Visual Diagnosis: A 19-month-old Girl with a Lumbosacral Mass

Presentation

A previously healthy 19-month-old girl presents for evaluation of an enlarging mass over her lumbosacral region. The child and her family recently immigrated to the United States from Ethiopia, where the girl was born. The girl’s mother reports that the mass has been present since birth but was very small at that time. During the subsequent 19 months, the mass has continued to enlarge until it is easily noticeable under her clothing. The girl is reportedly developmentally normal and has no bowel or bladder dysfunction. Her mother is unsure whether the mass is painful because the girl does not cry when she lies on her back. The girl has had no fevers, no overlying redness of the skin covering or surrounding the mass, and no drainage from the mass. Due to inability to receive proper medical care in Ethiopia, she was brought to our emergency department for evaluation of the mass.

On physical examination the girl is thin, but well nourished. The mass is entirely covered by skin and sits midline over the lumbosacral region. It measures approximately 7×6×4 cm (Fig 1). The mass is mobile and fluid-filled, with only minimal tenderness to palpation. There is no overlying skin discoloration, and no abnormal cutaneous markings. The girl demonstrates the ability to walk normally, with appropriate lower-extremity muscle tone and intact lower-extremity sensation.

Initial ultrasonography performed in the emergency department reveals a large, irregular, cystic structure in the subcutaneous tissue with a tail extending deeper toward the spine. The girl is admitted to the hospital for further evaluation, and magnetic resonance imaging …