SLR - January 2010 - Marcie Zdarko
Reference:
Kuwano, Y., Kazuho, I., Watanabe, R., Nanko, H. (2009). Efficacy of diagnostic ultrasonography of lipomas, epidermal cysts, and ganglions. Arch Dermatol, 145(7), 761-764.
Scientific Literature Reviews
Reviewed by: Marcie Zdarko, DPM
Residency Program: Kaiser North Bay Consortium, Vallejo
Podiatric Relevance:
Soft tissue masses commonly present in the foot and ankle, and thus are treated by foot and ankle surgeons. Upon clinical exam, if the mass appears benign but is a source of pain, it commonly is surgically excised. Many times the surgeon can predict the underlying diagnosis prior to excision from clinical exam, however, the surgeon is not always accurate. Ultrasonography is a noninvasive, rather non-expensive method of examination that is useful for acquiring information regarding the nature, size, and depth of the lesions as well as their relationship to adjacent structures. Therefore, ultrasonography can be a tool for the foot and ankle surgeon that can provide further diagnostic information prior to surgical excision, which may be utilized on pre-operative exam.
Methods:
This retrospective study consisted of 183 patients with subcutaneous benign lesions who underwent ultrasonography and received a pathologic diagnosis after surgery. The study was performed at Tokyo Kousei-Nenkin Hospital, Tokyo, Japan, from 1998-2006. Patients with malignant subcutaneous tumors were not included. The patients were examined clinically, and the suspected clinical diagnosis was written on the medical record. Ultrasonography was then performed with 8.5-MHz linear transducer. The diagnosis after ultrasonography was then written on the medical record before surgery. Preoperative diagnosis after palpation and after ultrasonagraphy were then compared to pathologic diagnosis. An elongated isoechoic mass with striated echoes corresponding to the septa in the subcutaneous tissues was diagnosed as a lipoma. A round to oval nonanechoic mass with partial indentation to the dermis and with dorsal acoustic amplification was diagnosed as an epidermal cyst. An anechoic amorphous mass with a relatively sharp border and joint communication was diagnosed as a ganglion.
Results:
The number of cases in which the preoperative diagnosis correlated with the pathologic diagnosis was significantly higher after ultrasonagraphy (46%) than after palpation alone (29%; P<.001). The sensitivity and specificity for the diagnosis of each soft tissue mass was also investigated. In the setting of lipoma, the sensitivity after ultrasonography was significantly higher than after palpation alone (after palpation, 54.8%; after ultrasonography, 88.1%; P<.01). With regards to epidermal cyst, the sensitivity was higher after ultrasonography (after palpation, 43.2%; after ultrasonography, 65.9%). The sensitivity was also higher after ultrasonography for ganglion (after palpation, 27.8%; after ultrasonography, 38.9%). It was further demonstrated that the specificity after ultrasonography was significanlty higher for epidermal cyst (after palpation, 93.5%; after ultrasonography, 99.3%; P<.05). The specificity was higher for both lipoma and ganglion following ultrasound, but was not found to be significant.
Conclusions:
This retrospective study demonstrated a statistically significant increase in the preoperative diagnostic yield of subcutaneous benign lesions with use of ultrasonography when compared to palpation alone. While ultrasonography did not provide an accurate diagnosis in every case, this study illustrates it is a noninvasive method that can assist the surgeon with their preoperative examination of these soft tissue masses.