The Molecular Signature More Than the Site of Localization Defines the Origin of the Malignancy

Sign of Neck Mass as the Chief Complaint: A Case Report and Literature Review About Thyroid Metastasis of Colorectal Cancer

Background

Commonly, the thyroid gland is regarded as an organ with fewer metastatic diseases, and colorectal metastasis to the thyroid (CMT) is rarely reported, especially, with that the clinical sign of thyroid metastasis nidus is the chief complaint. The CMT occurs in advanced colorectal cancer and is associated with poor prognosis and short survival.

Case Report

In this case, we reported a patient with the sign of neck mass as the first manifestation of CMT. The patient underwent a partial thyroidectomy in June 2019, immunohistochemical findings of thyroid carcinoma suggested the possibility of adenocarcinoma of gastrointestinal tract. The patient underwent a colonoscopy in July 2019 and a colonic mass was found. Pathological examination diagnosed rectal adenocarcinoma. The patient underwent neoadjuvant chemotherapy, surgical treatment, postoperative adjuvant chemotherapy and targeted therapy. The patient died in June 2022.

Conclusion

The metastasis disease would not be ignored at all, when a patient complains at signs of neck mass. Further, the possibility of metastasis cancer should be considered once thyroid nodules occur in patients with colorectal cancer. Even though the biological characteristics and stage of the primary tumor have an important impact on the prognosis, positive standardized treatments can also be helpful.

A Misleading Case of NTRK-Rearranged Papillary Thyroid Carcinoma

Herein, we present a misleading case of advanced papillary thyroid carcinoma with lung, node, and pleural metastases, initially diagnosed as metastatic lung adenocarcinoma with papillary features, based on the histological and immunohistochemical analysis of a pleural biopsy. Between August 2019 and August 2020, the patient received 2 ineffective lines of systemic therapy, including a first line of chemotherapy with cisplatin and pemetrexed, and a second line of immunotherapy with atezolizumab. Comprehensive genomic profiling by next-generation sequencing on the archival pleural biopsy revealed an NTRK1-TMP3 fusion and comutation of the TERT promoter, commonly found in papillary thyroid carcinoma. After palliative partial thyroidectomy that confirmed the diagnosis of papillary thyroid carcinoma, in February 2021, the patient was enrolled in the STARTRK-2 GO40782 basket trial and received entrectinib, an oral pan-TRK inhibitor specifically targeting NTRK-rearranged tumors. After initially experiencing drug-related grade 2 anorexia, dysgeusia, and neurotoxicity and grade 3 asthenia, the dose was reduced, and an excellent and durable objective response was observed.

Core Needle Biopsy Can Early and Precisely Identify Large Thyroid Masses

Background

Large thyroid masses, particularly if rapidly growing, are often characterized by compression and infiltration of the vital structures of the neck. Therefore, an early and precise diagnosis, not only of malignancy but also of histotype, is mandatory to set up the right therapy. The aim of this study was to evaluate the diagnostic performance of fine needle aspiration cytology (FNAC) and core needle biopsy (CNB) in this setting.

Patients and Methods

We prospectively evaluated 95 patients with large and rapidly growing thyroid masses admitted to the University Hospital of Pisa between April 2014 and January 2020. All patients were submitted to FNAC and CNB in the same session. The ability of both procedures to diagnose the malignancy of the lesions, particularly the histotype, and to obtain sufficient material to perform molecular analysis was evaluated.

Results

FNAC obtained adequate tumor sample to reach a diagnosis in 76 of 95 (80%) patients, while a higher percentage was obtained with CNB (92/95, 96.8%). FNAC was able to identify the malignancy of the lesion in 74 of 95 (77.9%) cases, but only in 16 of 74 (21.6%) cases was it able to define the histotype. CNB was able to define the malignancy of the lesion in all but three cases (92/95, 96.8%), and in all specimens, the histotype was identified. Moreover, in all cases, the material extracted from CNB was optimal to perform molecular analysis. No surgery-related complications were experienced with both procedures.

Conclusions

CNB is a rapid and safe procedure with higher performance compared to FNAC in identifying the histotype of large and rapidly growing thyroid masses. Moreover, adequate material can be obtained to characterize the molecular profile for the treatment of potentially lethal cancers. In the era of precision medicine, CNB should be introduced in routine clinical practice as a key procedure for an early diagnosis and therapy of these diseases.