CASE 17709 Published on 12.05.2022

Cystic lymph node metastases in papillary thyroid carcinoma as an initial manifestation

Section

Interventional radiology

Case Type

Clinical Cases

Authors

Rendon Fausto Omar, Del Valle Juan Bautista, Jaen Ana, Ducrey Gabriel

Hospital Italiano de Buenos Aires, Argentina

Patient

55 years, male

Categories
Area of Interest Head and neck, Thyroid / Parathyroids ; Imaging Technique Ultrasound
Clinical History

A 55 years old male, with unremarkable medical history, attended general consultation because of a slow-growing, painless small lump on the right side of his neck. Neck ultrasound (US) was requested and upon findings, fine needle aspiration (FNA) was performed.

Imaging Findings

Neck ultrasound with high-resolution linear probe (3.5Mhz) revealed a 15mm solitary lymph node with cystic transformation and internal septations at right-sided third cervical level (fig. 1a). Additionally, a thyroid gland sonography showed a 25mm cystic nodule on its isthmus with an eccentric solid component of approximately 10x9mm with increased doppler signal (fig. 1b). The right and left lobes were normal (not shown).

Ultrasound-guided FNA was performed on the cystic lymph node (fig 2a) and on the solid thyroid nodule (fig. 2b). A dark and viscous fluid from the lymph node and six glass-slide smears from the thyroid were obtained. Cytology report concluded thyroid papillary carcinoma and cystic lymph node metastases.

Outcome and follow up:

Thyroidectomy and modified radical neck dissection (type III) was performed as initial surgical treatment (fig. 3). Postoperative radioiodine ablation was ordered. and complemented with thyroid hormone replacement therapy. The patient’s follow up was uneventful.

Discussion

Papillary thyroid carcinoma is the most frequent thyroid malignancy, and local lymph node metastases in early stages is common. In up to 20% of all cases, metastatic lymphadenopathy might be the initial manifestation of the disease [1]. The frequency of lymph node metastases is as high as 70% in lymph nodes with cystic transformation. Distant metastases are found in only 1% of patients, the two most common sites are the lung and bone, and this is an indicator of a poor prognosis [2]. Other ultrasound findings highly suggestive of malignant transformation include presence of  punctate microcalcifications, loss of echogenic fatty hilum, hyperechogenicity, round shape and abnormal vascularity. Moreover, punctate microcalcifications and cystic degeneration show a specificity and positive predictive value of 100% for malignancy, as these characteristics are not present in normal or reactive lymph nodes. Ultrasound cystic transformation features are multiple peripheral cystic areas or total replacement of the node, as well as small solitary cystic formations [3].

Ultrasound is the imaging method of choice to assess cervical lymph nodes, furthermore it provides real time guidance for FNA [3],[4]. Metastatic lymph nodes cystic fluid have high levels of thyroglobulin, therefore, fluid aspiration should also be sent for thyroglobulin analysis since there is a higher incidence of false-negative results on cytology for cystic nodes [3,5]. Efforts should be made to sample the walls and solid parts of the cyst to increase FNA cytology sensitivity, and include thyroglobulin analysis if the origin of a cystic mass in the neck is unclear or in question. Muller et al., reported a false negative rate of 45% in cytology for cystic papillary thyroid carcinoma and stated that this finding might be related to a sampling error (not targeting the solid component) rather than a cytologic misdiagnosis [6].

Outcome of the patient:

Teaching points: whenever a cystic lesion in the neck is found, thyroid scan should be performed. If percutaneous biopsy is performed, efforts should be made to sample solid components of the cyst to avoid false-negative results. Thyroglobulin analysis is an ancillary study that increases sensitivity and specificity for papillary thyroid carcinoma metastasis.

Differential Diagnosis List
Thyroid papillary carcinoma with cervical cystic lymph node metastases
Branchial cleft cyst
Lymphangioma
Lymphadenitis
Oropharyngeal squamous cell carcinoma metastases
Final Diagnosis
Thyroid papillary carcinoma with cervical cystic lymph node metastases
Case information
URL: https://www.eurorad.org/case/17709
DOI: 10.35100/eurorad/case.17709
ISSN: 1563-4086
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