Thyroidectomy specimen from an 18-year-old woman with diffuse goitre, exophthalmos and pretibial myxoedema shows diffusely hyperplastic follicles lined by tall columnar epithelium with crowded nuclei, and pale colloid with peripheral 'scalloping'. The scalloped appearance of the colloid is due to:

• A Deposition of amyloid at the colloid interface
• B Compression of follicles by lymphoid aggregates
• C Coagulative necrosis of colloid from antibody-mediated injury
• D Rapid resorption of thyroglobulin by hyperactive follicular cells ✓

Explanation

In Graves disease, thyroid-stimulating immunoglobulins bind the TSH receptor and drive continuous synthesis and secretion of hormone. Hyperactive follicular cells rapidly endocytose thyroglobulin, creating clear resorption lacunae that scallop the edges of the pale, watery colloid. Amyloid deposition occurs in medullary carcinoma, coagulative necrosis is not a feature here, and lymphoid compression does not produce this pattern.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.