Mesenteric lymph nodes in children: what is normal?

BACKGROUND

Enlarged mesenteric lymph nodes (MLN) are frequently seen in children with abdominal pain and, in the absence of other disorders, have been attributed to primary mesenteric lymphadenitis.

OBJECTIVE

To evaluate the prevalence of enlarged MLN (short axis>or=5 mm) as detected by abdominal CT in children with a low likelihood for mesenteric lymphadenopathy.

MATERIALS AND

METHODS

During a 14-month period, we identified all non-contrast abdominal CT examinations performed at a tertiary care pediatric hospital for evaluation of suspected or known renal stones. Two radiologists reviewed the examinations and recognized all enlarged MLN, measured the short-axis diameter, and noted the quadrant location.

RESULTS

Sixty-one children were identified who met entry criteria; mean age was 10.7 years (range 1.1-17.3 years). Enlarged MLN were found in 33 (54%) of the 61 children; the largest enlarged MLN was most frequently in the right lower quadrant (RLQ) (29 of 33, 88%). Seventeen of the 61 children (28%) had three or more enlarged MLN; all were in the RLQ. The largest short-axis diameter measured was 10 mm.

SUMMARY: MLN with a short-axis diameter of >5-10 mm are commonly found on abdominal CT examination of children with a low likelihood for mesenteric lymphadenopathy and should be considered a non-specific finding. A short-axis diameter of 8 mm might better define the upper limit of normal mesenteric lymph node size in children.