well as related interventional treatment parameters with subsequent exploratory threshold analyses at 0.10 and 0.15 mg/kg. Subsequently, a comparison was made with recent publications reporting hyperpigmentation after bleomycin administration.During the observation period, 72 patients were included with a total of 80 BEST procedures. Bleomycin-related skin hyperpigmentation was documented in 4 of 7 lymphatic malformation (LMs), 20 of 44 venous malformation (VM)and in 16 of 29 combined venolymphatic vascular malformations associated with other anomalies. On average, 27.1 application series of reversible electroporation per intervention were performed (range 1-85).An average of 8.37 mg bleomycin was administered to LMs, 5.31 mg to VMs and 8.03 mg to the combined group in each session. Hyperpigmentation was more frequent with the hexagonal electrode: 33/56 (58,9 %); Needle-Foil Electrode (NFD) 6/19, Variable Geometry Device (VGD) 1/5. Rates were similar across entities (hexagonal: LM 3/5, VM 17/31, combined 13/20). Overall, bleomycin was administered intralesional 46 times with an average dose of 0.09 mg/kg bw (range 0.008-0.23) and intravenously 34 times, 0.22 mg/kg bw (range 0.13-0.5). Hyperpigmentation was more frequent after intravenous administration (61.8 %) than intralesional (41.3 %), likely reflecting higher dosing. A threshold dose of ≥0.10 mg/kg bleomycin was associated with a higher risk ratio for hyperpigmentation (RR 2.30, 95% CI 1.27-4.15).The frequency of skin hyperpigmentation following BEST seems to be analog to bleomycin-induced flagellate dermatitis and appears more frequently when using the hexagonal electrode and a higher bleomycin dosage per kg bodyweight (bw). · Puncture related skin hyperpigmentation is a frequent but often underestimated adverse effect of Bleomycin electrosclerotherapy (BEST) in slow-flow vascular malformations.. · Our findings suggest that electrode geometry and puncture-related trauma contribute substantially to this side effect.. · Recognizing these factors allows for more informed electrode selection and patient counseling to minimize the risk and improve cosmetic outcomes after BEST.. · Exploratory analyses suggest higher mg/kg dosing increases hyperpigmentation risk. When clinically feasible, consider dose minimization especially in cosmetically sensitive areas.. · Loeser JH, Schramm D, Cucuruz BR etal. Bleomycin Electrosclerotherapy and Skin Hyperpigmentation in Slow-flow Vascular Malformations: A Retrospective Monocentric Analysis. Rofo 2026; DOI 10.1055/a-2783-4420.
Loeser et al. (2026) studied this question.