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  Table of Contents    
Year : 2019  |  Volume : 62  |  Issue : 1  |  Page : 122-124
Papillary carcinoma thyroid serving as recipient tumor to carcinoma breast: A rare example of tumor-to-tumor metastasis

1 Department of Pathology, Regional Cancer Centre, Thiruvananthapuram, Kerala, India
2 Department of Surgical Oncology, Regional Cancer Centre, Thiruvananthapuram, Kerala, India

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Date of Web Publication31-Jan-2019


A 36-year-old female presented with lump in the left breast of 2 months duration. Fine-needle aspiration cytology (FNAC) and trucut biopsy confirmed the diagnosis of carcinoma. Clinically, it was T3N1Mx disease. Computed tomography (CT) of the chest detected bilateral lung metastasis. CT head and neck detected a nodule in the thyroid which on FNAC was suspicious of papillary carcinoma. The patient was started on chemotherapy for breast disease with a good initial response; however, while on-follow up, there was progression of disease at primary site. The patient was taken up for surgery. Radical mastectomy along with total thyroidectomy was performed. Histopathological examination showed infiltrating duct carcinoma, not otherwise specified type and papillary carcinoma thyroid. There was a 0.4 cm × 0.4 cm metastatic focus, from breast carcinoma within the papillary carcinoma thyroid. The metastasis was confirmed by immunohistochemistry. Metastasis to thyroid is rare. However, tumor-to-tumor metastasis with papillary carcinoma serving as recipient to breast carcinoma is exceedingly rare with very few case reports in the literature. We report this case for its rarity and also for highlighting the fact that pathologists should keep in mind the possibility of metastasis also when coming across unusual morphology in thyroid lesions.

Keywords: Breast carcinoma, papillary carcinoma thyroid, tumor-to-tumor metastasis

How to cite this article:
Raveendrannair AK, Mathews A, Varghese BT, Jayasree K. Papillary carcinoma thyroid serving as recipient tumor to carcinoma breast: A rare example of tumor-to-tumor metastasis. Indian J Pathol Microbiol 2019;62:122-4

How to cite this URL:
Raveendrannair AK, Mathews A, Varghese BT, Jayasree K. Papillary carcinoma thyroid serving as recipient tumor to carcinoma breast: A rare example of tumor-to-tumor metastasis. Indian J Pathol Microbiol [serial online] 2019 [cited 2019 Jul 24];62:122-4. Available from: http://www.ijpmonline.org/text.asp?2019/62/1/122/251270

   Introduction Top

Tumor-to-tumor metastasis is diagnosed based on stringent criteria. The diagnosis of this rare condition requires that the recipient tumor is a true neoplasm and that the donor neoplasm is a true metastasis, that is, invasion into the substance of recipient neoplasm is proven. Furthermore, the presence of only tumor emboli within a recipient neoplasm does not qualify as a true tumor-to-tumor metastasis.[1],[2] Collision tumor, contiguous growth of one neoplasm into another adjacent neoplasm, and metastasis to a lymph node already involved by lymphoreticular malignancy are also excluded. The thyroid gland is highly vascularized; however, metastasis of tumors to the thyroid is relatively rare. The common primary sites causing metastasis to thyroid include breast, lung, and kidney. Metastasis to thyroid is rare; however, metastasis to a thyroid neoplasm, that is, tumor-to-tumor metastasis with thyroid neoplasm serving as recipient, is extremely rare with very few case reports in the literature.

   Case Report Top

A 36-year-old female presented to the outpatient clinic of our surgical oncology division with complaints of lump in the left breast of 2 months duration. There was no associated pain or nipple discharge. She also gave a history of breastfeeding her second child till 6 months back. On examination, she had a mass in the left breast and significantly enlarged lymph nodes in the left axilla. Clinically, she had T3N1Mx disease. Fine-needle aspiration cytology (FNAC) and trucut biopsy were performed which confirmed the diagnosis of carcinoma breast. On further workup, she was found to have bilateral lung metastasis on computed tomography (CT) chest. CT scan of the neck showed 5.6 cm × 3.8 cm nodule in the right lobe of thyroid. FNAC from thyroid nodule was reported as suspicious of papillary carcinoma. She was started on chemotherapy for breast disease. Thyroid surgery was planned after completion of chemotherapy for breast carcinoma. However, while on chemotherapy, though there was an initial response, later on, there was progression of the breast disease with increase in size of breast lump.

Mastectomy and total thyroidectomy were done. Thyroidectomy specimen on cut section showed a diffuse gray-white growth with adjacent colloid nodule. Within the growth was seen a whitish nodular area measuring around 0.4 cm × 0.4 cm which was in contrast with the gray-white granular growth of thyroid [Figure 1]. Histopathology of mastectomy specimen showed infiltrating ductal carcinoma, not otherwise specified [Figure 2]a and [Figure 2]b with lymph node metastasis. Section from the thyroid showed papillary carcinoma with a focus of metastatic breast carcinoma measuring 4 mm × 4 mm [Figure 2]c and [Figure 2]d. The histomorphology of the metastatic focus was similar to that of primary tumor in the breast [Figure 3]a. Immuohistochemistry showed thyroglobulin [Figure 3]b and thyroid transcription factor-1 (TTF-1) positivity in papillary carcinoma, while the metastatic focus was negative for both the markers.
Figure 1: Cut section of the right lobe of thyroid showing gray-white granular growth with a 4 mm × 4 mm whitish area within

