For over eight years, a 37-year-old, Delhi-based woman silently battled a painful, discharging lesion on her lower back. The condition, located in the sacrococcygeal region near her tailbone, was repeatedly mistaken for a common infected sinus or abscess. Despite undergoing multiple incision and drainage (I&D) procedures, the lesion persisted—causing chronic pain, swelling, and periodic discharge.Strikingly, the patient exhibited no symptoms related to digestion or bowel movement, further complicating the clinical picture. The misdiagnoses and unsuccessful treatments continued for years, with little improvement in her quality of life. That was until a recent evaluation led to a breakthrough discovery.How Did The Diagnosis Happen?The patient’s condition took a dramatic turn when her case was referred to Redcliffe Labs, which is a pan-India diagnostic services provider. The consultant pathologist, Dr. Mayanka Seth, led the team that reviewed the case with a renewed perspective.Initial clinical assumptions continued to point toward common conditions such as pilonidal sinus or subcutaneous abscess. However, upon detailed examination, the team noted that the lesion was unusually deep and showed no communication with the anal canal. This prompted surgical intervention for complete removal of the cystic structure.Subsequent histopathological analysis confirmed a rare and unexpected diagnosis: subcutaneous tailgut cyst—a congenital lesion that arises from embryonic remnants of the hindgut. While tailgut cysts are rare in themselves, their typical location is deep within the pelvis. In this case, the cyst had developed just under the skin near the tailbone, making it an extremely rare presentation and a diagnostic challenge.The case also been documented and published in the Indian Journal of Case Reports. This has contributed to medical literature on rare congenital anomalies.Treatment and Complete RecoveryFollowing the complete surgical excision of the cyst, the patient experienced relief from her chronic symptoms. With no further discharge, pain, or swelling, her quality of life also improved.“This case throws light on the importance of considering rare congenital lesions when conventional treatments fail to provide results,” said Dr. Mayanka Seth. “Subcutaneous tailgut cysts are easily misdiagnosed due to their resemblance to more common infections in the sacrococcygeal area. Accurate diagnosis often hinges on thorough clinical evaluation and timely histopathological examination.”What Are Tailgut Cysts?As per Radippaedia, a peer-reviewed, open-edit radiology resource, Taligut cysts, also referred to as retrorectal cystic hamartomas are rare congenital growths believed to develop from remnants of the embryonic hindgut. These lesions are typically found in the retrorectal or presacral space, although extremely rare cases have been reported in unusual locations such as the perirenal region or subcutaneous tissues.Who Is Affected?Tailgut cysts show a strong female predominance and are most commonly diagnosed between the ages of 30 and 60. However, they can occur at any age.SymptomsIn many cases, tailgut cysts are discovered incidentally during imaging or unrelated examinations. When symptoms do occur, about half of the patients report perirectal discomfort, which may include pelvic pain or constipation.On gross examination, these cysts usually appear as multiloculated (multi-chambered), thin-walled masses with a shiny internal lining. They are typically filled with mucoid (gel-like) material. A distinguishing feature of tailgut cysts is their varied epithelial lining, which may include ciliated columnar cells, mucin-secreting columnar epithelium, transitional epithelium, and squamous cells.These lesions generally measure a few centimeters in size. Occasionally, they may be associated with defects in the sacral bone or exhibit internal calcifications.