Curious Residents of the Thyroid Gland: Two Case Reports of Colorectal Carcinoma Metastasis by Fine-Needle Aspiration Diagnosis

Colorectal cancer metastasis to the thyroid: A case report and review of the literature

Metastatic thyroid cancer is rare. Here, the case of a patient with colon cancer that metastasized to the thyroid is described. The patient underwent radical rectal cancer surgery in August 2017 and received six cycles of chemotherapy with oxaliplatin and capecitabine postoperatively. On August 4, 2018, the patient was admitted to the hospital due to the discovery of thyroid nodules on ultrasound and carcinoembryonic antigen levels within the normal range. The biopsy from the fine needle aspiration suggested a malignant tumor. The patient underwent radical thyroid cancer surgery. Using intraoperative rapid frozen pathology, medullary carcinoma was diagnosed. Using postoperative routine pathology combined with immunohistochemistry results, thyroid metastasis from colorectal adenocarcinoma was diagnosed. After surgery, the patient regularly visited the outpatient clinic for chemotherapy with capecitabine. As of May 2023, the patient is still alive with no recurrence.

A Rare Case of Thyroid Metastasis From Colorectal Cancer: Diagnostic and Therapeutic Challenges

The incidence of thyroid metastases among patients suffering from primary colorectal cancer is rare, and only a few cases have been described in the literature. As these metastases are usually asymptomatic, they most frequently present as incidentalomas on follow-up imaging. Hereby, we present and discuss an interesting case of metastatic sigmoid adenocarcinoma of the thyroid gland, diagnosed and treated at our institution.

Metastatic Disease to a Concurrent Thyroid Neoplasm: A Case Series and Review of the Literature

BACKGROUND

Metastatic disease to the thyroid gland is uncommon but well-described. Metastatic disease to a concurrent primary thyroid neoplasm is a rare phenomenon. We sought to study patients with metastasis to the thyroid with a focus on the histopathologic and clinical features in tumor-to-tumor metastasis.

METHODS

We identified a series of patients with metastatic disease to the thyroid, with or without a concurrent primary neoplasm, through a search of the files of the Department of Pathology. All relevant slides were retrieved and reviewed, including routine HE and immunohistochemical stains. We performed a detailed English language literature search (1962-2022) and review to identify tumor-to-tumor metastasis involving the thyroid.

RESULTS

We identified 14 patients with metastasis to the thyroid over a 22-year period. Four patients exhibited papillary thyroid carcinoma, with metastatic spread of a different malignancy seeding into the thyroid cancer. We describe the histopathologic diagnostic process and findings, clinical management, and the clinical course of tumor-to-tumor metastasis in greater detail for these 4 patients.

CONCLUSION

Tumor-to-tumor metastasis to the thyroid is a rare event with unique histopathologic features. Our findings suggest that the phenomenon of tumor-to-tumor metastasis serves to highlight broader mechanisms of metastatic disease in general. We provide the largest-to-date and comprehensive review of the literature to identify all previous reported instances of tumor-to-tumor metastasis involving the thyroid.

Metastases to the Thyroid Gland: What Can We Do?

Metastases to the thyroid gland arise from other malignant tumors such as renal cell carcinoma, colorectal cancer, lung cancer, and breast cancer. In clinical practice, the incidence is low, and the symptoms are not specific, so it is often missed and misdiagnosed. It is finally diagnosed via the comprehensive application of many diagnostic methods, such as ultrasound, fine-needle aspiration biopsy, and immunohistochemistry analysis. Surgery-based comprehensive treatment is often adopted, but because it is usually in the late stage of the primary tumor, the prognosis is poor. In order to better understand the related characteristics of thyroid metastatic cancer and then improve the clinical diagnosis and treatment and the prognosis of patients, in this paper, we systematically summarize the research status of thyroid metastatic cancer.

Colorectal cancer metastases to the thyroid gland-a systematic review : Colorectal cancer thyroid metastases

BACKGROUND

Despite its rich vasculature, the thyroid gland is a rare site of metastatic disease. We present a systematic review of colorectal cancer (CRC) thyroid metastases, with emphasis on diagnosis, therapeutic management, and oncological outcomes.

METHODS

A systematic review of the English literature (1990 to 2019) was performed, using the PubMed, Embase, and Google Scholar bibliographic databases. For each patient, epidemiological, surgical, histopathological, and oncological data were extracted.

