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

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

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 areas of classic PTC, as presence of any papillary areas would redesignate tumour as classic PTC)
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

Name for clusters of subfollicles within adenomatoid nodules

Answer 7

Sanderson polsters

Question 8

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 8

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

Question 9

Well circumscribed thyroid tumour, with trabeculae surrounded by hyaline basement membrane material. Cells are large with eosinophilic cytoplasm and elongated nuclei with grooves and intranuclear inclusions. A classic feature yellow perinuclear inclusions ‘yellow bodies’

Answer 9

Hyalinising trabecular tumour

Differential diagnosis
Medullary thyroid carcinoma
Paraganglioma

Plan
Correlate with clinical features and radiology (?preoperative FNA)
IPX to support Dx: Ki67 (expect membranous staining with MIB1 antibody)
IPX to discount DDx: Calcitonin, chromogranin
Advice to clinician: Almost all cases show benign clinical course

Question 10

Thyroid with lymphocytes, histiocytes, and foreign body giant cells, with poorly formed non-necrotizing granulomas, and patchy fibrosis.

Answer 10

Granulomatous thyroiditis (De Quervain thyroiditis)

Differential diagnosis:
Infection (tuberculosis)
Involvement of thyroid by sarcoidosis

Plan:
Correlate with clinical history and radiology (?systemic illness)
Correlate with any concurrent microbiology investigations
Examine further blocks
Special stains: AFB (ZN / modified ZN), gram, PAS, GMS (to look for infection)
Advice to clinician: Usually a self limited illness

Question 11

Thyroid with patchy lymphoplasmacytic inflammation, ‘storiform fibrosis’ progressing to dense hyaline collagenization, and ‘obliterative phlebitis’ referring to inflammation of veins, with thrombosis and ultimately destruction of the lumen.

Answer 11

Reidel thyroiditis (IgG4 related thyroid disease)

Differential diagnosis:
IgG4 related Hashimoto thyroiditis

Plan:
Correlate with clinical history, radiology and gross macroscopic findings (?involvement of perithyroidal soft tissue)
Examine further blocks
IPX to support Dx: IgG, IgG4 (showing increased IgG4 + plasma cells)