The "cluster of black pearls" sign of sarcoid lymphadenopathy: a new sign on thin-section contrast-enhanced multidetector CT.

AIM: To identify a specific diagnostic sign for sarcoid adenopathy on contrast-enhanced multidetector computed tomography (MDCT) based on nodal morphology.

MATERIALS AND

METHODS

A prospective study was performed on 105 patients with 1654 nodes. Of this, 18 patients with sarcoidosis formed the study group. The control group consisted of the remaining 87 patients with other proven disease entities of metastatic adenocarcinoma, lymphoma, tuberculosis, and reactive adenopathy for comparison. CT examinations were undertaken using a 64-section helical mode in the arterial and venous phases with a 0.5-mm section thickness. The lymph nodes were evaluated for various morphological criteria and the presence of the "cluster of black pearls" (CBP) sign. The CBP sign was considered present when tiny round nodules each measuring 1-2 mm were seen distributed uniformly within the whole or part of the lymph node.

RESULTS

The CBP sign had a significance of p<0.001, 83% sensitivity, 98% specificity, 91% positive predictive value, and 96% negative predictive value on a per node basis and a sensitivity of 100% on a per patient basis.

CONCLUSION

The CBP sign is an accurate morphological sign differentiating sarcoid from other adenopathy.