Secondary review of external histopathology on cutaneous oncology patients referred for sentinel lymph node biopsy: how often does it happen and is it worth it?

Background We reviewed the data on external histopathology review for patients referred to our institution for sentinel lymph node biopsy (SLNB) associated with melanoma, Merkel cell carcinoma and adnexal carcinoma. Methods We calculated the incidence of external histopathology review and the rate of discordance between internal and external histopathology diagnoses between January 1, 2010 and February 28, 2011. We conducted an anonymous poll of our community pathologists' experience with external histopathology review prior to SLNB. Financial charges and payments from 10 Medicare patients who underwent SLNB were obtained from our hospital's finance department. Results Sixty-eight cases were identified (63 melanomas, 4 Merkel cell carcinomas and 1 spiradenocarcinoma). The external histopathology was reviewed as part of the patient's care in 14 of 68 cases. In 3 of 14 reviewed cases, SLNB was deemed unnecessary. Nine of eleven community pathologists reported reviewing external histopathology material in less than 11% SLNB patients in their hospitals. The average Medicare reimbursement for SLNB and secondary pathology review was $5738 and $80 respectively. Conclusions Our data show that review of external cutaneous histopathology diagnoses on patients referred for SLNB is uncommon in our practice area, but is cost-effective and should be required to reduce unnecessary treatment.