A Tarlov cyst at S2 should not cause leg pain as the S2 nerve radiates to the perineal region (coccyx region) and does not radiate down the leg. I would make sure the symptoms are originating from the Tarlov cyst before further discussions are made. Local Tarlov cyst pain can occur by bone erosion but there has to be significant erosion as I’ve seen 50% of the sacrum eroded without symptoms.
Donald Corenman, MD, DC is a highly-regarded spine surgeon, considered an expert in the area of neck and back pain. Trained as both a Medical Doctor and Doctor of Chiropractic, Dr. Corenman earned academic appointments as Clinical Assistant Professor and Assistant Professor of Orthopaedic Surgery at the University of Colorado Health Sciences Center, and his research on spine surgery and rehabilitation has resulted in the publication of multiple peer-reviewed articles and two books.