Mastering Medical
USMLE Step 1 · Endocrine

Differentiated thyroid carcinoma patterns vs Medullary and anaplastic thyroid carcinoma patterns

How to tell Differentiated thyroid carcinoma patterns and Medullary and anaplastic thyroid carcinoma patterns apart when a board question makes them look alike.

Fastest separator

Papillary is nuclei/psammoma/lymphatics; follicular is capsular-vascular invasion/hematogenous spread; medullary is C cells/calcitonin/amyloid; anaplastic is rapidly fatal undifferentiated mass.

Side by side

Differentiated thyroid carcinoma patternsMedullary and anaplastic thyroid carcinoma patterns
Key clue

Papillary thyroid carcinoma has Orphan Annie eye nuclei, optically clear nuclei, psammoma bodies, radiation risk, and lymphatic spread; follicular carcinoma invades capsule/vessels and spreads hematogenously.

Medullary carcinoma arises from parafollicular C cells with calcitonin and amyloid; anaplastic carcinoma is rapidly enlarging, undifferentiated, aggressive thyroid cancer in older adults.

Mechanism

Follicular-cell derived cancers retain thyroid differentiation; papillary spreads by lymphatics while follicular spread requires capsular or vascular invasion.

Medullary carcinoma is neuroendocrine C-cell malignancy often linked to RET; anaplastic carcinoma is dedifferentiated and locally invasive.

Labs and tests

Psammoma bodies and nuclear grooves support papillary; capsular or vascular invasion supports follicular carcinoma.

Calcitonin and amyloid stroma support medullary; rapidly enlarging hard neck mass with compressive symptoms supports anaplastic carcinoma.

The trap

All are thyroid cancers, but cell origin, histology, spread route, and age/aggressiveness split them.

The repair move

For thyroid cancer, match the histology to the spread route and tumor marker before naming the subtype.

Try a free question

Core

A young woman with prior neck radiation has a thyroid nodule and cervical lymph node metastasis. Histology shows papillary structures, nuclear grooves, optically clear nuclei, and psammoma bodies. Which cancer is most likely?

Show answer and explanation

Answer: A. Papillary thyroid carcinoma. Papillary architecture, characteristic nuclei, psammoma bodies, and lymphatic spread point to papillary thyroid carcinoma.

Why the other choices are tempting

  • B. Follicular carcinoma is defined by capsular or vascular invasion and hematogenous spread.
  • C. Medullary carcinoma arises from C cells and produces calcitonin with amyloid stroma.
  • D. Anaplastic carcinoma is rapidly aggressive in older adults.
  • E. Follicular adenoma lacks capsular and vascular invasion and does not metastasize.

Flashcards

Tap a card to flip it.

What histology points to papillary thyroid carcinoma?

Nuclear grooves, optically clear nuclei, papillary structures, and psammoma bodies point to papillary carcinoma.

What feature diagnoses follicular carcinoma rather than adenoma?

Capsular or vascular invasion diagnoses follicular carcinoma.

Quick answers

What is the fastest way to tell Differentiated thyroid carcinoma patterns from Medullary and anaplastic thyroid carcinoma patterns?

Papillary is nuclei/psammoma/lymphatics; follicular is capsular-vascular invasion/hematogenous spread; medullary is C cells/calcitonin/amyloid; anaplastic is rapidly fatal undifferentiated mass.

What is the key clue for Differentiated thyroid carcinoma patterns?

Papillary thyroid carcinoma has Orphan Annie eye nuclei, optically clear nuclei, psammoma bodies, radiation risk, and lymphatic spread; follicular carcinoma invades capsule/vessels and spreads hematogenously.

What is the key clue for Medullary and anaplastic thyroid carcinoma patterns?

Medullary carcinoma arises from parafollicular C cells with calcitonin and amyloid; anaplastic carcinoma is rapidly enlarging, undifferentiated, aggressive thyroid cancer in older adults.

What is the common trap with Differentiated thyroid carcinoma patterns vs Medullary and anaplastic thyroid carcinoma patterns?

All are thyroid cancers, but cell origin, histology, spread route, and age/aggressiveness split them.