Growth pattern change of a benign clear cell 'sugar' tumor of the lung: Serial imaging surveillance over seven years.

Clear cell tumor of the lung is a rare benign mesenchymal tumor and only sporadic cases have been previously reported. The present study reports the case of a 58-year-old man who presented with an incidentally detected solitary pulmonary nodule. Based on comparisons with serial previous chest and spine radiographs, a growth pattern change in the nodule (initial gradual growth over 4.5 years, then recent no growth over 2.5 years) was identified. The nodule was diagnosed as a benign clear cell tumor of the lung (CCTL) following surgical resection. Few studies have previously reported interval growth of CCTLs and the growth pattern of CCTL is not yet well known. To the best of our knowledge, this is the first reported case in which the growth pattern change of CCTL was identified via serial imaging over 7 years of follow-up.