Orris

take only Cummings as reference and explain in detail about management of papillary thyroid carcinoma and follicular thyroid carcinoma

Reading File
Finding Sources
Finding Sources
Finding Sources
Finding Sources
Finding Sources
Finding Sources
Finding Sources
Finding Sources
Reading File
Reading File
Finding Sources
Finding Sources
Reading File
Reading File
Reading File
Reading File
Reading File
Reading File
Reading File
Reading File
Reading File
Reading File
Reading File
I now have comprehensive content from Cummings. Let me also get the radioiodine/TSH suppression/staging sections, which I partially read earlier. I have enough information to write a detailed, well-organized answer. Let me compile it now.

Management of Papillary Thyroid Carcinoma (PTC) and Follicular Thyroid Carcinoma (FTC)

Based exclusively on Cummings Otolaryngology Head and Neck Surgery

PAPILLARY THYROID CARCINOMA (PTC)

Epidemiology and Clinical Presentation

PTC is the most common thyroid malignancy, accounting for about 80% of all thyroid cancers. It typically occurs in patients aged 30-40 years and is more common in women (female:male ratio of 2:1, though this ratio has been decreasing). It is the predominant thyroid malignancy in children (75%). Most cases occur spontaneously; however, a history of low-dose radiation exposure results in papillary carcinoma in 85-90% of radiation-induced thyroid malignancies. Associated syndromes include Cowden syndrome, Gardner syndrome, and familial polyposis.
Most patients present with a slow-growing, painless neck mass and are euthyroid. Thirty percent may have clinically evident cervical nodal disease at presentation. Advanced disease may cause dysphagia, dyspnea, or hoarseness from local invasion. Distant metastases occur in fewer than 5% of all patients (more common in children), most frequently to the lungs.
  • Cummings Otolaryngology, pp. 2378-2380

Pathology

On gross examination, PTC is firm, white, and non-encapsulated. Histologically, it arises from follicular cells and contains papillary structures with a neoplastic epithelium overlying a true fibrovascular stalk. Key histologic features include:
  • Orphan Annie eye nuclei - large, crowded nuclei with folded and grooved nuclear margins and intranuclear cytoplasmic inclusions
  • Psammoma bodies - laminated calcium densities present in 40% of cases, likely remnants of necrotic calcified cells
  • Pale abundant cytoplasm, cuboidal cells
The designation of PTC includes mixed papillary-follicular carcinoma and the follicular variant of PTC. Both behave clinically as papillary carcinoma (except for NIFTP). More unfavorable prognoses are associated with:
  • Tall cell variant - cells twice as tall as wide with well-formed papillae
  • Diffuse sclerosing variant
  • Columnar cell variant - prominent nuclear stratification
PTC has a strong tendency for lymphatic spread within the thyroid and to paratracheal and cervical nodes. Microscopic disease is found in cervical nodes in 50-80% of patients and in the contralateral lobe in 80% at surgery. Despite this, clinical recurrences in the neck and contralateral lobe occur in fewer than 10%, reflecting the indolent nature of most PTC.
  • Cummings Otolaryngology, pp. 2379-2380

Diagnosis

  • FNAC is the procedure of choice for evaluation. Accuracy for PTC diagnosis is 99% with a very low false-negative rate
  • Thyroid function tests (TSH) are done routinely preoperatively
  • CT with iodinated contrast should be avoided in suspected PTC or FTC, as it may negatively impact the initiation of radioactive iodine (RAI) therapy
  • CT/MRI are selectively used for extensive local or substernal disease and lymph node evaluation
  • Ultrasonographic features concerning for malignancy: size >4 cm, microcalcifications, irregular or infiltrative margins, hypoechogenicity, subcapsular localization, increased intranodular vascularity, and enlarged regional lymph nodes
  • Cummings Otolaryngology, pp. 2375, 2378

