Hello.  My husband had a very agressive chemotherapy with temodal, interferon alfa and radiation for treating  a reccurent malignant melanoma, stage III from november 2009 til november 2010.  Now, the results of RMN scan shows the presence of 2 aracnoid cysts of 2.6/3 cm and 2.8/2 cm.  The other results were perfectly normal.  He doesnt have any symptoms.Do you think it is possible that they appeared as a consequence of the chemotherapy?  Is it possible to disappear by themselves? What shall we do?  Please give us your opinion.Best regards.Dana Bozesan
Hi, Thanks for writing in. Arachnoid cysts in brain are benign thin walled cysts arising from the covering in the brain. It has nothing to do with aggressive chemotherapy for malignant melanoma. It does not cause any serious problem and in most cases is left untreated. Treatment involves complete cyst removal only when there is sufficient problem and symptoms that can be explained purely by the presence of the cysts. Most people have a single cyst and few have multiple cysts. Since he does not have symptoms, the arachnoid cysts are not a concern. However, a close follow-up must be done for malignant melanoma and should MRI be done at that time then a record of the increase in size of the arachnoid cyst might be made. These are slow growing and stable lesions. Please do not worry.