Colonic adenocarcinoma metastatic to the thyroid gland: a case report with immunohistochemical investigation

Solitary thyroid gland metastasis from rectal cancer: A case report and review of the literature

BACKGROUND

Metastatic carcinoma of the thyroid gland is a rare encounter in clinical practice, but autopsy series showed that it is not so rare. Thyroid metastasis from colorectal cancer (CRC) is rare and has a poor prognosis. We herein report a rare case of solitary thyroid metastasis from rectal cancer combined with needle tract implantation after fine-needle aspiration (FNA) of the thyroid nodule and review the relevant literature.

CASE SUMMARY

A 54-year-old woman with a history of TNM stage III CRC presented a 1.3 cm × 1.0 cm mass in the left thyroid gland. FNA and histological examination of the left thyroid lobe surgical specimen confirmed the diagnosis of isolated metastatic adenocarcinoma from the rectum. Needle tract implantation was observed in the neck 11 mo after the FNA examination. The 2.5-cm seeding lesion was successfully removed by surgery, and the patient recovered well. The literature relevant to this clinical condition, the diagnostic workup, spread pathway, and surgical management of these rare lesions is reviewed.

CONCLUSION

For a patient with a thyroid mass and a history of CRC, metastatic thyroid carcinoma should be considered even if the patient has no evidence of other organ metastasis from CRC. FNA cytological examination of the thyroid mass is useful in the differential diagnosis between primary thyroid disease and metastatic thyroid carcinoma. Thyroid lobectomy of the gland containing the metastatic tumor is suggested in patients with metastatic carcinoma of the thyroid.

Prevalencia de tumores metastásicos en la glándula tiroides. Revisión sistemática y metanálisis

Introducción y objetivo: Los tumores metastásicos en la glándula tiroides complican el diagnóstico, el tratamiento y el pronóstico del paciente. El objetivo es conocer la prevalencia de las metástasis en la glándula tiroides referida en la literatura médica y los tumores primarios que con más frecuencia metastatizan en la glándula tiroides. Método: Se realizó una revisión bibliográfica sistemática en las bases de datos de PubMed, La Biblioteca Cochrane y Scopus. Los artículos seleccionados se dividieron en dos grupos, series clínicas de pacientes en los que se hallaron metástasis en tiroides (grupo A) y series de hallazgos de metástasis en tiroides en autopsias (grupo B). Se realizó metanálisis de prevalencia para cada grupo de artículos siguiendo el modelo de efectos aleatorios. Resultados: La prevalencia en cada grupo con su índice de confianza al 95% fue 0.00479 (0.002-0.007) para el grupo A y 0.0362 (0.014-0.059) para el grupo B. La prevalencia de metástasis halladas en autopsias fue 7,58 veces mayor que en los estudios clínicos. En el grupo A la edad media fue 60.82 y en el grupo B 57.20. En ambos grupos las metástasis halladas en tiroides fueron más frecuentes en el sexo femenino. La localización del tumor primario fue diferente en ambos grupos, en el grupo A fue el cáncer de riñón y en el grupo B el cáncer de mama. La variabilidad de la prevalencia de metástasis en tiroides en los diferentes artículos de ambos grupos hace que este estudio tuviese una alta heterogeneidad (índice I2 y Q). Los funnel plot de ambos grupos indicaron alto sesgo de publicación. Discusión: La diferente prevalencia entre series clínicas y autopsias puede implicar que la detección de metástasis en tiroides en la clínica está infradiagnosticada. La razón de esto podría ser que las metástasis intratiroideas se presentan de forma asintomática siendo diagnosticadas como hallazgo casual en autopsias. En otras ocasiones se presentan como un nódulo tiroideo años después del tumor primario, lo que condiciona el diagnóstico. Conclusiones: La prevalencia de metástasis en tiroides es superior en las series de autopsias que en series clínicas (hasta 6.67 veces más frecuente en nuestro estudio). Las metástasis intratiroideas probablemente están infradiagnosticadas por cursar sin clínica siendo diagnosticadas como hallazgo casual en autopsias. Los tumores primarios más frecuentes fueron el riñón (series clínicas) y la mama (series de autopsias).

Colon Carcinoma Metastasis to the Thyroid Gland: Report of a Case with a Review of the Literature

Metastasis of colon cancer to the thyroid gland is very rare and we would like to report a case we have experienced, with a review of the literature. A 66-year-old woman noticed a swelling in the anterior neck area and sought medical attention at our department in August 2003. At age 63, she had undergone surgery for cancer of the ascending colon, but subsequently the cancer metastasized to the liver and she underwent an outer hepatic segmentectomy. Fine-needle aspiration cytology indicated adenocarcinoma with characteristic tall columnar cells, confirming our suspicion that metastasis from the ascending colon cancer had already occurred. Furthermore, lung metastasis was also suspected, because several nodules were found in the lungs. On August 13, resection of the left lobe of the thyroid gland and dissection of the cervical lymph nodes were performed. Histopathology showed metastasis of the ascending colon cancer to the thyroid and lymph nodes.

Comparative study of single-center patients with thyroid metastases from colorectal cancer and previously reported cases in the literature

Background

Thyroid metastases from colorectal cancer (CRC) are rare, both in clinical practice and in the literature; hence, their diagnosis, appropriate treatment, and prognostic factors require further investigations.

Methods

A retrospective analysis was performed for four cases of thyroid metastases from CRC, treated in our center between January 2005 and December 2015, and the relevant literature was searched using PubMed, resulting in the identification of 17 patients with detailed information available. The clinical data and follow-up information of our patients and the previously reported cases were collected and compared.

Results

The median age of the 21 patients was 59 years (44.5 and 66 years for our patients and the previously reported cases, respectively). Fifteen (71.4%) primary tumors were distributed throughout the distal colon or rectum (75% [3/4] in our center and 70.5% [12/17] in the previously reported cases). According to our analysis, we found that 81.0% of patients (17/21) showed concomitant lung metastasis. Among them, all four patients in our center showed lung metastasis, and 75% (3/4) developed thyroid metastases after the lung metastasis. In the previously reported cases, the corresponding proportions were 76.5 and 76.5% (13/17) of patients, respectively. The median time after primary tumor diagnosis to thyroid metastasis development was 28 months (26 months in our center and 35 months in the previously reported cases). One patient with advanced CRC in our center died 5 months after the thyroid metastasis was identified, while the remaining three patients are currently alive (longest follow-up time, 27 months). The median survival time after thyroid metastasis during 3 years of follow-up of the previously reported 17 patients was 12 months. There was no difference in the overall survival between patients treated non-surgically (8/21) and patients undergoing thyroidectomy alone or thyroidectomy with adjuvant therapy (13/21) (p = 0.388). In addition, we found that the overall survival of the patients whose other metastases were treated with radical treatment was superior to that in those treated with palliative treatment (p = 0.022).

Conclusions

Thyroid metastases from CRC are rare in clinical practice and are a manifestation of advanced CRC. The prognosis of patients with thyroid metastases from CRC is related to various factors, including the grade of malignancy of the primary lesion, the presence of other metastases, and whether the metastases are timely diagnosed and a radical treatment strategy is employed.