Parathyroid adenoma resection sample. The sample weighed 0.3 g. We observed densely hyperplastic chief primary cells without fat cells. No atypia or evidence of infiltration is seen. Although a normal rim cannot be seen, the sample was considered a parathyroid adenoma based on the enlargement of one gland. A (Left): ×4; B (Right): ×10. Hematoxylin and eosin staining.