Efficacy of OK-432 sclerotherapy in treatment of lymphatic malformations: long-term follow-up results.

Lymphatic malformations (LMs) are rare congenital tumors of the lymphatic system often affecting the head and neck area. Because of cosmetic and functional symptoms most patients need to be treated. Traditionally surgical treatment has been considered to be the first-line treatment for LM. However, it is challenging because of the need for complete excision. The risk of poor cosmetic result and damage to surrounding structures is high. Since Ogita presented OK-432 as a treatment for LM in 1987, it has been widely used as the primary treatment. Many papers have been published on this topic but with relatively short follow-up times. We present a material of 36 LMs treated with OK-432 during the period of 1999-2009 and with an average follow-up time of 6 years. Immediate post-treatment results were compared with the late follow-up findings. Primary and late response to therapy was evaluated with an MRI scan by measuring the change in lesion size. At the follow-up visit, all patients were clinically examined and they answered a symptom questionnaire. Later 26/36 patients were also available for a quality of life questionnaire. Primarily 67% demonstrated a complete or marked response. At the follow-up 64% showed a complete or marked response, in 11% the final response was better than the initially observed and only 2 patients had relapsed. The initial response predicted the long-term outcome accurately and the effect of OK-432 sclerotherapy seems to be long lasting. According to the MRI evaluation 80% and subjectively 94% of the patients benefitted from the treatment. Quality of life questionnaire showed high post-treatment satisfaction. We found OK-432 sclerotherapy to be a safe and effective treatment with a long lasting effect in the management of macrocystic LMs.