INTRATHORACIC LYMPHADENOPATHY IN PATIENTS WITH EMPYEMA

Purpose: Our goal was to determine the prevalence of intrathoracic lym phadenopathy on chest CT in patients with empyema. Method: We retrospe ctively identified 27 patients (14 men, 13 women, mean age 43 years) w ith nontuberculous empyema examined with chest CT. All scans were revi ewed by two of three board-certified radiologists for the presence of intrathoracic lymphadenopathy (greater than or equal to 1 cm, short ax is) in an American Thoracic Society (ATS) nodal station or the interna l mammary region. Differences were resolved by consensus. Results: Thi rteen (48%) patients with empyema had lymphadenopathy on chest CT. The mean number of enlarged lymph nodes for the patients with lymphadenop athy was 3.2 (SD+/-2.3, range 1-8). The mean size of the largest lymph node was 1.4 cm (range 1.0-2.5 cm). The lymphadenopathy was unilatera l and ipsilateral to the empyema in seven (54%), bilateral in five (38 %), and unilateral contralateral to the empyema in one. The distributi on of lymphadenopathy according to ATS nodal stations was 4R (n = 8), 7 (n = 6), 10R (n = 5); n = 2 each 2R, 10L, 11L; and n = 1 each 11R, 2 L, 4L, and 6. Four patients had internal mammary lymphadenopathy. Pleu ral fluid and smooth pleural thickening were present in each case. Fou r patients had follow-up CT after treatment. There was a decrease or r esolution of the lymphadenopathy in each case. Conclusion: Intrathorac ic lymphadenopathy is a common CT finding in patients with empyema and occurred in 48% of this series. In patients with smooth pleural thick ening and pleural effusion, intrathoracic lymphadenopathy should not b e used as a criterion to differentiate empyema from malignant or tuber culous pleural effusion.