Whole-slide imaging for evaluation of double-staining immunocytochemistry in canine lymphomas

Resumen

Lymphoma is the most common hematopoietic neoplasm in dogs, and cytopathology is widely used as a primary diagnostic tool. This evaluation is traditionally performed using light microscopy (LM). Alternatively, digital pathology (DP) is increasingly being adopted in veterinary medicine for cytopathologic diagnosis. However, no studies have evaluated the use of DP for immunocytochemistry (ICC). This study determined the agreement between digital smears and LM in interpreting double-staining ICC (dsICC) in canine lymphoma smears for a single evaluator (intra-observer). The second goal was to assess inter-observer agreement among two evaluators for DP. Twenty-eight Romanowsky-stained smears (RSSs) digitized before and after submission to dsICC underwent whole-slide imaging (WSI) scanning in Standard mode at 400x magnification. Markers CD20 and CD3ε were used for immunophenotyping. Glass and digital smears were evaluated by a single observer before and after dsICC. An additional evaluator independently analyzed the digitized slides. The Kappa Coefficient was used to determine dsICC intra-observer (LM vs Digital) and inter-observer (Digital-only) agreements. Each evaluator correctly phenotyped 24 smears. The intra-observer agreement was almost perfect (k = 0.86; 95% CI, 0.68–1.00). The inter-observer agreement for digital slides was similar (k = 0.87; 95% CI, 0.71-1.00). WSI scans demonstrated high agreement with LM and appear suitable for assessing and determining the immunophenotype of canine lymphomas subjected to dsICC.