ackground : Because there are many different reporting results about the etiologies of
solitary pulmonary nodules (SPNs), we cannot know the exact incidence of each causative
disease. SPNs have a good prognosis relatively even if it is a malignant lesion. In
Korea, where there is a high incidence of pulmonary tuberculosis, the differential diagnosis
of SPNs should be performed.
Methods : Among 351 patients who visited Wonju Chistian Hospital for SPNs in chest
x-ray between 1982 and 1989, we evaluated 74 patients in whom the causes of SPNs
could be elucidated by sputum AFB study, cytology, histolgic study, chest of solitary
pulmonary nodule (SPN) seen at the Wonju Christian Hospital from 1982 to 1989.
The followings were obtained.
1) The malignancies of SPN 74 cases were 25 cases (33.7%). The primary lung
carcinomas were 24 cases : the epidermoid carcinomas of these were 11 cases (45.8%),
metastasis 1 case, tuberculoma 42 cases, and the other 7 cases.
2) The age distribution of bengin lesions was from 19 to 73 years old with the mean
age of 46 years old, and the age distribution of malignancies was from 17 to 77 years old
with the mean age of 57 years old. The 23 cases (92.0%) of malignant nodules were more
than 40 years old. The malignant frequency of SPN in a group of age more than 40 years
old was 40.3% and in a group of age less than 40 years old, it was 11.7%. The
malignant frequency was directly preportional to the increase of age (p<0.05).
3) The 3 cases of SPN were detected accidentally during physical check up, all
were benign. The 14 cases were detected during the evaluation of other diseases, 12 cases
were bengin. The 23 cases (40%) of 57 cases were symptomatic. Chest pain, dyspnea, and
weight loss frequency in a group of less than 3 cm in size was 11.9% and in a group
of more than 3 cm in size, it was 62.5% (p<0.05).
4) Calcifications were noted in 15cases of 74 cases on the plain films, all were 7
central types, 7 diffuse types and 1 popcorn type. One of malignant cases had calcification
on the chest CT scar.. Among the 59 cases with non-calcified nodules, 25 cases were
malignant (42.3%). The mean Hounsfield Unit of benign lesions was 182.5U and that of
malignancies was 94U, there was a statistical difference between both groups(p<0.01).
5) The 21 cases (50%) of tuberculomas were located at the apicoposterior segment of
upper lobe or the superior segment of lower lobe, but the 7 cases (28%) of malignancies
were located at above sites.
6) The diagnostic accuracy of sputum study was 9.4% and that of fiberoptic
bronchoscopy (FOB) was 33.3%. The diagnostic accuracy of transbronchial lung biopsy
(TBLB) and transthoracic needle aspiration biopsy (TTNAB) was 57.4%. The percentage
of primary lung cancer among SPNs which are larger than 3 cm in size, occurring in the age
of older than 40 years old and with no calcifications on radiologic examintion should be
suspected as malignancies and diagnosed with sputum study, fiberoptic bronchoscopy, TBLB,
and TTNAB.
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