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

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

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

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.

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