[Small adenocarcinoma of the lung under long-term observation]

A 68-year-old man presented with symptoms of common cold at our hospital on March 8, 1995. Ground glass opacity (GGO) was detected in the right S 4 a by high resolution computed tomography (HRCT) during a routine examination. Except for mild traction of the nearest pleura, the lesion itself demonstrated little change on HRCT images for 2 years. HRCT images disclosed slight enlargement of the lesion over a long-term period of follow-up observation. Exactly 25 months after the first examination, HRCT scans demonstrated an area of centralized dense concentration. Right middle lobectomy was performed 30 months after the lesion was first detected. Pathologic findings from the resected specimen revealed Noguchi's small adenocarcinoma of the lung (type B classification: localized bronchioloalveolar carcinoma with collapse of alveolar structure). The lesion was scanned 8 times with HRCT during the follow-up period. The change to GGO with centralized density and spicula was observed in detail, and thought to be evidence of a progression from type A to type B. We concluded that a set of fixed settings should be utilized for repeated HRCT examinations of small peripheral lesions exhibiting GGO.