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

ABSTRACT

BACKGROUND: The enlarged mediastinal lymph nodes caused by tuberculosis (TB) and chronic lymphocytic leukaemia (CLL) are similar, sometimes resulting in misdiagnosis of the two diseases. OBJECTIVE: To determine the differential characteristics of enlarged mediastinal lymph nodes caused by TB and CLL using multidetector-row computed tomography (MDCT). MATERIALS AND METHODS: 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%). RESULTS: 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). CONCLUSION: The distribution and enhancement pattern of enlarged lymph nodes on MDCT was useful in differentiating TB and CLL.