Histopathologic and immunohistochemical characterization of a primary papillary thyroid carcinoma in the lateral cervical lymph node

Heterotopic squamous epithelial inclusion cyst in a cervical lymph node in a child: a case report and literature review

BACKGROUND

A squamous epithelial inclusion cyst in a lymph node is a rare heterotopic phenomenon. Heterotopic squamous inclusion cysts in cervical lymph nodes are even rarer, and to date, only 3 such cases have been reported in the literature, none of which have described the ultrasound features. Here, we report a pediatric case, focusing on the ultrasonographic manifestations of the disease and the differential diagnosis of cervical space-occupying lesions in children.

CASE DESCRIPTION

We report the case of a 6-year-old boy in good health, who presented with a non-tender mass on the right side of the neck 1 month earlier. Some 7 days before admission, the mass gradually increased in size and became tender. Laboratory tests showed an increase in C-reactive protein of 17 mg/L (normal range: 0-8 mg/L). The physical examination revealed a palpable 3.0 cm × 2.0 cm mass with tenderness and poor mobility in the right submandibular region. Doppler ultrasonography showed an oval, ill-defined mass in the right submandibular area, consisting of a peripheral homogeneous hypoechoic component with hilar-like vascularity and an internal heterogeneous very hypoechoic component with patchy hyperechoic areas. The computed tomography (CT) scan showed a heterogeneously hypodense mass with irregular annular enhancement in the right submandibular region. Lymph node tuberculosis or space-occupying lesions were suspected based on the clinical and imaging findings. The mass was completely excised by surgery. The pathological diagnosis was a secondary infection of squamous epithelial inclusion cysts in the right cervical lymph node. The peripheral homogeneous hypoechoic component was normal lymph node tissue, and the internal heterogeneous very hypoechoic component was a squamous inclusion cyst with keratin debris. The patient was followed up for a total of 3 times after surgery, and no recurrence of the tumor was found.

CONCLUSIONS

Ultrasonography can help in the early diagnosis of heterotopic squamous inclusion cysts in children's cervical lymph nodes, and can be used to differentiate other cervical lesions. We reviewed the literature and found that this heterotopic phenomenon was more likely to occur in the submandibular region of the neck in younger patients. Surgery may be an effective treatment for this disease.

Thyroid tissue outside the thyroid gland: Differential diagnosis and associated diagnostic challenges

The presence of thyroid tissue outside of the thyroid gland may occur in various clinical settings and anatomic locations and includes both benign and malignant differential diagnoses. Some of these entities include thyroglossal duct cyst, lingual thyroid, parasitic nodule, thyroid tissue within a lymph node and struma ovarii. In routine daily practice, these entities do pose diagnostic challenges for the pathologists. Differential diagnostic considerations depend largely on the location of lesion and the histologic features. A definitive diagnosis may remain unclear in some cases while knowledge is still evolving in others i.e., incidentally detected bland appearing thyroid follicles in a lateral neck lymph node. This article aims to elaborate on the various entities characterized by thyroid tissue outside of the thyroid gland, both benign and malignant, and the relevant differential diagnostic considerations.

Incidental findings of thyroid tissue in cervical lymph nodes: old controversy not yet resolved?

The clinical significance of papillary or follicular thyroid tissue incidentally discovered in cervical lymph nodes during pathological assessment of neck dissections for non-thyroid cancers of the upper aero-digestive tract is critically reviewed. Special emphasis is given to controversies over normal-looking, nodal, thyroid follicles. Arguments for and against the benign nature of these follicles are considered together with processes that could be involved in their formation. The admittedly limited evidence suggests that benign, thyroid follicular inclusions rarely occur in cervical lymph nodes. Histological criteria that could be helpful in recognizing the inclusions, which include assessing their extent in conjunction with the size of the node, are discussed. Finally, an algorithm based on collaboration between specialists, correlating histological findings with imaging and loco-regional control of the upper aero-digestive tract cancer, is suggested for the management of patients with incidentally discovered, nodal thyroid tissue.

High expression of claudin-1 protein in papillary thyroid tumor and its regional lymph node metastasis

Claudins, known as major contributors in the formation of the tight junction, are differentially expressed in malignant tumors as compared to the corresponding healthy tissues. Therefore, they are thought to play a role in carcinogenesis and tumor progression. Altered expression of claudin-1 has been reported in several tumor types including endometrial, papillary renal cell and colonic carcinoma, and increased claudin-1 mRNA levels have been observed in papillary thyroid carcinoma (PTC). In this study, we aimed at determining the pattern of claudin-1 expression in various types of thyroid lesions at the protein level and investigating the immunolocalization of beta-catenin reported to regulate claudin-1 expression. Samples included 19 PTCs, ten cases of corresponding regional lymph node metastasis, eight papillary microcarcinomas (PMC), 17 follicular thyroid carcinomas (FTC) and 19 follicular adenomas (FA). All cases were evaluated by quantitative immunohistochemistry. Conspicuous claudin-1 immunostaining was detected in the majority of PTC/PMC primary tumors and lymph node metastases (19/27 and 9/10, respectively). On the other hand, we found weak or no claudin-1 expression in any of the FA and FTC cases or peritumoral non-malignant thyroid tissues. Our data prove that high claudin-1 protein expression is specific for PTC and its regional lymph node metastases, while we failed to verify that claudin-1 is regulated by beta-catenin in thyroid tumors. Based on these results, claudin-1 may be a useful tumor marker for PTC.