Koebner Phenomenon in Kaposi's Sarcoma: A Large Single-Center Case Series and Review of Current Knowledge.

Background: occasional case reports have described the appearance of Kaposi's sarcoma (KS) on previously unaffected skin after incidental or accidental injury, but the association is probably under-reported.

Objectives: to present a large case series of patients suffering from Koebner phenomenon (KP) in KS and describe their main epidemiological, clinical, and therapeutic features.

Methods: we have retrospectively analyzed our clinical and photographic records of 524 patients who had been diagnosed with KS between 2009 and 2021.

Results: 31 of 524 (6%) KS patients developed KP. Among these 31 patients, 24 (77%) had KS lesions after surgery, 4 (13%) after electrochemotherapy, laser therapy and cryotherapy, and 3 (10%) on areas affected by bullous diseases.

Conclusions: trauma, including surgery or other medical procedures, can trigger KS, underlying the importance of treatment options which cause the least injury to the skin.