The results of the study sample (69 patients) was divided into group I (48 patients) including patients who presented mainly with pleural effusion and group II (21 patients) including patients who presented with peripheral pulmonary lesions.
Group I (pleural effusion group)
Forty-eight patients were enrolled within the pleural lesion group (20 males “41.7%” and 28 females “58.3%”). Patients’ ages ranged from 15 to 73 years (mean age = 50.3 ± 15.5).
Histopathological/cytological evaluation of the patients in the pleural effusion group showed that 16 cases were malignant (10 males “62.5%” and 6 females “37.5%”) and 32 were non-malignant (10 males “31.3%” and 22 females “68.8%”). Within the benign cases, 24 cases revealed exudate and 8 cases revealed transudate.
According to the volume, 4 cases (8.3%) had a minimal amount of pleural effusion, 16 cases (33.3%) had a small amount, and 12 cases (25.0%) had a moderate amount, while 16 cases (33.3%) had massive amount. According to echogenicity, 18 cases (37.5%) were clear anechoic and 18 cases (37.5%) were complex nonseptated while 12 cases (25.0%) were complex and septated. Also, US showed encysted effusion in 12 cases (25.0%), pleural thickening in 18 cases (37.5%), and underlying pulmonary consolidation/collapse in 4 cases (8.3%).
On the correlation of the ultrasound findings with the cyto-histological results, we found that:
According to the effusion volume, 8 (50%) of the malignant effusions were massive effusions, while only 4 cases (25%) were small, 2 cases (12.5%) were minimal, and 2 were moderate. For the benign effusions, 12 cases (37.5%) were small, 10 (31.3%) were moderate, 8 (25%) were massive, and 2 (6.3%) were minimal. No significant statistical difference was found between the benign and malignant lesions regarding the pleural effusion volume (P value = 0.212).
The presence of septations within the pleural fluid also showed no significant difference between the benign and the malignant cases (P value= 0.287) and between the inflammatory (transudate) and noninflammatory (exudate and malignant effusions) pleural effusions (P value = 1).
Encysted pleural effusion was found in 6 malignant cases (37.5%) and in the same number of the benign cases (18.8%) with no significant statistical difference noted (P value = 0.157).
Eighteen cases of the pleural effusion group showed associated pleural thickness, 8 of them were malignant and 10 were benign with no significant statistical difference in its incidence between benign and malignant lesions (P value = 0.206). Thirteen malignant cases showed pleural nodularity in contrast to only one benign case nodularity. A significant difference was found between malignant and benign lesions regarding the presence of pleural nodularity (P value < 0.001).
Significant statistical difference was found between the benign and malignant effusions regarding the measurement of the associated costal pleural thickening (P value = 0.021). Receiver operating characteristic (ROC) curve (Fig. 5) analysis was performed for the values of the pleural thickening in the benign and malignant groups. It defined cutoff value of 0.75 cm at a maximum combined sensitivity and specificity of 75% and 80% respectively and area under the curve of 0.825.
Group II (peripheral pulmonary lesion group)
Twenty-one patients were enrolled within the peripheral pulmonary lesion group (18 males (85.7 %) and 3 females (14.3%)). Patients’ ages ranged from 20 to 80 years (mean age = 57.3 ± 13.7).
In the histopathological evaluation of the pulmonary lesions, 15 cases were malignant (14 males “93.3%” and only 1 female “6.7%”) and 6 were benign (4 males “66.7%” and 2 females “33.3%”).
According to the mass border, 15 cases (71.4%) had well-defined border and 6 (28.6%) showed ill-defined one. According to echogenicity, 9 cases (42.9%) were isoechoic and 8 (38.1%) were hypoechoic while 4 (19.0%) appeared hyperechoic. According to echopattern, 12 cases (57.1%) were homogenous and 9 (42.9%) were heterogeneous. According to the pattern of vascularity, 16 cases (76.2%) showed disturbed pattern and 5 cases (23.8%) were of normal pulmonary vascular pattern. Also, US showed intrinsic air bronchogram in 8 cases (38.1%) and extension to the pleura in 13 cases (61.9%) while chest wall invasion was seen in 7 cases (33.3%).
On correlating the US findings with the cysto-histological results, we found that:
According to the border definition, within the 15 malignant cases, 10 cases (66.7%) had a well-defined border and 5 (33.3%) had an ill-defined one. In the benign lesions, 5 cases (83.3%) had a well-defined border and only 1 case (16.7%) showed an ill-defined border. No significant statistical difference was found between the benign and malignant lesions regarding the mass border (P value = 0.623).
According to the lesion echogenicity, 8 (53.3%) of the malignant lesions were isoechoic, while 4 (26.7%) were hypoechoic and 3 (20.0%) were hyperechoic. For the benign lesions, 4 (66.7%) were hypoechoic while only 1 case (16.7%) was isoechoic and the other one (16.7%) was hyperechoic. No significant statistical difference was found between the benign and malignant lesions regarding the pulmonary mass echogenicity (P value = 0.211).
According to the lesion echopattern, 8 malignant cases (53.3%) and 4 benign cases (66.7%) were homogenous, while 7 malignant cases (46.7%) and only 2 benign cases (33.3%) were heterogeneous. No significant statistical difference was found between the benign and malignant lesions regarding lesion echopattern (P value = 0.659).
According to the intralesional air bronchogram, 3 (20%) of 15 malignant lesions while 5 (83.3%) of 6 benign lesions showed intrinsic air bronchogram. A significant difference was found between the benign and malignant lesions regarding the intralesional air bronchogram (P value = 0.014).
Intralesional disrupted vascularity pattern was found in all the malignant lesions (100%), while only it was found in one benign case (16.7%). It showed a significant difference between malignant and benign lesions (P value ≤ 0.001).
Seven (46.7%) of the malignant lesions showed an extension to the pleura or the chest wall while none of the benign lesions showed evidence to the pleural or chest wall invasion. There was a significant difference between malignant and benign lesions regarding the pleural (P value = 0.016) and chest wall (P value = 0.004) invasion respectively.