A 35-year old female presented with a swelling in the neck for the past 2 months, she had the treatment for Hodgkin’s lymphoma when she was 22 years with irradiation. On examination, her vitals were normal, there was a single, firm, irregular nodule, moving with deglutition in the left side of midline. Clinical examination also revealed a single node in the left side of the neck. The most likely clinical diagnosis of this condition is:
Papillary Carcinoma of Thyroid:

Accounts for 80% of all thyroid malignancies in iodine-sufficient areas.
MC thyroid cancer in children and individuals exposed to external radiation.
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 changes.
Multifocality is common (up to 85% of cases) on microscopic examination.
Multifocality is associated with an increased risk of cervical nodal metastases.
Rarely invade adjacent structures such as the trachea, esophagus, and RLN.
Rarely encapsulated (PCT are seldom encapsulated).
Other variants: Tall cell, insular, columnar, diffuse sclerosing, clear cell, trabecular, and poorly differentiated types; account for about 1%; associated with a worse prognosis.

Histological characteristics of Papillary Carcinoma Thyroid:

Papillary projections: PTC contains branching papillae of cuboidal epithelial cells
Orphan Annie eyed nuclei: The nuclei contain finely dispersed chromatin, which imparts an optically clear or empty appearance, giving rise to term ground glass or Orphan Annie eyed nuclei.
Invaginations of cytoplasm in cross-sections: Intranuclear inclusions (pseudo-inclusion) or intranuclear grooves.
Diagnosis of PTC is based on these nuclear characteristics even in the absence of papillary structures.
Psammoma bodies: Microscopic, calcified deposits representing clumps of sloughed cells.

Clinical Features:

Most patients are euthyroid and present with a slow-growing painless mass in the neck.
Dysphagia, dyspnea and dysphonia are associated with locally advanced invasive disease.
Lymph node metastases are common, 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 cancer.
Distant metastases are uncommon at initial presentation, but may ultimately develop in up to 20% of patients.
The MC sites of metastasis: Lungs >bone >liver >brain.

Diagnosis:

Diagnosis is established by FNAC of the thyroid mass or lymph node.
Once thyroid cancer is diagnosed on FNAC, a complete neck ultrasound to evaluate the contralateral lobe and for LN metastases in the central and lateral neck compartments.

Treatment: Total or near-total thyroidectomy

During thyroidectomy, enlarged central neck nodes should be removed.
Biopsy-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 rate
Recurrence of lymphoma
Malignant goiter
Benign multinodular goiter
Toxic nodular goiter