Criteria for the Histological Diagnosis

· Non-solid variant of PTC

· ≤10% of the tumor showed tall/columnar cell or diffuse sclerosing features

· Loss of polarity/cohesiveness with hobnail features in ≥ 30% of tumor cells

· PTC features are present showing papillary and micro papillary structures in the histopathologic smears

· High magnification shows nuclear pleomorphism, occasionally pseudo-inclusions with multiple soap bubble-like inclusions, and possibly mitotic figures

· Along with the PTC cellular findings HPTC can show papillary and micro papillary structures closely linked by cells containing eosinophilic cytoplasm and apically located nuclei with prominent nucleoli

· The cells that line these complex papillary structures have increased nuclear to cytoplasmic ratios and apically placed nuclei that produce a surface bulge (hobnail)