Case 3

Carmen Timberlake, MD and Sven Laurin, MD

Clinical Presentation: A 13-month-old female with history of urinary tract infection presents for VCUG.  An incidental finding is noted.

Radiological Findings: Second non rib-bearing lumbar vertebral body with small right pedicle (white arrow).  No other osseous abnormality.

Figure 1

Discussion: Aplasia or hypoplasia of a lumbar pedicle is a rare congenital anomaly. Patients are typically asymptomatic.  In addition to the finding of unilateral small or absent pedicle, one may see enlargement of adjacent neural foramina and/or compensatory hypertrophy with sclerosis of the contralateral pedicle.  The latter finding is related to a stress response and is seldom evident in children.  Accordingly, the contralateral pedicle of our patient does not demonstrate this stress response.  The ipsilateral transverse process will always be in an abnormal position.

Differential Diagnosis:  Hypoplastic lumbar pedicle can be misinterpreted as a destructive bone lesion, which may lead to unnecessary work-up and anxiety.

References:

1. Carty H et al, eds.  Imaging Children, 2nd Edition. Elsevier, New York, 2005.
2. Kirks, DR, ed.  Practical Pediatric Imaging: Diagnostic Radiology of Infants and Children. Lippincott-Raven Publishers, Philadelphia, 1998.