Staging

The AJCC 8th Edition TNM staging is currently used:
  • Microscopic extrathyroidal extension does NOT factor into the T category
  • Gross extrathyroidal extension to the strap musculature = T3b
  • Studies show microscopic extrathyroidal extension did not worsen disease-free survival, locoregional failure, or distant metastatic failure
  • Papillary microcarcinoma = tumor ≤1.0 cm (typically nonpalpable, often incidental)
Risk Factors for Aggressive Behavior (Box 122.2):
CategoryRisk Factors
DemographicsAge <20 years; Men or women >55 years; Male sex; Radiation history; Family history
PhysicalHard/fixed lesion; Rapid growth; Pain; Lymphadenopathy; Vocal cord paralysis; Airway compromise
HistopathologicSize >4 cm; Extrathyroid spread; Vascular invasion; LN or distant metastasis; Tall cell/follicular/Hurthle cell variants
  • Cummings Otolaryngology, p. 2370

Surgical Management of PTC

Extent of Surgery:
  1. Incidental micropapillary PTC (found incidentally in thyroid specimen removed for other reasons):
    • Unilateral thyroid lobectomy and isthmectomy is usually sufficient
    • Exception: if angioinvasion or tumor at margins - requires more extensive resection
    • These patients are treated with TSH suppression and followed with US
  2. Small, encapsulated PTC (<1 cm):
    • Thyroid lobectomy is sufficient
  3. Biopsy-proven bilateral disease or high-risk PTC:
    • Total thyroidectomy is the procedure of choice
    • Enables TSH suppression therapy and radioiodine ablation of residual microscopic disease
    • Also appropriate for patients with high-risk classification, to allow paratracheal lymph node dissection
Multifocal disease is present in 80% of patients in some reports, and local recurrence rates are higher with incomplete surgery.
  • Cummings Otolaryngology, p. 2379

Lymph Node Management in PTC

  1. Central compartment (Level VI) neck dissection:
    • Recommended for ultrasonographically apparent central nodal disease or gross nodal disease at surgery (per ATA guidelines)
    • Prophylactic (elective) central LND may be considered for advanced primary tumors (T3/T4) or clinically involved lateral neck nodes, though its influence on outcome remains unclear
    • The concept of "number needed to treat" vs. "number needed to harm" should guide individual surgeons
  2. Lateral neck disease:
    • Palpable/visible neck disease warrants comprehensive neck dissection (Levels II through Vb)
    • "Berry-picking" (selective excision) is NOT appropriate - formal modified radical or selective neck dissection is required
    • Level Vb is commonly involved - can be removed from under the SCM contiguous with Level IV nodes
    • Level I is seldom involved
    • Elective treatment of contralateral neck is NOT advocated (contralateral subclinical metastasis <20%)
  3. Lymph node micrometastases (<1 cm) typically have no impact on survival but may increase locoregional recurrence risk
  4. Lymph node density (positive/total nodes): density ≤0.19 = 98% 10-year disease-specific survival; density >0.19 = 90% survival
  • Cummings Otolaryngology, p. 2380

Radioiodine (RAI) Therapy in PTC

After total thyroidectomy, radioiodine (131I) can ablate residual thyroid tissue and micrometastatic disease. Indications per ATA and current recommendations:
  • Distant metastases
  • Large tumors (T3 or greater)
  • Extensive regional nodal involvement
  • For pediatric patients: RAI indicated for distant metastases, large tumors, or extensive nodal disease
Low-risk patients with no/low identified thyroid remnant and low or undetectable stimulated thyroglobulin may safely avoid RAI.
Risks (dose-dependent): xerostomia, pulmonary fibrosis, menstruation abnormalities, decreased sperm count, secondary malignancies including leukemia.
  • Cummings Otolaryngology, p. 3858

TSH Suppression Therapy in PTC

After total thyroidectomy, thyroid hormone (T4) is administered to keep TSH suppressed, which reduces stimulation of any residual thyroid tissue. Thyroglobulin (Tg) levels should be undetectable following ablative therapy and serve as the primary tumor marker for surveillance.
  • Cummings Otolaryngology, p. 3858

