History and admission findings: Six weeks before admission of a 47-year-old man with known rectal carcinoma, small nodular metastases had occurred over the front of both his thighs. Examination showed many aggregatet cuti-color or livid nodes, diameter 0.5 cm. The patient's poor general condition excluded the usual palliative measures.
Treatment and course: Photochemotherapy of the skin metastases with indocyanine green (ICG; absorption maximum 805 nm), a non-toxic dye approved for diagnostic purposes, was undertaken on a trial basis. The dye, being bound to plasma proteins, is retained in the intravacular space. Immediately after administration of the dye (2.5 mg/kg intravenously) the skin metastases were irradiated by diode laser (lambda = 805 nm, 100 J/cm2, 3 W/cm2, radiation diameter 2 cm). This necrosed the metastases and clinically as well as histologically resulted in their complete disappearance with scarring of the treated area.
Conclusion: This case illustrates the effectiveness of photochemotherapy with ICG against solid skin tumours of increased microvascular density.