A boy born to healthy, young, nonconsanguineous, white parents was born at 40 weeks of gestation by vaginal delivery after an uneventful pregnancy to a gravida I mother. The Apgar score was 9 and 10 at 1 and 5 min, respectively. Anthropometric parameters including birth weight (3480 g), length (52 cm), and head circumference (35.5 cm) were all normal (25th-50th centiles). On physical examination, the baby presented a constriction ring of the left arm, hypoplastic left upper limb (Fig. 1a), wrist, and fingers of the left hand in contracture (Fig. 1b), a skin-covered mass extending asymmetrically into the buttock, and a 7 cm caudal appendage of a soft, boneless, well-circumscribed tissue located at the sacrococcygeal region (Fig. 1c). Ultrasonography and MRI indicated a closed spinal dysraphism with nonossified posterior elements of superior sacral vertebrae and a lipomyelocele. The spinal cord was tethered at the level of L4-L5 tracted by the large lipoma, whereas fatty tissue was projecting out of the spinal canal inside the caudal appendage (Fig. 2). Liver microcalcifications and a bilateral grade I hydronephrosis were also observed on abdominal ultrasound. On ophthalmic examination, the retinal epithelium was hypopigmented, whereas the optic nerves and the fovea were intact. Heart anatomy and function were normal.The affected left upper limb was treated by multiple Z-plasty combined with removal of fibrous groove and fasciotomy. Neurosurgical excision of the caudal appendage was also performed. On last examination, at the age Fig. 1Left arm (a) and hand deformities (b) and the caudal appendage (c).