Occult carcinoma confirmed to be a diffuse sclerosing variant of papillary thyroid carcinoma with unusual immunohistochemical features: A pitfall of clinicopathological diagnosis.

Immunocytochemistry in a 78-year-old man diagnosed as having systemic metastatic cancer of unknown primary origin revealed atypical cells positive for napsin A and TTF-1, suggesting adenocarcinoma of the lung. However, there was no evidence of a primary lesion in the lung on positron emission tomography/computed tomography or at autopsy. Meanwhile, both the left and right thyroid lobes were firm and grayish white with marked fibrosis. Histology identified a diffuse sclerosing variant of papillary thyroid carcinoma that was positive for TTF-1 and napsin A but negative for PAX8. This disease entity is often misdiagnosed clinically as chronic thyroiditis. This is the first report of napsin A-positive and PAX8-negative thyroid carcinoma and highlights the pitfalls of clinicopathological diagnosis.

A small-scale experimental study of breast FNA consultation on the internet using Panoptiq.

INTRODUCTION: To test the potential for cytopathology consultation using Panoptiq (ViewsIQ, Richmond, BC, Canada; this is a new type of whole-slide image that is made manually and incorporates video content), we investigated its application in the cytopathological diagnosis of cases that were difficult to diagnose by breast fine-needle aspiration (FNA). MATERIALS AND METHODS: Panoptiq files were created from liquid-based cytology slides prepared by the BD CytoRich Red (BD, Franklin Lakes, NJ) method. The slides were prepared from 23 consecutive samples of breast FNA that had been diagnosed as atypical or suspicious by the Hokkaido Cancer Center, Hokkaido, Japan. Nine volunteer reviewers, who were provided with the URL of the Panoptiq file, the original cytopathological diagnosis, and the clinical information, were asked to classify the cytopathological diagnosis of each case into 4 diagnostic categories (benign, atypical, suspicious, or malignant). We examined the consultation benefit (CB)-how much closer the reviewer's cytopathology diagnosis came to the final histopathological diagnosis than the original cytodiagnosis. The CB scoring system was decided in advance. RESULTS: All 9 reviewers showed a positive total CB score and 2 reviewers showed a significantly higher CB score (Wilcoxon's signed rank test). The representative diagnosis (ie, the most frequently rendered diagnosis in each case) also showed a significant CB. CONCLUSIONS: Our small-scale experimental study, in which Panoptiq was used in the diagnosis of cases that were difficult to diagnose definitively by breast FNA, revealed a positive CB score by every reviewer and the representative diagnosis showed a significant CB. The study suggests that Panoptiq could be used for cytopathology consultation.