Ann Thorac Surg 2009;88:2016-2017. doi:10.1016/j.athoracsur.2009.04.134
© 2009 The Society of Thoracic Surgeons
Case Reports
Solitary Lung Metastasis Diagnosed 30 Years After Surgery for Thyroid Cancer
Hisayuki Shigematsu, MDa,*,
Akio Andou, MDa,
Arubi Teramoto, MDa,
Kiyoshi Matsuo, MDb,
Wakako Oda, MDc,
Ichiro Yamadori, MDc,
Ryohei Higashi, MDa
a Department of Chest Surgery, NHO Okayama Medical Center, Okayama, Japan
b Department of Respiratory Medicine, NHO Okayama Medical Center, Okayama, Japan
c Department of Pathology, NHO Okayama Medical Center, Okayama, Japan
Accepted for publication April 28, 2009.
* Address correspondence to Dr Shigematsu, Department of Chest Surgery, NHO Okayama Medical Center, 1711-1 Tamasu, Okayama, 701-1192, Japan (Email: h-shige{at}ba3.so-net.ne.jp).
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Abstract
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A 75-year-old woman with a history of extrapulmonary malignancies (ie, thyroid cancer and colon cancer) underwent a lobectomy for a solitary nodule in the left lung. Pathologic examination showed a lung metastasis from papillary thyroid cancer treated 30 years earlier. Solitary metastasis to the lung from thyroid cancer is unusual, and our case presented the long interval from initial treatment to the identification of metastasis. A careful follow-up is mandatory, and one should keep in mind the delayed metastasis in the patient with differentiated thyroid cancer.
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Introduction
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The diagnosis of a solitary pulmonary nodule in patients with a history of extrapulmonary malignancy is usually difficult. Pulmonary metastases from thyroid cancer usually presents as a multiple nodular pattern. Solitary metastasis to the lung from thyroid cancer is quite rare and there are limited reports concerning this entity. We describe an unusual case of solitary pulmonary metastasis from thyroid cancer 30 years after initial treatment.
A 75-year-old Japanese woman (who history involved never smoking) was referred to our institute for the evaluation of a solitary nodule in the left lung. She was asymptomatic and had been in good health. She underwent a left thyroid lobectomy for stage III papillary thyroid cancer (T1N1aM0) 30 years previously (at the age of 45) and a colectomy for Dukes' A colorectal cancer 3 years previously. A computed tomographic scan demonstrated a well-defined and lobulated nodule without calcifications measuring 23 mm in the left lower lobe (Fig 1A). Routine laboratory tests were normal, except for carcinoembryonic antigen level, which was slightly increased (7.6 ng/mL). The serum thyroid-stimulating hormone and thyroglobulin were not evaluated at the time of admission. Transbronchial biopsy by bronchoscopy was nondiagnostic. A positron emission tomographic image showed an increase in the accumulation of 18F-fluorodeoxyglucose with maximum standardized uptake value of 8.9 only within the pulmonary lesion (Fig 1B), suggesting that the nodule was a malignant tumor without metastatic disease. As the possibilities, which included primary lung cancer or metastatic lung cancer from colon cancer, a left lower lobectomy was performed to obtain a definitive histologic diagnosis and to accomplish a complete removal of the tumor. Because the tumor was located centrally, partial resection or segmentectomy was not indicated for fear of a positive surgical margin. Microscopic examination of the resected tumor revealed a well-differentiated papillary adenocarcinoma with psammoma bodies and necrosis in the central lesion (Fig 2A). Follicular spaces filled with dense eosinophilic colloidal material were also observed. Immunohistochemically, cancer cells were positive for thyroid transcription factor-1, surfactant protein-A, thyroglobulin (Fig 2B), and cytokeratin (CK) 7, but were negative for CK 20. These findings were consistent with a diagnosis of pulmonary metastasis from papillary thyroid cancer treated 30 years earlier. The patient had an uneventful hospital course and was discharged on postoperative day 10. After lung metastasectomy, thyroid ultrasonography was performed and showed no abnormalities in the residual thyroid gland. Serum thyroid-stimulating hormone and thyroglobulin levels were within the normal range.
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Fig 1. (A) Computed tomographic scan shows a lobulated nodule measuring 23 mm in the left lower lobe without lymphadenopathy. (B) Positron emission tomographic imaging shows the accumulation of 18F-fluorodeoxyglucose with maximum standardized uptake value of 8.9 in the solitary nodule.
