Alʹmanah Kliničeskoj Mediciny (Jun 2016)
PHOTODYNAMIC THERAPY OF TYPICAL AND ATYPICAL KERATOACANTHOMA
Abstract
Background: Photodynamic therapy (PDT) has shown its clinical efcacy in the treatment of keratoacanthoma. However, the published data is scarce and contradictory. Methods of a photosensitizer administration and irradiation doses depending on the type of keratoacanthoma have not been defned. Aim: To develop the diferentiated approached to PDT for typical and atypical keratoacanthoma by variation of the light density while using of a chlorine photosensitizer. Materials and methods: We assessed and treated 36 patients with cytologically and/or histologically confrmed solitary keratoacanthomas, among them 22 patients with typical and 14 patients with atypical ones. In 12 patients, persistent keratoacanthomas were diagnosed, in 1, a gigantic one and in 1, a centripetal one. Each patient was administered one session of PDT with an intralesional administration of a photosensitizer Radachlorin at a dose of 0.75 mL/cm3. The source of laser irradiation was a medical laser device LAMI (with the wave- length of 662 ± 3 nm, the power of irradiation at the edge of the light guide, 2 Wt). The absorbed light density was 50 J/cm2 for typical keratoacanthomas and 300 J/cm2 for atypical ones. 70 Results: After the treatment, in 32 (89%) of patients the tumor completely regressed within one month (26 ± 1.3 days). In 4 patients (all with atypical keratoacanthomas) the tumors did not regress within one month and was removed surgically with the 3 mm margins of obviously normal skin. At the site of former tumors, there were areas of atrophic scarring (26 cases, in 4 patients, with hyperpigmentation) or with normotrophic scarring (10 patients) that were cosmetically acceptable. Within the next 2 years of the follow-up no relapses were observed. Conclusion: Thus, we proposed an efective method of diferentiated approach to PDT of typical and atypical keratoacanthomas based on one PDT session with an intralesional administration of Radachlorin at a dose of 0.75 mg/cm3 of the tumor, with the intensity of irradiation of 0.39 Wt/cm2. The light dose density for typical keratoacanthomas is 50 J/cm2 and for atypical ones, 300 J/cm2.
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