Postoperative Surveillance

  • Thyroglobulin (Tg) levels - should remain undetectable; rising Tg raises suspicion for recurrence
  • Neck US - periodic evaluation of central and lateral cervical compartments
  • Postoperative imaging for abnormal thyroglobulin or masses concerning for recurrence
  • Follow ATA guidelines (continually updated)

Prognosis of PTC

  • 5-year survival rate: >95% (even in children with advanced disease)
  • ~12% of patients are not cured by initial treatment
  • Recurrent disease may occur years later:
    • Thyroid bed: 5-6%
    • Regional lymphatics: 8-9%
    • Distant sites: 4-11%
  • Cervical recurrences occur in 20% of low-risk and 59% of high-risk patients
  • Salvage surgery for recurrence yields excellent results: regional control rate 94%, disease-specific survival 100% at median 44 months (central neck); lateral neck: 98% regional control, 91% disease-specific survival at 10 years
  • Presence of distant metastasis = worse prognosis
  • Cummings Otolaryngology, pp. 2380

FOLLICULAR THYROID CARCINOMA (FTC)

Epidemiology and Clinical Presentation

FTC is the second most common thyroid cancer, accounting for ~10% of cases. It tends to present in slightly older patients than PTC. Patients usually present with a solitary thyroid nodule, often with a history of longstanding goiter and recent rapid growth. Lesions are typically painless; hemorrhage may cause pain. In rare cases (1%), the tumor may be hyperfunctioning with signs of thyrotoxicosis.
A key distinction from PTC: FNAC cannot differentiate follicular carcinoma from follicular adenoma - about 20% of nodules with follicular cytology on FNAC will ultimately contain carcinoma.
Unlike PTC, FTC is less likely to metastasize via lymphatics (<10% of patients). Instead, it spreads by:
  • Local extension
  • Hematogenous spread (the predominant route)
  • Common distant sites: bone (pathologic fracture may be the initial presentation), liver, lung, and brain
When cervical lymph node disease is found with apparent FTC, it often indicates significant local disease and visceral invasion, and the pathologist should be consulted because the patient may actually have a follicular variant of PTC.
  • Cummings Otolaryngology, pp. 2380-2381

Pathology

FTC tends to manifest as solitary, encapsulated lesions. Cytologic analysis reveals small follicular arrays or solid sheets of cells. The follicular structures have lumens without colloid, and the architectural pattern depends on the degree of differentiation. Increased cellularity raises suspicion for carcinoma, but cytology alone cannot distinguish benign from malignant.
Histologic criteria (permanent sections) required for diagnosis:
  • Capsular invasion
  • Vascular invasion of vessels along the tumor capsule
  • Complete capsular evaluation is mandatory
  • Frozen-section analysis is often inadequate - definitive diagnosis requires complete assessment of permanent sections
Classification by invasiveness:
CategoryFeaturesPrognosis
Minimally invasiveInvasion into (but not through) the tumor capsule at one or more sites; no small-vessel invasionExcellent - behaves like follicular adenoma
Frankly/widely invasiveInvasion through the tumor capsule + vascular invasion; may be visible in middle thyroid or jugular veins at surgerySignificantly worse; higher distant metastasis rates
Aneuploid follicular carcinomas behave more aggressively.
  • Cummings Otolaryngology, p. 2381

