11 | Challenges in developing a digital pathology consultation network: insights from the MELCAYA experience

Filippo Ugolini¹, Dario Di Gangi², Roberta Gugliotta³, Anna Szumera-Ciećkiewicz^4|5, Llucia Alos⁶, Natalia Castrejón⁶, Stephan Forchhammer⁷, Barbara Valeri⁸, Nicolas Macagno⁹, Sule Ozturk Sari¹⁰, Ozge Hurdogan¹⁰, Sokol Sina¹¹, Sylvie Fraitag¹², Valerio Gaetano Vellone¹³, Chiara Trambaiolo¹³, Rita Alaggio¹⁴, Sabrina Rossi¹⁴, Giovanni Arcuri³, Daniela Massi², Claudio Conti³ | ¹Histopathology and Molecular Diagnostics, Careggi University Hospital, Florence, Italy. ²Section of Pathological Anatomy, Department of Health Sciences, University of Florence, Florence, Italy. ³UOC Direzione Tecnica, ICT ed Innovazione Tecnologie Sanitarie, Fondazione Policlinico Agostino Gemelli IRCCS, Roma, Italy. ⁴Biobank, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland. ⁵Department of Pathology , Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland. ⁶Department of Pathology, Hospital Clínic of Barcelona, University of Barcelona, Barcelona, Spain.⁷Department of Dermatology, University Medical Center, Eberhard Karls University Tübingen, Tübingen, Germany. ⁸Pathology Department, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. ⁹Aix-Marseille University, Marmara Institute, INSERM, U1251, MMG, DOD-CET, Marseille, France. ¹⁰Department of Pathology, Istanbul University Istanbul Medical Faculty, Istanbul, Türkiye; ¹¹Section of Pathology, Department of Diagnostics and Public Health, University of Verona, Verona, Italy. ¹²Pathology Department, Necker-Enfants Malades Hospital, AP-HP, Paris, France; ¹³Pathology Unit, IRCCS Istituto Giannina Gaslini, Genoa; ¹⁴Pathology Unit, Department of Laboratories, Bambino Gesu Children's Hospital, IRCCS, Rome, Italy.

Background: The increasing adoption of Whole Slide Image (WSI) technology has created new opportunities for collaboration in diagnostic pathology. This study aims to describe the development, implementation, and challenges of establishing a second-opinion platform for pathology revision, focusing on improving the diagnostic assessment of melanoma in children, adolescents, and young adults (CAYA).

Methods: Two-hundred-eight melanomas and atypical melanocytic lesions from CAYA patients were retrospectively collected, resulting in 311 associated WSIs. Recognizing the rarity of these cases, patient enrollment was distributed across 11 centers spanning 6 European countries. All slides were digitalized at each participating institution and uploaded into a centralized digital platform to be reviewed.

Results: A total of 144 WSIs (46.3%) exhibited technical defects, classified as critical, major, or minor based on their impact on WSI quality and visualization. Of these, 101 (70.1%) showed analytical defects, while the remaining 43 (29.9%) presented pre-analytical issues. Significant inter-center variability in file sizes was observed, reflecting differences in scanning protocols and tissue processing. Twenty-four cases (11.5%) exhibited major discordances on melanoma vs atypical melanocytic lesions classification, underscoring the importance of centralized pathological review.

Conclusions: This study highlights the challenges of obtaining standardized, high-quality WSIs in real-world settings, particularly due to the rarity of the disease and the limited availability of tissue. These findings reinforce the importance of establishing standardized protocols across institutions to provide pathologists with a high-quality repository and improve patient outcome through effective second-opinion reviews.