Thyroid and parathyroid

Question 1

Thyroid tumour with papillae lined by cells with papillary nuclear features. These are usually interspersed with neoplastic follicles comprised of the same cells, containing thick ‘bubble gum’ colloid.

Answer 1

Papillary thyroid carcinoma

Differential diagnosis: Graves disease

Plan:
Correlate with clinical history and radiology (?pre-operative FNA)
Examine further sections (e.g. for total size, relation to margins, LVI, LNs etc)
IPX to support Dx: TTF1, thyroglobulin, PAX8; also BRAFV600E
Next steps: Synoptic report, discuss at MDT

Question 2

Unencapsulated thyroid lesion with follicular architecture but papillary nuclear features. Follicles contain thick ‘bubble gum’ colloid

Answer 2

Infiltrative follicular variant of papillary thyroid carcinoma

Differential diagnosis: Papillary thyroid carcinoma, classic type

Plan:
Correlate with clinical history and radiology (?pre-operative FNA)
Examine further sections (e.g. for total size, relation to margins, LVI, LNs etc. Also need to examine for any classic PTC, as any papillary areas would redesignate tumour as classic type)
IPX to support Dx: TTF1, thyroglobulin, PAX8; also BRAFV600E
Next steps: Synoptic report, discuss at MDT

Question 3

Thyroid lesion with finely dispersed stippled chromatin and stromal amyloid accumulation. There is often lymphovascular invasion.

Answer 3

Medullary thyroid carcinoma

Plan:
Correlate with clinical history and radiology (?pre-operative FNA)
Examine further blocks (e.g. for total size, relation to margins, LVI)
Special stains: Congo red (to highlight stromal amyloid)
IPX to support Dx: Synaptophysin, chromogranin, calcitonin
Next steps: Synoptic report, discuss at MDT
Advice to clinician: May be sporadic or assiociated with familial syndrome (e.g. MEN2a or MEN2b). Clinical correlation is required.

Question 4

Thyroid with lymphoplasmacytic infiltrate with germinal center formation, and small atrophic follicles with Hürthle cell change (oncocytic change).

Answer 4

Hashimoto thyroiditis

Plan:
Correlate with clinical history and radiology (?hypothyroidism ?thyroid autoantibodies)
Examine further sections (e.g. for concurrent neoplastic pathology)
This is a morphological diagnosis of a benign entity; no specific further action is required.

Question 5

Thyroid with diffuse hyperplasia of follicular epithelium resulting in papillary projections into lumen, but cells lack papillary nuclear features. Colloid is scant in untreated cases, but when treated (more common) is seen. Colloid is typically pale and shows scalloping.

Answer 5

Grave’s disease

Plan:
Correlate with clinical history and radiology (?hyperthyroidism ?TSH autoantibodies ?opthalmopathy)
Examine further sections (e.g. for concurrent neoplastic pathology)
This is a morphological diagnosis of a benign entity; no specific further action is required

Question 6

Thyroid with multiple ‘adenomatoid nodules lacking true capsule, containing large follicles distended with colloid, which can show papillary infoldings and ‘Sanderson polsters’ - clusters of small subfollicles projecting into the lumen.

Answer 6

Thyroid follicular nodular disease

Plan:
Correlate with clinical history and radiology (?goitre ?USS findings ?pre-operative FNA)
Examine further blocks
This is a morphological diagnosis of a benign entity; no specific further action is required.

Question 7

Well circumscribed nodule of fat depleted parathyroid tissue, with compressed non-neoplastic tissue at edge. Most commonly composed of chief cells ( round nucleus, little granular cytoplasm)

Answer 7

Parathyroid adenoma

Differential diagnosis:
Parathyroid hyperplasia
Paraganglioma

Plan:
Correlate with clinical history and radiology (?hyperparathyroidism ?Sestamibi scan showing discrete lesion vs 4 gland hyperplasia ?renal disease ?post-operative PTH/Ca levels)
IPX to support Dx: PTH
This is a benign entity, no specific further action is required