Answer: Vestigial tail, with tethering of cord and terminal lipomyelocele.
Findings:
A terminal vestigial tail which is predominantly composed of fatty tissues and few vascular channels seen protruding from sacral level. The base of the tail is surrounded by a ring of osseous elements. Spinal dysraphism seen at sacral level. Terminal lipoma seen extending through the dysraphic segments into the subarachnoid space with herniation of placode lipoma complex. The conus is low lying with posterior tethering of cord and terminal lipomyelocele. Linear syrinx seen at lumbar level extending from L1 to L5 level.
Discussion:
Two types of human tails have been recognized: the true and pseudo human tail. The true human tail arises from the most distal remnant of the embryonic tail lacking bone, cartilage, notochord and spinal cord. Contains a central core of mature fatty tissue divided into small lobules by thin fibrous septa with small blood vessels and nerve fibers scattered.
The true tail arises by retention of structures found normally in fetal development. It may be as long as 13 cm can move and contract, and occurs twice as often in males as in females. The pseudotail is a short, stump-like structure. Either can be associated with anomalies, such as myelomeningocele, meningocele, or lipoma.
A fetal tail is normally present from the fourth to eighth week of gestation. If it fails to regress, then a vestigial tail will remain. Human tails have been associated with multiple other anomalies in caudal regression syndrome, as part of a VATER sequence, and in Crouzon syndrome. Multiple studies show associated spinal dysraphism, of which a large proportion includes conditions such as meningocele, spina bifida occulta, tethered cord, and lipomyelomeningocele. Thus, presurgical MRI imaging, to look for neural elements is important in these cases.
Contributed By:
Dr. Karunakaran M. Kalathi MD, Dr. Arun Chelladurai MD
Consultant Radiologists, Aarthi Scans, Thirunelveli, Tamilnadu, India
Findings:
A terminal vestigial tail which is predominantly composed of fatty tissues and few vascular channels seen protruding from sacral level. The base of the tail is surrounded by a ring of osseous elements. Spinal dysraphism seen at sacral level. Terminal lipoma seen extending through the dysraphic segments into the subarachnoid space with herniation of placode lipoma complex. The conus is low lying with posterior tethering of cord and terminal lipomyelocele. Linear syrinx seen at lumbar level extending from L1 to L5 level.
Discussion:
Two types of human tails have been recognized: the true and pseudo human tail. The true human tail arises from the most distal remnant of the embryonic tail lacking bone, cartilage, notochord and spinal cord. Contains a central core of mature fatty tissue divided into small lobules by thin fibrous septa with small blood vessels and nerve fibers scattered.
The true tail arises by retention of structures found normally in fetal development. It may be as long as 13 cm can move and contract, and occurs twice as often in males as in females. The pseudotail is a short, stump-like structure. Either can be associated with anomalies, such as myelomeningocele, meningocele, or lipoma.
A fetal tail is normally present from the fourth to eighth week of gestation. If it fails to regress, then a vestigial tail will remain. Human tails have been associated with multiple other anomalies in caudal regression syndrome, as part of a VATER sequence, and in Crouzon syndrome. Multiple studies show associated spinal dysraphism, of which a large proportion includes conditions such as meningocele, spina bifida occulta, tethered cord, and lipomyelomeningocele. Thus, presurgical MRI imaging, to look for neural elements is important in these cases.
Contributed By:
Dr. Karunakaran M. Kalathi MD, Dr. Arun Chelladurai MD
Consultant Radiologists, Aarthi Scans, Thirunelveli, Tamilnadu, India