Lymphatic spread is most commonly seen in which type of thyroid malignancy:

Ans. a. Papillary carcinoma (Ref: Robbins 9/1096, 8/1121-1122, Schwartz 9/1361-1363: Sabiston 19/906-909; Bailey 26/765-768, 25/793-796; Harrison 18/2936)Papillary Carcinoma of ThyroidAccounts for 80% of all thyroid malignancies in iodine-sufficient areasQMC thyroid cancer in children and individuals exposed to external radiationQ.More often in women, 30-40 years.Pathology:Grossly: Hard and whitish and remain flat on sectioning with a blade with macroscopic calcification, necrosis, or cystic changesMultifocalityQ is common (up to 85% of cases) on microscopic examination.Multifocality is associated with an increased risk of cervical nodal metastasesQ, rarely invade adjacent structures such as the trachea, esophagus, and RLNs.Rarely encapsulatedQ (PCT are seldom encapsulated)Other variants: Tall cellQ, insularQ, columnar, diffuse sclerosing, clear cell, trabecular, and poorly differentiated types: account for about 1%; associated with a worse prognosis.Histological characteristics of Papillary Carcinoma ThyroidPapillary projectionsQ: PTC contains branching papillae of cuboidal epithelial cellsOrphan Annie eye nuclei:The nuclei contain finely dispersed chromatin, which imparts an optically clear or empty appearance, giving rise to term ground glass or Orphan Annie eye nucleiQInvaginations of cytoplasm in cross-sections: Intranuclear inclusionsQ (pseudoinclusion) or intranuclear groovesQ.Diagnosis of PTC is based on these nuclear characteristicsQ even in the absence of papillary structures.Psammoma bodiesQ: Microscopic, calcified deposits representing dumps of sloughed cellsClinical Features:Most patients are euthyroid and present with a slow-growing painless massQ in the neck.Dysphagia, dyspnea & dysphonia are associated with locally advanced invasive disease.Lymph node metastases are commonQ, especially in children and young adults, and may be the presenting complaint."Lateral aberrant thyroid" almost always denotes a cervical lymph node that has been invaded by metastatic cancerQ.Distant metastases are uncommon at initial presentation, but may ultimately develop in up to 20% of patients.The MC sites of metastasis: LungsQ >bone >liver >brain.Diagnosis:Diagnosis is established by FNAC of the thyroid mass or lymph nodeQ.Once thyroid cancer is diagnosed on FNAC, a complete neck ultrasound to evaluate the contralateral lobe and for LN metastases in the central & lateral neck compartments.Treatment: Total or near-total thyroidectomyQDuring thyroidectomy, enlarged central neck nodes should be removedQBiopsy-proven lymph node metastases detected clinically or by imaging in the lateral neck in patients with papillary- carcinoma are managed with modified radical neck dissection.Prognosis:PTC have an excellent prognosis with a >95% 10-year survival rateQ.