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Fig 2. (A) Resected tumor revealed a well-differentiated papillary adenocarcinoma histologically. (Hematoxylin & eosin; x100). (B) Cancer cells were immunohistochemically positive for thyroglobulin. (Thyroglobulin; x100.)
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Comment
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The lung is one of the most common target organs for metastasis from various malignancies and metastatic lesions manifest radiographically as solitary or multiple nodular patterns. The accurate diagnosis of a solitary pulmonary nodule in patients with a history of extrapulmonary malignancy is usually difficult and important to proceed to the optimal treatment. The possibilities include primary lung cancer, metastatic lung cancer, and benign tumor, such as granulomas and hamartomas. Surgical resection, chemotherapy, radiation, observation, or combined approaches are proposed depending on the cause of such a nodule. Although histological confirmation was not obtained before surgical resection in the present case, we considered this as a primary lung cancer or metastatic lung cancer from colon cancer because of the 18F-fluorodeoxyglucose uptake on positron emission tomographic imaging and her past medical history. We missed the possibility of metastasis from thyroid cancer because of the long disease-free interval (30 years) from the initial treatment and the radiographic images. Pulmonary metastases from thyroid cancer usually present as multiple nodular pattern or miliary pattern throughout both lungs. Consequently, surgical resection is not considered, but iodine-131 therapy is applied for these lesions after total thyroidectomy, if indicated. Solitary metastasis to the lung from thyroid cancer is quite rare and a few cases have been reported in the English literature [1–5]. All cases were female gender and papillary carcinoma type, as in our case. Three were the occult thyroid cancer cases diagnosed after metastasectomy. Two were the cases presenting as a pulmonary metastasis after thyroidectomy. Because a preoperative diagnosis of a pulmonary nodule was not established in all cases, except for one, surgical resection should then be an acceptable approach for the correct diagnosis and treatment. Tubiana and colleagues [6] reported that 12 of 49 (24%) recurrent cases, including pulmonary metastases, occurred more than 20 years after initial treatment in patients with differentiated thyroid cancer; they stated that patients must be followed for their entire lives. They suggested that the longer doubling time and dormant state during the progression influence the natural history of thyroid cancer, which is known to be indolent and has a good prognosis. The present case accounts for one of the longest intervals between thyroidectomy and pulmonary metastasis.
Several tumor markers and CKs have been developed as the immunohistochemical tools in the diagnosis of cancers. Cytokeratins 7 and 20 are the most commonly used CKs in surgical pathology, and the expression patterns of these are helpful to detect its origin in the differential diagnosis of pulmonary tumors. Lung adenocarcinomas and thyroid tumors were usually CK7-positive and CK20-negative pattern, and colorectal cancers were usually CK7-negative and CK20-positive pattern [7]. Thyroglobulin produced by only thyroid tissues is also a valuable marker distinguishing cancers of thyroid origin and other organs. The combination of these markers in immunohistochemical analysis is beneficial to identify its origins in the differential diagnosis of malignant lung tumor.
When a solitary lung nodule is encountered in a patient with a history of thyroid cancer, even the long disease-free period, the possibility of delayed metastasis must be kept in mind. We conclude that careful follow-up is mandatory, even years after treatment for differentiated thyroid cancer.
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References
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- Levi E. Carcinoma of thyroid with metastasis to lungs N Y State J Med 1975;75:1544-1546.[Medline]
- Strate SM, Lee EL, Childers JH. Occult papillary carcinoma of the thyroid with distant metastasis Cancer 1984;54:1093-1100.[Medline]
- Harach HR, Franssila KO. Occult papillary carcinoma of the thyroid appearing as lung metastasis Arch Pathol Lab Med 1984;108:529-530.[Medline]
- Fonseca P. Thyroid lung metastasis diagnosed 47 years after thyroidectomy Ann Thorac Surg 1999;67:856-857.[Abstract/Free Full Text]
- Sakairi Y, Yasufuku K, Iyoda A, et al. A solitary metastatic lung tumor from thyroid papillary carcinoma diagnosed by endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA): report of a case Surg Today 2008;38:46-48.[Medline]
- Tubiana M, Schlumberger M, Rougier P, et al. Long-term results and prognostic factors in patients with differentiated thyroid carcinoma Cancer 1985;55:794-804.[Medline]
- Chu P, Wu E, Weiss LM, et al. Cytokeratin 7 and cytokeratin 20 expression in epithelial neoplasms: a survey of 435 cases Mod Pathol 2000;13:962-972.[Medline]
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Abstract
Introduction
