Ultrasound/fine-needle aspiration diagnoses melanoma metastases

Ultrasound plus confirmatory fine-needle aspiration cytology can reliably diagnose melanoma metastases, including those less than 6 mm in diameter. Use of the technique enabled over 12% of patients with lymph node metastases to undergo immediate lymph node dissection without the need for prior sentinel node dissection, according to a German study presented at the 2005 American Society of Clinical Oncology meeting in Orlando.

Dr. Christiane Voit and colleagues from Humboldt University in Berlin reported data for 835 melanoma patients who had lesions detected by ultrasound and then confirmed by ultrasound-guided fine-needle aspiration cytology (FNAC).

The combination was tested as a diagnostic standard for verification of tumor spread in melanoma and in 260 patients with cutaneous lymphoma. Data were confirmed by long-term follow-up in 635 patients.

In 1419 procedures performed, FNAC established the correct diagnosis with a sensitivity of 97.9%, specificity of 99.8%, positive predictive value of 99.9%, and negative predictive value of 95.7%. The procedure was also relatively easy for both patients and clinicians, Voit said.

Diagnosis of lesions smaller than 6 mm could be verified with a sensitivity of 96.6% and a specificity of 100%.

The researchers also tested ultrasound plus confirmatory ultrasound-guided FNAC for predicting sentinel node involvement in 121 melanoma patients. They found that 15 of the 121 histologically/immunohistologically proven involved sentinel nodes were detected by the combination of ultrasound and FNAC. Six of 121 exams were false negatives, but three of those six showed few and only immunohistologically positive cells.

"Maximum asymmetrical cortex thickness combined with irregular hypervascularization turned out to be the most important feature to predict sentinel node involvement," Voit said.

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