Lipomatous lumbar mass with an attached digit and associated split cord malformation.

BACKGROUND

A male infant was born with a digit attached to a skin-covered lumbar lipomatous mass and an underlying split cord malformation.

METHODS

Surgical removal of the mass was performed at four months-of-age. By this time the digit had grown a nail and imaging and histology showed ongoing development of articulated phalanges.

RESULTS

The lipomatous mass contained a long bone, a clavicle- and scapula-like structure and a variety of other mature germ layer derivatives. These features raised a number of diagnostic considerations, including: mature teratoma, hamartoma, rudimentary parasitic twin, lipomyelomeningocele and dorsal accessory limb.

CONCLUSIONS

Based on review of the literature, the authors hypothesize that there is a pathogenetically related spectrum of skin-covered dorsal mass lesions, often associated with spinal dysraphism. These consist of a major lipomatous component and a variety of mature germ layer derivatives that can vary widely in their degree of anatomical organization from case to case.