Wan-Chen Tsai MD, Presenter: Nothing to Disclose

Hong-Jen Chiou MD, Abstract Co-Author: Nothing to Disclose

Yi-Hong Chou MD, Abstract Co-Author: Nothing to Disclose

Hsin-Kai Wang MD, Abstract Co-Author: Nothing to Disclose

See-Ying Chiou MD, Abstract Co-Author: Nothing to Disclose

Cheng-Yen Chang MD, Abstract Co-Author: Nothing to Disclose

To evaluate if high-resolution ultrasound (HRUS) and Color Doppler ultrasound (CDUS) could differentiate schwannoma from neurofibroma, which may change the surgical management, either mass enucleation or nerve re-implantation.

71 patients (76 tumors) including 46 patients (50 tumors) with schwannoma and 25 patients (26 tumors) with non-diffuse type neurofibroma in extremities or superficial body were enrolled in this study from May 1999 to March 2006. All patients underwent HRUS examinations with focus on the size, shape, location, association with nerve (central or eccentric), capsule, internal echogenecity, posterior acoustic shadowing or enhancement, cystic change or not. Color Doppler studies and spectrum analysis were performed in most patients. All data were calculated the significance with SPSS for windows 12.0.

Both tumors presented as well defined with echogenic capsule, hypoechoic, ovoid or lobulated in shape, hypervascular and showing posterior acoustic enhancement without significant difference. The numbers of association with nerve (centric, eccentric, or no association) were 20,10 and 20 in schwannoma and 12, 0 and 14 in neurofibroma with significant difference (p=0.032). There was no significant difference in the chance of cystic change between the schwannoma (30%) and neurofibroma (23%). The mean resistance index (RI) max in schwannoma was 0.914 and in neurofibroma was 0.748 with statistical significance (p=0.013).

Both eccentric to associated nerve and higher RI are more common in schwannoma. Cystic degeneration is not rare in both schwannoma and neurofibroma.

HRUS with CDUS could play a role in differentiation between schwannoma and neurofibroma in extremities and superficial trunk before surgery.

Tsai, W, Chiou, H, Chou, Y, Wang, H, Chiou, S, Chang, C, Differentiation between Schwannoma and Neurofibroma in Extremities and Superficial Body: The Role of High Resolution Ultrasonography.  Radiological Society of North America 2006 Scientific Assembly and Annual Meeting, November 26 - December 1, 2006 ,Chicago IL. http://archive.rsna.org/2006/4434023.html