<s>[INST] In march 2012 I was diagnosed w/a 1 cm lung nodule. Following a second PET scan I was told that I had lesions in my spleen. I had an ultrasound that confirmed a benign cyst. I am going to the lung nodule program in Fresno on the 30th. However, I am now concerned about this cyst in my spleen. Can it be dangerous? [/INST] Thanks for your question on Chat Doctor. I can understand your concern. No need to worry much for the benign cyst in spleen. But follow up with ultrasound every six monthly fir 1st year is required to confirm the benign nature of lesion. If size and appearance of cyst remain same then it is a benign cyst. But if size increases or cyst becomes more heterogeneous than you need biopsy from the lesion to rule out malignancy. Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks. </s>