Papillary thyroid microcarcinoma presenting as lymph node metastasis – a diagnostic challenge: case report and systematic review of literature

Abstract

Papillary thyroid microcarcinomas (PTMcs) have an excellent prognosis, although a few may metastasize to cervical lymph nodes. However, an infiltrated palpable neck node without evidence of thyroid disease at presentation is uncommon. We report a patient with PTMc presenting as a solitary lymph node metastasis without evidence of primary thyroid tumor in thyroid imaging and with inconclusive lymph node fine-needle biopsy (FNB) cytology. In our case, node excision and histological examination set the diagnosis and immunocytochemical staining of the FNB specimens verified it. A systematic review of reported similar cases was performed; relevant diagnostic dilemmas were also summarized. The clinical presentation of this type of papillary carcinoma becomes evident at a relatively younger age and affects almost equally the two genders; the enlarged lymph node is almost exclusively ipsilateral to the primary tumor, which may be unifocal or multifocal and is difficult to detect by thyroid imaging modalities. Lymph node FNB cytology, thyroglobulin (Tg) measurement in the washout liquid of the FNB needle, FNB immunocytochemistry and lymph node excision accompanied by histological examination provide a stepwise diagnostic approach. We conclude that PTMc may present as a lymph node metastasis without evidence of a primary thyroid tumor. In such cases, thyroid malignancy should be suspected and, in the presence of negative or non-diagnostic lymph node FNB cytology, measurement of Tg in the fluid aspirate should be performed.

Acoustic Radiation Force Impulse Imaging: A New Tool for the Diagnosis of Papillary Thyroid Microcarcinoma

“…PTMC had been considered as a “silent” cancer because most cases followed an indolent course with an excellent prognosis compared to the thyroid carcinoma > 1 cm [13]. Thyroid microcarcinoma is almost always of the papillary histotype and becomes evident at a relatively younger age and affects almost equally the two genders [14], as had also been demonstrated in this study. But high rate of multicentricity (32%–39.2%), bilaterality (20%–22.3%), invasiveness (18%–25%), lymph node metastases (16%–44.6%), and distant metastases (3%–7%) were reported in several series in nonincidental mPTC [15–17].…”

Thyroid Carcinoma on the Side of the Absent Lobe in a Patient with Thyroid Hemiagenesis

“…An extremely small primary lesion could have been present within thyroid tissue in the right lobe, with further lymph node metastasis to the site of the absent gland on the left resulting in the lesion. Multiple reports have described thyroid microcancer and lymph node metastasis to date, as reviewed by Anastasilakis et al [ 19 ] Even a primary as small as 2 mm can lead to cervical lymph node metastasis. In our case, pathological examination of the residual thyroid using 5 mm thick slices found no microcancer.…”

Papillary thyroid microcarcinoma with synchronous asymptomatic advanced esophageal squamous cell carcinoma: A case report and review of the literature

“…The use of thyroid US and US-guided fine-needle aspiration biopsy (FNAB) has made it easier to detect PTMC. Although PTMC is always benign itself, thus, resulting in a favorable clinical outcome, cases accompanied by regional lymph node and distant metastasis have been well documented in the literature ( 11 – 13 ). In the current patient, PTMC was considered to be the most likely diagnosis, based on the imaging features of asymptomatic nodules identified by US and the enlarged lymph nodes identified by palpation of the left neck.…”