Ischiopubic synchondrosis asymmetry

Ischiopubic synchondrosis asymmetry (also known as van Neck-Odelberg disease) is characteristic enlargement of one of the ischiopubic synchondroses. It is largely considered an anatomic variant of skeletal developmental, given that it is a common and usually asymptomatic finding.

However, some cases are thought to be symptomatic and may correspond to MR findings that suggest a stress reaction 7,8.

Occurs in all children before puberty during fusion of the pubic and ischial bones 3.

Most cases of ischiopubic synchondrosis asymmetry are observed in asymptomatic patients. Symptomatic cases are described as presenting with groin or buttock pain in ambulatory, pre-pubertal children 7,8

Ischiopubic synchondrosis asymmetry is much more common on the side of the weight-bearing non-dominant foot, with the differences in ossification thought to result from asymmetric mechanical forces 3

Recognition of an entity as a normal variant is important for radiologists when interpreting a pediatric pelvic radiograph. One of the key questions to ascertain is whether the region is painful or not:

  • if asymptomatic and there is no concerning antecedent history: it is unlikely to represent a sinister pathology other than just a developmental variant
  • if symptomatic or if the there is concerning antecedent history: it could still be a developmental variant although other important differential considerations should also be considered

Ischiopubic synchondrosis can be avid on bone scintigraphy 10 and FDG PET/CT.  

On imaging alone, the condition can mimic many other pathological entities including:

The preceding clinical history is crucial in image interpretation.

The condition is named after M van Neck and A Odelberg who initially described these findings in 1924 4,5.

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Article information

rID: 21626
Section: Syndromes
Synonyms or Alternate Spellings:
  • Asymmetric ischiopubic synchondrosis
  • Van Neck disease
  • Ischiopubic synchrondrosis syndrome
  • van Neck-Odelberg disease
  • Osteochondrosis ischiopubica
  • Enlarged ischiopubic synchondrosis
  • Hyperostosis of the ischiopubic synchondrosis
  • Ischiopubic synchondrosis syndrome

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Cases and figures

  • Case 1
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  • Case 2
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  • Case 3: symptomatic
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  • Case 4: x-ray, annotated
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  • Case 5
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