THYROID LEASIONS

1. Practical-3
Thyroid Pathology
2018

2. Diffuse Enlargement GD
•Most common disease of thyroid
gland
•Diffuse or nodular enlargement with
distorted outer surface
•Grossly visible in 10% of thyroid
glands at autopsy but microscopic
nodularity is present in 40%
•May cause compression of trachea.
•3 - 5% risk of thyroid cancer,
predominantly follicular variant of
papillary thyroid carcinoma

3. Graves Disease
• Hyperplastic thyroid follicles with papillary
infoldings
• Diffuse hyperplasia and hypertrophy of
follicular cells with retention of lobular
architecture and prominent vascular
congestion
• Tall follicular cells with papillae usually lacking
fibrovascular cores
• Nuclei are round, often basally located, rarely
overlap
• Colloid is typically decreased, when present
shows peripheral scalloping
• Variable patchy lymphoid infiltrate in the
stroma
• Rarely small clusters of normal thyroid
follicles in adjacent lymph node sinuses

4. Hashimoto Thyroditis
•Extensive lymphocytic infiltrate with
germinal center formation
•Lymphocytes are predominantly T
cells and plasma cells
•Atrophic follicles with abundant
Hürthle cells / oncocytes.
•May see giant cells
•Squamous metaplasia of follicular
epithelium can be seen.
•Occasionally nodular appearance.

5. MNG

6. MNG
• Simple goiters are usually firm with amber cut surface
• Multinodular goiters are asymmetric, large, up to 2 kg, cystic and
hemorrhagic with brown gelatinous colloid nodules with focal
calcification
• Capsule is usually intact and surface is bumpy

7. MNG
•Variable sized dilated follicles with flattened
hyperplastic epithelium
•Nodules may be present but without thick
capsule
•Secondary changes may be seen, including
foci of fresh or old hemorrhage, rupture of
follicles with granulomatous response, fibrosis,
calcification and even osseous metaplasia
•Some of the cystically dilated follicles may
show papillary projections (Sanderson polsters)
that may mimic papillary carcinoma; however,
they lack the nuclear features of papillary
carcinoma

8. Follicular Adenoma
•Solitary, encapsulated, variable
size (1 - 10 cm)
•Solid, fleshy, tan to light brown
•Bulges when fresh, compresses
adjacent thyroid
•Resembles multinodular goiter
due to secondary changes of
hemorrhage and cystic
degeneration

9. • Completely enveloped by thin fibrous capsule
• Architecturally and cytologically different from surrounding
gland; surrounding thyroid tissue shows signs of
compression
• Closely packed follicles, trabeculae or solid sheets
• Patterns:Normofollicular (simple)
• Macrofollicular (colloid): large colloid filled follicles with
flattened epithelium
• Microfollicular (fetal): small follicles, may have signet ring
cell features
• Trabecular / solid (embryonal): cords / trabeculae with few
follicles
• May have focal papillary pattern Mitoses are uncommon
• Cuboidal to low columnar cells, pale staining with round
inconspicuous nucleoli
• Commonly secondary changes of hemorrhage, hemosiderin
deposition, sclerosis, edema, necrosis and cystic changes
• No capsular or vascular invasion after thorough sampling (at
least 10 blocks), no / rare mitotic figures, no papillary
nuclear features

10. Papillary Carcinoma
• Solid, white, firm, often
multifocal (20%), encapsulated
(10%) or infiltrative
• Variable cysts, fibrosis,
calcification

11. •Complex, branching, randomly oriented
papillae with fibrovascular cores associated
with follicles
•Usually dense fibrosis
• Papillae lined by cuboidal cells, nuclei are
overlapping with finely dispersed optically clear
chromatin (also called ground glass, Orphan
Annie nuclei, not seen in cytology or frozen
section material, Stromal elastosis in 66%
•Psammoma bodies:
In 50% of tumors in papillary stalk in fibrous stroma
between tumor cells (usually not in neoplastic
follicles)
Due to tumor cell necrosis
Fairly specific but may also be seen in metastasis

12. Follicular Carcinoma
•Tan to brown solid cut surface, can
have cystic changes and
hemorrhage
•Minimally invasive: usually single
encapsulated nodule, with thickened
and irregular capsule
•Widely invasive: extensive
permeation of capsule or no capsule
•All capsule with adjacent tissue
needs to be submitted for
histological evaluation

13. Follicular Carcinoma
•Trabecular or solid pattern of follicles (- microfollicular, normofollicular or macrofollicular)
•No nuclear features of papillary thyroid carcinoma
•Invasion of adjacent thyroid parenchyma, capsule (complete penetration) or blood vessels (in or beyond the
capsule)
•Capsular invasion: capsule is typically thickened and irregular, needs penetration through the capsule (full
thickness)
•Vascular invasion: vessel within or beyond the capsule.
•May have nuclear atypia, focal spindled areas, mitotic figures (< 3/10HPF)
•No necrosis

14. Medullary Carcinoma- Congo Red Stain Positive Amyloid
• Sporadic: typically presents as a single
circumscribed but nonencapsulated, gray-
tan mass
• Familial: generally bilateral / multiple foci
• Solid, gray-tan-yellow, firm, may be
infiltrative
• Larger lesions have hemorrhage and
necrosis, tumor usually in mid or upper
portion of gland (with higher density of C
cells)
• < 1 cm in size is called microcarcinoma; if <
0.5 cm, associated with a complete absence
of clinically detectable metastatic disease

15. Medullary Carcinoma- Congo Red Stain Positive Amyloid
• Round, plasmacytoid, polygonal or
spindle cells in nests, cords or
follicles
• Round nuclei with finely stippled to
coarsely clumped chromatin and
indistinct nucleoli, occasional nuclear
pseudoinclusion
• Eosinophilic to amphophilic granular
cytoplasm.
• Generally low mitotic figures
• Stroma has amyloid deposits from
calcitonin, prominent vascularity
with glomeruloid configuration or
long cords of vessels