Malignant transformation of perianal tailgut cyst: A case report

Figure 1 Computed tomography and magnetic resonance imaging. A: A soft tissue mass and cystic density shadow were observed in the right hip and sacrococcygeal region (*), and the largest range was approximately 6.0 cm × 5.8 cm × 9.5 cm; B: The cyst was uneven, and the edge and septal of the focus were enhanced (↑); C and D: Multiple hypoechoic areas with a clear boundary (1.0–2.5 cm) were observed in the sacral region (∆) (C), and uneven echo areas in the right hip (▲) (D); E and F: The lesion had low-attenuation on T1 (*) (E) and high-attenuation on T2 (*) (F); G: Diffusion weighted image (↑). The longest diameter of the sagittal position was approximately 107 mm; H: The edge of the lesion was obviously enhanced (↑); I: Magnetic resonance imaging (T2) revealed a small cyst (▲) under the right levator ani.

Figure 2 Histopathological analysis. A: Moderate (▲)-to-severe (↑) dysplasia of the glandular epithelium; B: The columnar epithelial lining of the cyst wall had a large amount of mucus secretion, some of the epithelium had moderate dysplasia, and deranged smooth muscle bundles could be observed in the cyst wall (↑).

Figure 3 Macroscopic examination. A: A 13 cm × 12 cm lesion was found on the right hip, with obvious fluctuation, reddish skin on the surface, multiple ruptures, jelly-like fluid outflow, and cauliflower-like objects attached to the base; B: Gross examination of the specimen revealed brown and jelly-like fluid in the cyst; C: The orthopedists assisted with the free skin flap, and closed the incision.