Rapid Lump Examination (RLE) - a bedside 3-dimensional microscopy of tumor specimens.

Background: Due to rising skin cancer incidence rates there is an urgent need for a quick, reliable and cost-effective therapy. Previous studies showed that fresh tumor tissue and margins could be directly examined microscopically with high sensitivity and specificity.

Objective: Comparing the accuracy of rapid lump examination (RLE) for the detection of basal cell carcinoma (BCC) during micrographic surgery with formalin-fixed paraffin-embedded hematoxylin and eosin (HE)-stained sections.

Methods And Materials: 382 specimens of 118 excised samples with suspected BCC were examined with RLE and compared with formalin-fixed paraffin-embedded HE-stained sections. For RLE, following a standardized 60 sec staining protocol, the fresh tissue samples were observed directly with a stereomicroscope.

Results: For BCC, RLE had a high but insufficient diagnostic accuracy compared to the gold standard of formalin-fixed paraffin-embedded HE-stained sections. The sensitivity was 76 % (95 % CI = [66.18 %; 84.5 %]) and specificity was 91 % (95 % CI = [86.73 %; 93.75 %]).

Conclusions: RLE is a fast and simple technique for microscopically controlled surgery (MCS) of basal cell carcinomas that requires training. The experience of the examiner has a major influence on the results. RLE has great potential to speed up the workflow in Mohs surgery but should be improved in the future.