[Benign Subcutaneous Nodules for the Diagnosis of Which Ultrasonography Is Useful].

Objective: We analyzed sonographic appearance of dermatofibroma, schwannoma, small-sized venous mal- formation, glomus tumor, nodular fasciitis, and thrombus for effective use in the diagnosis.

Methods: We evaluated with sonography 44 subcutaneous nodules in histopathologically proven cases.

Results and discussion: 1) Sonography was the most useful for diagnosing schwannoma. Six of 8 lesions were diagnosed correctly from sonographic appearance. They had increased posterior echo and Doppler flow signals. 2) Sonography was helpful in diagnosis of subungual glomus tumor, though malignant melano- ma should be excluded. One of 6 glomus tumors was not detected but all of the other had well-defined mar- gins and showed internal vascularity. Three subungual glomus tumors were diagnosed from sonographic appearance although 2 nonsubungual tumors were not. 3) It was difficult to diagnose nodular fasciitis with sonography. Two of 5 cases were not detected. The other 3 lesions were ill-defined, and 2 were hy- perechoic and 2 showed internal vascularity. Interval between emergence of the lesion and sonography ex- amination was important. This duration was more than 50 days in lesions not detected with sonography, about 20 days in 2 hyperechoic lesions, and 6 days in a hypoechoic lesion. 4) Dermatofibromas (n =14) were also difficult to be diagnosed. The region was very characteristic, that is, in the upper dermis. Other find- ings, such as hypoechoic appearance and well-defined margin, were nonspecific.

Conclusion: Sonography was more useful for diagnosing schwannoma and glomus tumor. We have to know their characteristic appearance on sonography to use sonography effectively. [Original].