Computed tomography in 101 patients with a palpable abdominal mass.

A total of 101 patients with a palpable or suspected abdominal mass of unknown origin were examined by computed tomography (CT). In 69 patients an abnormality was demonstrated at the site of the palpable mass; only in one patient was this finding erroneous (false positive). In 32 patients no lesion was demonstrated (one false negative). Such high positive and negative predictive values (99% and 97%) indicate the value of CT in determining the presence or absence of a lesion to account for a clinically apparent mass, especially when there is doubt as to its presence or organ of origin. As to the cause of the mass, CT correctly identified the responsible organ or structure in 64 out of 69 patients with a lesion (93%) and suggested the likely nature in 61 (88%).