Description 

A 28-year-old Caucasian man was referred to the head and neck clinic with a 2-year history of a right-sided neck lump, which had started to cause discomfort. Physical examination revealed two discrete non-tender neck masses in the region of the right sternocleidomastoid muscle, with no bruit or palpable pulse.

CT demonstrated multiple right-sided thin-walled cystic lesions within the upper to lower jugular chain and posterior triangle (levels II–V) forming a multiloculated cystic lesion measuring 10 cm in craniocaudal dimension. Ultrasound assessment suggested a multiloculated cystic mass with thin walls and no intralesional flow, extending along the posterior margin of the right sternocleidomastoid muscle, posterolateral to the right internal jugular vein. The thyroid and major salivary glands appeared unremarkable. Fine-needle aspiration cytology (FNAC) proved inconclusive. The abnormality was presumed to be a slow-flow lymphatic malformation; however, injection sclerotherapy did not result in resolution, confirmed on an MRI scan performed 6 months later (figure 1). FNAC was not repeated due to the working diagnosis. Following multidisciplinary team discussion, a comprehensive selective right-sided neck dissection of levels II–V was performed using a low lateral skin crease incision at the level of the cricoid cartilage yielding 15 markedly cystic lymph nodes. All anatomical structures were identified and preserved. The neck masses were found to be cystic and dark in colour intraoperatively (figure 2). Histological analysis revealed the nodes to be positive for thyroid transcription factor 1, indicative of papillary thyroid cancer (PTC) metastases. The patient underwent total thyroidectomy extending the same incision to the anterior neck, which demonstrated microscopic PTC. As the neck dissection was complete, there was no need to reopen the lateral neck. Radio-iodine ablation treatment was then administered. The patient remains disease free at 6 months’ clinical and biochemical follow-up.

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Figure 1

T2 fat-saturated MRI study of the neck that demonstrates persistence of the right-sided cystic lesion despite injection sclerotherapy. There is subtle low signal at the base of the lesion, which was initially thought to be debris. In retrospect, this is likely to reflect mural nodularity of one of the cysts.

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Figure 2

Intraoperatively, the mass was found to be cystic and dark in colour.

A cystic lateral neck mass can be a diagnostic challenge for radiologists and ear, nose and throat surgeons. Differential diagnoses include a metastatic node, branchial cleft cyst, lymphovascular malformation, necrotic node post-suppurative lymphadenitis and cystic neurogenic tumour. In adults, cystic metastatic nodes from head and neck cancer are well recognised, especially from squamous cell carcinoma and papillary carcinoma. The presence of a thickened wall and/or mural nodularity in a cystic mass should raise the possibility of malignancy, although this cannot be relied on, as metastatic nodes can be thin walled and completely cystic.1 Therefore, any cystic neck mass in the lateral neck in an adult should undergo US-guided FNAC for confirmation. Unfortunately in this case, the FNAC was inconclusive. That there were multiple cystic nodes was not appreciated before surgery as the nodes were abutting one another, simulating a multiloculated cystic lesion.

Patients with PTC usually present with a palpable or incidentally detected impalpable thyroid nodule; however, they may present with cervical lymphadenopathy.2 3 Rarely, the primary tumour may be microscopic and radiologically occult. Definitive treatment for PTC with nodal metastasis comprises total thyroidectomy with selective neck dissection and radioactive iodine, followed by long-term hormonal suppression. PTC has an excellent prognosis with over 90% 5-year survival for early stage disease.