原発性肺癌術後の孤立性病変切除例の診断

Surgical Cases of Solitary Lesion after Surgery for Primary Lung Cancer

異時性肺癌に対する外科治療の良好な成績から，耐術可能であれば外科治療が推奨されており1），また，肺癌再発に対する再生検を目的とした肺切除も積極的に施行されている．一方，このような症例で肺切除の結果，非悪性疾患と診断されることもしばしばである．われわれは，原発性肺癌術後の新規孤立病変に対して肺切除を行い，非悪性疾患であった症例について，文献的考察を加えて報告する．

Lung nodules during postoperative follow-up of lung cancer are generally suspected to be its recurrence, but some cases are diagnosed as non-malignant disease. From January 2001 to November 2018, we experienced 5 （4.5％） new non-malignant lesions in 112 lung cancer patients who underwent a lung resection. The average period from first to second lung surgery was 36.2 months （range：3-64）, and computed tomography findings before the second surgery were solid nodules in four cases and ground-glass opacity in one case. The average maximum standardized uptake value of the lesions on fluorodeoxyglucose positron emission tomography was 4.29 （range：0-10.85）. The diagnosis after the second surgery was pulmonary cryptococcosis in 2 cases, nontuberculous mycobacteriosis in 1 case, inflammatory mass in 1 case, and pneumonia in 1 case. The differential diagnosis between these diseases and lung cancer recurrence is discussed in the present study.