Surgical Management of FTC

Step 1 - Initial surgery (based on FNAC showing "follicular neoplasm"):
  1. Thyroid lobectomy with isthmectomy - the initial surgical procedure for FNAC-diagnosed follicular lesion
    • Only ~15% of patients with FNAC diagnosis of follicular lesion will ultimately have cancer
    • The pyramidal lobe (if present) should be included in the resection
    • Unilateral partial thyroid lobectomy is no longer an acceptable standard of care
    • Intraoperative frozen sections are not helpful for FTC (cannot assess capsule adequately); frozen sections are analyzed only if there is gross suspicion of metastatic central compartment lymphadenopathy
  2. Primary total thyroidectomy may be preferred in:
    • Older patients with nodule >4 cm (risk of carcinoma ~50%)
    • Family history of thyroid carcinoma
    • History of radiation to head and neck
    • Other head and neck cancers
    • Potential high-risk factors and comorbidities
Step 2 - After histologic diagnosis of FTC (post-lobectomy):
  1. Minimally invasive FTC:
    • Initial thyroid lobectomy is generally sufficient treatment
    • Excellent prognosis - recurrence rate ~1%
  2. Invasive/widely invasive FTC:
    • Completion thyroidectomy is warranted, especially in the presence of angioinvasion
    • This permits radioiodine scanning for detection and ablation of metastatic disease
    • Note: more aggressive surgery may not improve survival since invasiveness already indicates increased likelihood of distant metastasis
  3. Neck dissection:
    • Performed if cervical lymphadenopathy is present
    • Elective (prophylactic) neck dissection is NOT warranted because nodal involvement is unlikely in FTC
  • Cummings Otolaryngology, pp. 2381, 2990-2992

Radioiodine (RAI) in FTC

After total or completion thyroidectomy for invasive FTC, radioiodine scanning and ablation can be performed to detect and ablate metastatic disease. RAI is useful for FTC because the tumor cells generally retain the ability to take up iodine (unlike Hurthle cell carcinoma).

Postoperative Surveillance for FTC

  • TSH suppression with thyroid hormone
  • Thyroglobulin (Tg) monitoring - undetectable levels expected after complete ablation
  • Periodic neck US evaluation of central and lateral cervical compartments
  • 99mTc scan or 123I scan may be used to remove residual normal thyroid tissue and allow better surveillance

Prognosis of FTC

  • Overall 5-year survival: 90%, decreasing to 84% at 10 years
  • Distant metastasis reduces 5-year survival to 82%
  • Recurrence rate after initial management: ~30% (related to degree of invasiveness, not extent of initial surgery)
  • Minimally invasive: recurrence ~1%, survival similar to follicular adenoma
  • Invasive FTC: distant metastasis in 10-20%, higher than PTC
Factors worsening prognosis:
  • Age >50 years at presentation
  • Tumor size >4 cm
  • Higher tumor grade
  • Marked vascular invasion
  • Extrathyroid extension
  • Distant metastasis at diagnosis
The historically reported worse prognosis of FTC vs PTC may be partly due to older age at presentation, more advanced stage, and higher rate of distant metastases. When matched for age, sex, and stage, survival is similar. However, patients who develop locoregionally recurrent FTC have decreased overall survival (unlike PTC, where locoregional recurrences can be salvaged effectively).
  • Cummings Otolaryngology, pp. 2381, 3994-3995

Summary Comparison Table

FeaturePapillary Carcinoma (PTC)Follicular Carcinoma (FTC)
Frequency~80% of thyroid cancers~10%
Age at presentation30-40 yearsSlightly older
FNAC diagnosisCan suggest PTC (99% accuracy)Cannot distinguish from adenoma
Spread patternPredominantly lymphaticPredominantly hematogenous
Nodal metastasisCommon (50-80% microscopic)Uncommon (<10%)
Distant metastasis<5%; lungs most commonMore common; bone, liver, lung
Multifocality80%Less common (usually solitary)
Histologic diagnosisPapillary structures, Orphan Annie nuclei, psammoma bodiesRequires capsular/vascular invasion on permanent section
Initial surgeryLobectomy (low-risk) or total thyroidectomyLobectomy with isthmectomy
Completion thyroidectomyIf bilateral/high-riskIf invasive/angioinvasive on final histology
Elective neck dissectionProphylactic central may be considered (T3/T4)NOT indicated
RAIIndicated for T3+, extensive nodes, distant metsIndicated for invasive disease/distant mets
5-year survival>95%~90%
Recurrence salvageabilityExcellentDecreased survival with locoregional recurrence
All content sourced from: Cummings Otolaryngology Head and Neck Surgery, Chapter 122 (Thyroid), pp. 2370-2381, and Chapter on Pediatric Thyroid Malignancy, pp. 3857-3859.
This is a shared conversation. Sign in to Orris to start your own chat.