Thyroid Adenoma

Common sites:

Gross features:

• solitary
• spherical
• encapsulated
• average 3cm
• gray-white to red-brown
• may have areas of hemorrhage, fibrosis, calcification, or cystic change

Histologic features:

• well demarcated from the adjacent parenchyma by an intact capsule (MOST IMPORTANT), and in general appearance
• uniform-appearing/homogenous follicles containing colloid
• little variation in cell and nuclear morphology
• occasionally may have focal nuclear pleomorphism, atypia, and prominent nucleoli
• rare mitoses
• Hurthle cell adenoma (variant)
• brightly eosinophilic cytoplasm
• small, regular nuclei
• Follicular adenoma with papillary architecture:
• Papillary architecture with “intrafollicular papillae” as seen in Grave’s disease
• Scalloped edges of colloid
• Hemosiderin accumulation in ends of epithelial cells
• Hyperfunctioning, “hot” nodule on imaging
• Caused by constituent activation of the TSH receptor (ex. Grave’s disease, familial mutations)

Immunophenotype:

Marker:

Sensitivity:

Specificity:

Molecular features:

Other features:

• Familial syndromes:
• McCune-Albright
• abnormal bone development
• endocrine disorders
• Café au lait spots