Second Primary Differentiated Thyroid Carcinoma in Adult Cancer Survivors: A SEER Database Analysis

CONTEXT

Adult cancer survivors are at a heightened risk for secondary primary differentiated thyroid carcinoma (2-DTC). The characteristics and outcomes of 2-DTC remain poorly understood.

OBJECTIVE

We aimed to explore the characteristics and outcomes of 2-DTC.

METHODS

We retrospectively analyzed data from the Surveillance, Epidemiology, and End Results (SEER) database (2000-2017). 2-DTC was divided into 25 subgroups based on prior primary malignancies (PPMs). Baseline characteristics were compared using the chi-square test. Multivariable logistic analysis was used to identified if PPMs were associated with aggressive DTC characteristics. DTC-specific and cancer-specific mortality were analyzed using a univariable and multivariable competing risk regression model.

RESULTS

There were 138 555 1-DTC and 9253 2-DTC patients identified. 2-DTC patients were predominantly older, male, and White compared to first primary DTC (1-DTC) (all P < .05). In multivariable logistic regression analysis, only 4 types of PPMs were associated with higher rates of DTC aggressive characteristics, while 19 types exhibited lower rates (all P < .05). In multivariable competing risk analysis, 2-DTC showed no mortality risk in stages I (SHR: 1.16; 95% CI, 0.65-2.07) and II (SHR: 0.67; 95% CI, 0.45-1.01), but a protective role in stages III (SHR: 0.47; 95% CI, 0.27-0.83) and IV (SHR: 0.72; 95% CI, 0.52-0.99). Most PPMs that developed into 2-DTC had a lower risk of DTC-specific death than 1-DTC, but many PPMs had a higher risk of cancer-specific death.

CONCLUSION

Given the characteristics and outcomes of 2-DTC, aggressive treatment for 2-DTC, particularly for PPM with a high mortality risk, may not be advisable.

2022 European Thyroid Association Guidelines for the management of pediatric thyroid nodules and differentiated thyroid carcinoma

At present, no European recommendations for the management of pediatric thyroid nodules and differentiated thyroid carcinoma (DTC) exist. Differences in clinical, molecular, and pathological characteristics between pediatric and adult DTC emphasize the need for specific recommendations for the pediatric population. An expert panel was instituted by the executive committee of the European Thyroid Association including an international community of experts from a variety of disciplines including pediatric and adult endocrinology, pathology, endocrine surgery, nuclear medicine, clinical genetics, and oncology. The 2015 American Thyroid Association Pediatric Guideline was used as framework for the present guideline. Areas of discordance were identified, and clinical questions were formulated. The expert panel members discussed the evidence and formulated recommendations based on the latest evidence and expert opinion. Children with a thyroid nodule or DTC require expert care in an experienced center. The present guideline provides guidance for healthcare professionals to make well-considered decisions together with patients and parents regarding diagnosis, treatment, and follow-up of pediatric thyroid nodules and DTC.

The Controversy of Lateral Aberrant Thyroid and the use of BRAF Immunostain

A 29-year-old women presents with primary intrathyroidal papillary thyroid carcinoma (BRAF VE1 positive) with morphologically recognizable metastases to cervical lymph nodes (BRAF VE1 positive) as well as a focus of bland-appearing thyroid follicles within the capsule of a level II lymph node (BRAF VE1 negative). There exist various theories regarding the possible developmental origins of "benign" intranodal thyroid tissue in the lateral neck. While the true nature of the bland follicles may not be definitively resolved in this case, these findings are suggestive that they do not represent metastasis from the main papillary thyroid carcinoma. Additional insight into this unusual phenomenon may be gathered by more specific clonal analysis of these microscopic foci.

Incidental cervical lymph node metastasis of papillary thyroid cancer in neck dissection specimens from a tongue squamous cell carcinoma patient: a case report

We report a rare case of lymph node metastasis of papillary thyroid cancer (PTC) incidentally detected in a neck dissection specimen of tongue squamous cell carcinoma (SCC). A 42-year-old Japanese woman was diagnosed with tongue SCC (T1N0M0, Stage I). Partial glossectomy with supraomohyoid neck dissection was performed under general anesthesia, and histopathological examinations revealed primary SCC of the tongue and neck metastasis of PTC in neck dissection specimens. A few months later, total thyroidectomy and left modified radical neck dissection were performed by thyroid surgeons. The histopathological diagnosis was PTC of both the thyroid glands. There was no evidence of tumor recurrence or distant metastasis at the 9-month follow-up.

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.