Assessment of 5-aminolevulinic acid-induced porphyrin fluorescence in patients with peritoneal endometriosis

OBJECTIVE: The purpose of this study was to examine the diagnostic potential for patients with endometriosis of porphyrin fluorescence after oral administration of 5-aminolevulinic acid. STUDY DESIGN: Fifteen women referred for laparoscopy because of suspected endometriosis received 1 or 10 mg/kg 5-aminolevulinic acid orally. After 1.5 to 6 hours endoscopic fluorescence spectral analysis and video inspection were performed. RESULTS: With 10 mg/kg 5-aminolevulinic acid and application intervals of >3 hours we observed a significantly higher porphyrin fluorescence in active peritoneal endometriosis than in adjacent normal peritoneum. Pigmented and nodular endometriosis showed weak to negative fluorescence. A strong fluorescence of the fimbrial mucosa was seen. A 1-mg/kg dose of 5-aminolevulinic acid was insufficient for fluorescence diagnosis. No side effects were recorded. CONCLUSION: Porphyrin fluorescence after oral administration of 5-aminolevulinic acid may be beneficial in diagnosis of peritoneal endometriosis. The strong fluorescence of fimbrial mucosa may limit the applicability of this technique in young women, however, because phototoxic damage cannot be excluded at present.