Soft Tissue Masses in the Extremities: The Accuracy of an Ultrasonographic Diagnosis

An, Ji Young; Park, So Young; Park, Ji Seon; Jin, Wook; Ryu, Kyung Nam

Abstract

PURPOSE
We wanted to retrospectively determine the accuracy of an ultrasonographic diagnosis of superficial soft tissue masses in the extremities by using the histologic results as the reference standard.
MATERIALS AND METHODS
From January 2005 to June 2010, 154 patients with soft tissue masses in the extremities and who underwent ultrasonographic evaluation followed by biopsy or resection were retrospectively evaluated. The ultrasonographic and histologic diagnoses of the soft tissue masses were lipoma, ganglion cyst, hemangioma, neurogenic tumor, giant cell tumor of the tendon sheath, epidermoid cyst, fibroma, glomus tumor, Baker's cyst and neurofibromatosis.
RESULTS
Out of 154 patients, 114 (74%) patients showed concordance between the histologic diagnosis and the ultrasonographic diagnosis, and the remaining 40 (26%) patients did not. The diagnostic accuracy of each soft tissue mass was 95% for lipoma, 83% for ganglion cyst, 75% for hemangioma, 72% for neurogenic tumor, 50% for giant cell tumor of the tendon sheath, 43% for epidermoid cyst, 33% for fibroma and 100% each for glomus tumor, fibromatosis and Baker's cyst. Aside from these tumors, there were also sarcoma, malignant melanoma, elastofibroma, Kimura disease and pilomatricoma. Among the cases that showed discordance between the histologic diagnosis and the ultrasonographic diagnosis, three of them were notable; pilomatricoma being misdiagnosed as dermatofibroma protuberans, angiolipoma being misdiagnosed as vascular leiomyoma and malignant fibrous histiocytoma being misdiagnosed as a malignant soft tissue mass.
CONCLUSION
The accuracy of an ultrasonographic diagnosis for soft tissue masses in the extremities varies greatly according to each type of mass. Lipoma, ganglion cyst, hemangioma, glomus tumor, neurogenic tumor and Baker's cyst showed a relatively high rate of concordance between the ultrasonographic diagnosis and the histologic diagnosis, but epidermoid cyst and fibroma showed a relatively lower rate of concordance.