Tuberculosis vs. chronic lymphocytic leukaemia in mediastinal lymph nodes using computed tomography

The enlarged mediastinal lymph nodes caused by tuberculosis (TB) and chronic lymphocytic leukaemia (CLL) are similar, sometimes resulting in misdiagnosis of the two diseases.

To determine the differential characteristics of enlarged mediastinal lymph nodes caused by TB and CLL using multidetector-row computed tomography (MDCT).

We conducted a retrospective analysis for the anatomical distribution and enhancement patterns of mediastinal lymph nodes on MDCT in 67 consecutive patients with newly diagnosed untreated TB (58%) and CLL (42%).

Concerning the main anatomic distribution of lymph nodes, TB involved the 4R (n = 32, 82%) and 10R (n = 27, 69%) regions more often than CLL (n = 16, 57%; n = 12, 43%, respectively). Contrast region 1 had a greater tendency to be affected in CLL (n = 16, 57%) than TB (n = 11, 28%). TB showed peripheral enhancement in 28 cases (72%), frequently with a multilocular appearance, compared to CLL, which showed no peripheral enhancement in these cases. Homogeneous enhancement was more commonly seen in CLL than in TB (82% vs. 10%, P < 0.01).

The distribution and enhancement pattern of enlarged lymph nodes on MDCT was useful in differentiating TB and CLL.