Presentation
Initially presented with goiter. Found to have abnormal thyroid hormone profile.
Patient Data
Selected images through the thyroid gland demonstrate it to be moderately enlarged, especially on the left, somewhat heterogeneous echotexture. In the isthmus a mixed solid cystic lesion without blood flow (Doppler not shown) is also present.
Images courtesy of Dr Meei Yeung
Macroscopic:
Serial transverse sections through right and left lobes and sagittal sections through isthmus (orientation as marked)
- the gland is enlarged
- the normal tan, fleshy appearance of thyroid parenchyma (residual parenchyma seen in the left lobe) is now seen as pale and homogeneous (R>L)
- sonographically-noted isthmic lesion is identified
- no other suspicious macroscopic lesions
Microscopic:
- low power: extensive replacement of thyroid parenchyma by diffuse reactive lymphoid infiltrate including activated follicles with germinal centers. There is a zone of residual identifiable parenchyma in the top right corner.
- high power: sheets of uniform, small, regular lymphocytes surrounding scattered residual follicles (bottom right).
- there is gross distortion and replacement of normal thyroid microscopic architecture
- the engulfed follicular epithelium often shows associated cytological changes including nuclear activation and cytoplasmic oncocytic/Hurtle cell change
The isthmus cystic lesion was benign on histological examination
Case Discussion
This case illustrates the pathological appearances of Hashimoto thyroiditis, with ultrasound correlate.