Japanese to English Science Medical (general)

集積 vs 斑(状影)
I see both of these terms translated as mass on the web. Is “mass” correct for both terms?
PET/CT検査異常所見：要請査.
上腰部正中やや右側で、腹腔内の腹壁に接して約１ｃｍ大の集積がみられました。
Abnormal PET/CT examination findings: Detailed examination necessary
We observed a large mass of about 1 cm connected to the wall of the abdominal cavity and slightly to the right of the center of the upper lumbar region.
胸部ＣＴ所見: 左肺舌区に淡い斑状影を認め右肺下葉に小結節影認めます。また右肺底部に索状影を認めます。
Chest CT findings: A faint shadow of a mass was detected in the lingua of the left lung and a shadow of a small nodule was detected in the right lower lobe of the lung.