50-year-old female, slowly growing symmetrical goitre, painless, insidious onset of hypothyroidism. Excision of goitre due to breathing difficulties.
- The thyroid tissue contains a diffuse lymphocytic infiltrate with lymph follicle formation.
- The thyroid follicle is partly destroyed and forms strands consisting of follicle epithelial cells with oncocytic metaplasia.
- Many B-lymphocytes and plasma cells with brown reaction product can be seen.
- Unspecific brown staining of scarce colloid
Immunological hypersensitivity reaction type II: cytotoxic destruction of follicle epithelial cells; resulting in hyperthyroidism since the entire thyroid gland is affected.