RESULTS

A total of 111 patients (40% males, mean age 61 ± 12 years) were included in the final analysis. The primary CRC was locally advanced (T3-T4) in 83%, had positive lymph nodes (N+) in 65%, and had distant metastases (M+) in 28%. Thyroid metastases were synchronous in 15% and metachronous in 80%, with a mean interval of 51 ± 31 months from primary tumor treatment. Thyroid metastatic disease was diagnosed clinically (60%), radiologically (33%), biochemically (2%), or postmortem (5%). When performed, FNA biopsy was diagnostic in 73% and highly suspicious in 13%. A total of 63% of patients had additional distant metastases, usually in the liver or lungs, while 68% of patients underwent surgical excision (total or subtotal thyroidectomy 58%, lobectomy 42%) and 43% received adjuvant chemotherapy or radiotherapy. Mean overall survival after primary CRC was 55.5 ± 34.7 months, with mean disease-free survival of 31.3 ± 27.2 months. Following diagnosis or treatment of thyroid metastases, 1-, 2- and 3-year survival rates were 79, 66, and 60%, respectively. Mean survival following diagnosis of thyroid metastases was 11.3 months.

CONCLUSIONS

CRC thyroid metastasis is a relatively uncommon event, usually associated with locoregionally advanced tumors. Prognosis is poor, mainly due to multimetastatic disease.

Metastatic rectal cancer to papillary thyroid carcinoma: a case report and review of literature

BACKGROUND

Tumor-to-tumor metastasis is a rare event. Rectal cancer to primary thyroid neoplasm metastasis is extremely rare. Herein, we reported a case of metastatic rectal adenocarcinoma to a papillary thyroid carcinoma. The incidence and clinicopathological characteristics of metastatic colorectal cancer to a thyroid gland neoplasm were described, and the pertinent literature was reviewed.

CASE PRESENTATION

A 34-year-old female patient had curative treatment of initial rectal adenocarcinoma in 2012, and was found to have lung metastases by follow-up CT scan 3 years later. In 2018, she was found to have thyroid metastasis by imaging due to left neck pain and hoarseness. A fine-needle aspiration biopsy (FNAB) result suggested suspicious papillary thyroid carcinoma (PTC). The patient underwent a total thyroidectomy and bilateral cervical lymph nodes dissection. The histopathology of thyroidectomy specimen revealed a rectal adenocarcinoma metastatic to the thyroid concomitant with the papillary carcinoma in metastatic adenocarcinoma. The patient received levothyroxine supplementation therapy and palliative chemotherapy with irinotecan and anti-angiogenesis for the metastatic rectal adenocarcinoma. After 1 year of thyroidectomy, no newly developed lesion evidence of recurrent PTC was observed. The patient remains still alive.

CONCLUSION

The possibility of metastases should be considered in patients with a history of rectal cancer and with a thyroid lesion, particularly in those with ageing, hereditary nonpolyposis colorectal cancer (HNPCC) or long-term survival. The diagnosis should be histologically confirmed for the presence of both primary thyroid lesions and secondary thyroid neoplasms. Thyroidectomy may be a feasible treatment for symptomatic thyroid metastasis or thyroid cancer. we need to gain more available evidence from large or multi-center clinical data to help clinicians to diagnose rectal cancer to thyroid neoplasm metastases and evaluate treatment.

Colorectal cancer metastases to the thyroid gland: A case report

BACKGROUND

Secondary malignancies of the thyroid gland are a rare finding in clinical practice. In addition, colorectal metastasis to the thyroid (CMT) is even more infrequently diagnosed. The source of the primary tumor follows demographic and ethnic patterns, which reflects the most prevalent malignancies in the different populations. Colorectal cancer is one of the most common types of cancer worldwide; nevertheless, CMT is infrequently diagnosed. Most of them are identified during the follow-up of gastrointestinal primary malignancies. Due to the improvement of image techniques, oncological treatment, and follow-up, survival and consequent diagnosis of metastatic disease are more frequent. Those facts make this entity a diagnostic and therapeutic challenge, due to the lack of information and the difficulties performing clinical trials and research.

CASE SUMMARY

Here, we present a case report of a patient diagnosed with CMT of adenocarcinoma of the rectum evidenced during follow-up, 4 years after neoadjuvant chemoradiotherapy, who had subsequent curative surgical treatment of the primary tumor and inter-current lung bilateral metastases.

CONCLUSION

Thyroid metastases of extra-thyroid origin are an uncommon finding, even rarer in cases of CMT. The diagnostic process, as well as survival of oncologic patients is improving, and consequently the number of metastases to the thyroid gland is increasing.