Dermatopathology specialists may render higher-grade diagnoses for low risk melanomas

Key takeaways:

• Pathologists specializing in dermatopathology tended to give higher-grade diagnoses vs. those without training (OR = 2.63).
• They were also more likely to give invasive melanoma diagnoses (OR = 1.95).

Specialty training in dermatopathology correlated with a greater tendency to diagnose low risk melanomas as more severe, according to a study.

“Melanocytic lesions are challenging for pathologists to interpret, with extensive levels of interobserver and intraobserver variability,” Kathleen F. Kerr, PhD, of the department of biostatistics at University of Washington, and colleagues wrote. “In addition, epidemiologic data show steady increases in melanoma diagnoses over recent decades, without significant change in melanoma mortality.”

In this exploratory study, researchers assessed the association between pathologist characteristics and tendencies to diagnose melanocytic lesions as higher grade vs. lower grade.

The study used data from two nationwide studies that were conducted from 2013 to 2016 and 2018 to 2021, respectively, in which pathologists interpreted melanocytic lesions in glass slide format. Of 338 total participating pathologists, 113 were general pathologists, whereas 225 were dermatopathologists.

Results showed that specialized training in dermatopathology was most highly associated with rendering a more severe diagnosis. Pathologists with dermatopathology training were more likely to give higher-grade diagnoses (OR = 2.63; 95% CI, 2.1-3.3) and invasive melanoma diagnoses (OR = 1.95; 95% CI, 1.53-2.49) compared with pathologists without this training.

Dermatopathologists with a practice that handled a higher volume of melanocytic lesions tended to assign higher-grade diagnoses than their counterparts (OR = 1.27; 95% CI, 1.04-1.56). More specifically, dermatopathologists were more likely to diagnose low risk, nonmitogenic pT1a lesions as invasive melanoma. Once these low-risk diagnoses were regrouped with other less severe diagnoses, there was no association between dermatopathologists and high-grade diagnoses (OR = 0.95; 95% CI, 0.74-1.23).

“Specialization in dermatopathology was associated with rendering more severe diagnoses for skin biopsy cases of melanocytic lesions,” Kerr and colleagues wrote. “We hypothesize that this could in part play a role in the rising incidence of early-stage melanoma with low risk of progression or patient morbidity, thereby contributing to increasing rates of overdiagnosis.”