Discrimination of well-differentiated liposarcoma from benign lipoma on sonography: an uncontrolled retrospective study

PURPOSE

Well-differentiated liposarcoma, the most common subtype of liposarcoma, should be discriminated from benign lipoma. However, features on sonography for discriminating these two types of tumor have not been fully investigated. The present study was therefore aimed at clarifying differences in sonographic findings between well-differentiated liposarcoma and lipoma.

METHODS

The study population comprised 23 cases of well-differentiated liposarcoma and 181 cases of lipoma. We investigated differences in sonographic appearance and pathological findings between the two types of tumor.

RESULTS

Well-differentiated liposarcoma tended to develop more frequently in older patients and in the lower extremities including the gluteal region, compared with lipoma. Concerning sonographic findings, both tumors exhibited well-defined margins and heterogeneous internal echogenicity, including typical tiny striated hyperechoic lines. Well-differentiated liposarcoma was characterized by a higher frequency of the following findings compared with lipoma: (1) deep location, (2) irregular shape, (3) large diameter, (4) hyperechogenicity compared to surrounding tissue, and (5) presence of vascularity on Doppler sonography (p < 0.01 each). Notably, hyperechogenicity corresponded to the intermingled sclerosing component within the adipocytic component when sonographic findings were compared with those of pathology.

CONCLUSION

The present study suggests that several sonographic findings including hyperechogenicity and presence of vascularity might be key features for discriminating well-differentiated liposarcoma from lipoma.

Sonographic Appearances of Liposarcoma: Correlations with Pathologic Subtypes

Liposarcoma is the second most common malignant soft-tissue tumor. This entity is pathologically categorized into 4 subtypes: well-differentiated, myxoid, dedifferentiated and pleomorphic. Although features on magnetic resonance imaging and computed tomography for these 4 subtypes have been reported quite precisely, those on sonography have not been fully investigated. The present study was therefore aimed at clarifying the sonographic appearances of each liposarcoma subtype and assessing correlations with histopathology. The study population was made up of 35 cases, including 21 cases of well-differentiated liposarcoma, 6 cases of myxoid liposarcoma, 6 cases of dedifferentiated liposarcoma and 2 cases of pleomorphic liposarcoma. Compared with the other subtypes, well-differentiated liposarcoma was characterized by the high frequency of the following findings: isoechogenicity, tiny hyperechoic lines and hypovascularity (p < 0.01, in each). Myxoid liposarcomas were characterized by low echogenicity, intermingled with anechoic areas and moderate vascularity (p < 0.01, in each). Dedifferentiated liposarcomas showed a specific biphasic pattern of hyperechoic and hypoechoic areas and hypervascularity (p < 0.01, in each). Pleomorphic liposarcomas showed a specific gyrus-like mixture of hyperechoic and hypoechoic areas (p < 0.01). In conclusion, the present study revealed different characteristics of sonographic appearance among the 4 histopathologic subtypes of liposarcoma.

Preoperative Ultrasonographic Evaluation for Malignancy of Soft-Tissue Sarcoma: A Retrospective Study

Background:

Ultrasonography is useful for distinguishing between benign and malignant soft-tissue tumors. However, no study has focused on its usefulness in the differential diagnosis between low-grade and high-grade soft-tissue sarcomas. We conducted a retrospective study to determine the usefulness of the parameters of ultrasonograph and to develop a practical scoring system for distinguishing between high-grade and low-grade sarcomas.

Methods:

Twenty-two cases of low-grade and 43 cases of high-grade malignant soft-tissue sarcoma were enrolled. Ultrasonography parameters including the longest diameter, depth of the tumor, echogenicity, tumor margin, and vascularity defined according to Giovagnorio’s criteria were analyzed as factors to distinguish between the two types of sarcoma. Significant factors were entered into a multivariate model to define the scores for distinction according to the odds ratio. The usefulness of the score was analyzed via receiver operating characteristic analyses.

Results:

In univariate analysis, tumor margin, echogenicity, and vascularity were significantly different between low- and high-grade sarcomas. In the multivariate regression model, the odds ratio for high-grade vs. low-grade sarcoma was 8.8 for tumor margin, 69 for echogenicity, and 8.3 for vascularity. Scores for the risk factors were defined as follows: 1, ill-defined margin; 2, hypoechoic echogenicity; and 1, type IV in Giovagnorio’s criteria. The sum of each score was confirmed by receiver operating characteristic analysis. The area under the curve was 0.95, with a cut-off score of 3, indicating that the scoring system was useful.

Conclusion:

The ultrasonography parameters of tumor margin, echogenicity, and vascularity are useful for distinguishing between low- and high-grade sarcomas.

Preoperative evaluation of intraoperative blood loss during malignant soft tissue tumor resection by ultrasonography

BACKGROUND

Preoperative evaluation of the risk of surgery-related blood loss in malignant soft tissue tumor resection is difficult because of wide variations in histological subtype, malignancy, location, and size. Ultrasonography is useful for the evaluation of blood flow around a soft tissue tumor and has the potential to preoperatively estimate intraoperative blood loss in tumor resection. To date, there has been no report regarding blood loss evaluation using ultrasonography in this field.

PATIENTS AND METHODS

The usefulness of information obtained by ultrasonography, including tumor size, vessel density in the tumor, and blood flow volume in the vessels, was analyzed for the prediction of intraoperative blood loss in malignant soft tissue tumor resection.

RESULTS

Vessel density in the tumor and blood flow in the vessels were identified as independent risk factors for blood loss. Using these factors, a new index for the prediction of blood loss was established. Receiver operating characteristic analyses revealed a high area under the curve value (0.80), confirming the accuracy of the index for the prediction of blood loss.

CONCLUSION

Ultrasonography is a useful modality for predicting intraoperative blood loss in malignant soft tissue tumor surgery.

Groin hernias in adults: value of color Doppler sonography in their classification

PURPOSE

We assessed the abilities of color Doppler and power Doppler sonography to distinguish among types of groin hernias by demonstrating the inferior epigastric artery (IEA) and its relationship with the hernia sac.

METHODS

Nineteen consecutive patients (14 men and 5 women), clinically diagnosed as having groin hernias and scheduled to undergo herniorrhaphy, were prospectively enrolled in this study. Ultrasound examinations were performed preoperatively with a 6-12-MHz linear-array transducer. The IEA was identified, if possible, and its relationship to the hernia sac assessed. The sonographic diagnoses were compared with the operative findings.

RESULTS

There were 15 indirect inguinal hernias, 4 direct inguinal hernias, and 1 femoral hernia; 1 patient had bilateral inguinal hernias (indirect and direct). In 18 (90%) of 20 hernia cases, the trunk segment of the IEA could be visualized. In 11 (55%) of 20 hernia cases, the origin segment of the IEA could be visualized and its relationship with the hernia sac assessed. In 9 (82%) of the 11 hernia cases, hernia types were correctly diagnosed by sonography. The overall accuracy of sonography for diagnosing the type of hernia was 45% (9 of 20 hernias).

CONCLUSIONS

Color Doppler sonography can accurately differentiate types of groin hernias if the origin segment of the IEA and the hernia sac can be visualized simultaneously. However, color Doppler sonography sometimes failed to visualize this segment.