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Papillary carcinoma
- Predominant form
- Palpable lymph nodes (lymphatic metastasis is common)
- Positive I¹³¹ uptake
- Positive prognosis
- Pops out of capsule (invades capsule)
- Post-radiation in head and neck, Post-thyroiditis, Polyposis (FAP)
- Pops everywhere in the gland (multifocal in 20%)
- Histology: Papillary projections, Pale empty (Orpha annie eye) nuclei, Psammoma bodies, Pseudoinclusions
Follicular carcinoma
- Fifties females
- Far-away metastasis (hematogenous)
- Favorable prognosis
- Forever alone (solitary nodule)
- Filled inside capsule (encapsulated macroscopically but invasion seen microscopically – distinguishing feature from follicular adenoma)
- FNAC futile (cannot distinguish between follicular adenoma and carcinoma)
- Frozen (cold radionuclide scan)
- Follicular pattern
Medullary carcinoma
Mnemonic: MENACED
- MEN 2A and 2B association (RET gene mutation)
- Multimodal metastases (lymphatic and hematogenous)
- Amyloid deposition
- C-cells origin; Calcitonin positive
- Endocrine tumor (neuroendocrine tumor)
- Diarrhea and flushing are classic
Anaplastic carcinoma
- Aggressive
- Aged females
- Anaplastic transformation of differentiated thyroid carcinoma
- All over (local invasion + lymphatic + hematogenous metastasis)