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Figure 2: (a) Section from breast showing infiltrating duct carcinoma (H and E, ×200). (b) Higher power of infiltrating duct carcinoma breast with cells showing moderate amount of eosinophilic cytoplasm and pleomorphic nucleus with coarse chromatin (H and E, ×400). (c) Section from thyroid showing papillary carcinoma within which is seen a focus of metastatic breast carcinoma (H and E, ×200). (d) Higher power view showing papillary carcinoma thyroid with the classic pale vesicular nucleus along with adjacent area of metastatic breast carcinoma showing cells with similar morphology as primary breast carcinoma

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Figure 3: (a) Section from thyroid showing papillary carcinoma within which is seen a focus of metastatic breast carcinoma (H and E, ×40). (b) Thyroglobulin immunostain showing positive staining in papillary carcinoma and is negative in metastatic focus (immunohistochemistry, ×40)

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   Discussion Top

Thyroid gland is a highly vascular organ. In spite of this, the incidence of metastasis to thyroid is low though not rare. This may be due to the unfavorable microenvironment of thyroid.[3] The carcinomas known to metastasize to thyroid include lung, breast, kidney, and gastrointestinal tract. Malignant melanoma can also metastasize to thyroid. Head-and-neck cancers are known to locally infiltrate the thyroid. However, the incidence of tumor-to-tumor metastasis wherein thyroid neoplasm serves as recipient to another tumor is extremely rare.

Some authors are of the opinion that neoplastic thyroid gland may be fertile “soil” for tumor metastasis due to decreases in oxygen concentration, altered iodine content, and rich vascularity associated with neoplasia.[4] The mechanism of tumor-to-tumor metastasis is a complex process which is yet to be fully understood. The theories which are now being proposed are likely to be only part of the complex mechanism.

When a distinct dimorphic pattern is encountered in a thyroid neoplasm, the possibilities to be considered are poorly differentiated thyroid carcinoma, such as insular carcinoma and anaplastic carcinoma, arising in well-differentiated thyroid carcinoma. Contiguous spread from carcinomas of adjacent organs such as pharynx, larynx, trachea, or esophagus should also be kept in the differentials. Although not common, the possibility of metastasis should also be entertained, especially if the patient has another malignancy. Comparison of the morphology with that of the suspected donor tumor is most useful in suspected cases of tumor-to-tumor metastasis. Immunohistochemistry can be useful in sorting out difficult cases. In our case, the metastatic focus showed morphology similar to the breast carcinoma and was negative for markers of thyroid differentiation, namely TTF-1 and thyroglobulin. However, this may not be the situation in cases where the thyroid carcinoma is poorly differentiated or undifferentiated. In such situations, using markers such as TTF-1 and thyroglobulin may not be useful as the thyroid neoplasm will be negative for these markers.

There is previous case report in the literature of metastatic breast carcinoma coexisting with papillary carcinoma thyroid.[5] However, it was not a case of tumor-to-tumor metastasis like our case. A number of studies have evaluated breast cancer accompanying thyroid disease. There are studies in the literature showing association of breast cancer with autoimmune thyroid diseases as well as nonautoimmune thyroid diseases such as thyroid nodules with a high frequency, and the incidence of thyroid cancer is a known risk factor for breast cancer.[6],[7]

   Conclusion Top

Metastatic tumors in the thyroid gland are relatively uncommon; however, tumors metastasizing into other thyroid neoplasm are extremely rare. Clinical history of prior malignancy, presence of a dimorphic cell population, and comparison with surgical material of primary site is useful in diagnosing tumor-to-tumor metastasis involving the thyroid gland as recipient.[8] Our patient is on follow-up. She is being planned for adjuvant radiotherapy for the breast disease, thyroid remnant estimation will be done with scan and serum thyroglobulin levels, and treatment will be planned based on the results.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Bohn OL, De las Casas LE, Leon ME. Tumor-to-tumor metastasis: Renal cell carcinoma metastatic to papillary carcinoma of thyroid-report of a case and review of the literature. Head Neck Pathol 2009;3:327-30.  Back to cited text no. 1
Fadare O, Parkash V, Fiedler PN, Mayerson AB, Asiyanbola B. Tumor-to-tumor metastasis to a thyroid follicular adenoma as the initial presentation of a colonic adenocarcinoma. Pathol Int 2005;55:574-9.  Back to cited text no. 2
Czech JM, Lichtor TR, Carney JA, van Heerden JA. Neoplasms metastatic to the thyroid gland. Surg Gynecol Obstet 1982;155:503-5.  Back to cited text no. 3
Stevens TM, Richards AT, Bewtra C, Sharma P. Tumors metastatic to thyroid neoplasms: A case report and review of the literature. Patholog Res Int 2011;2011:238693.  Back to cited text no. 4
Yang SI, Park KK, Kim JH. Thyroid metastasis from breast carcinoma accompanied by papillary thyroid carcinoma. Case Rep Oncol 2014;7:528-33.  Back to cited text no. 5
Tanaka H, Tsukuma H, Koyama H, Kinoshita Y, Kinoshita N, Oshima A, et al. Second primary cancers following breast cancer in the Japanese female population. Jpn J Cancer Res 2001;92:1-8.  Back to cited text no. 6
Shin HW, Jang HW, Park JY, Chung JH, Min YK, Lee MS, et al. Clinico-pathologic characteristics of the primary thyroid cancer in patients with breast cancer. J Korean Endocr Soc 2009;24:240-6.  Back to cited text no. 7
Kameyama K, Kamio N, Okita H, Hata J. Metastatic carcinoma in follicular adenoma of the thyroid gland. Pathol Res Pract 2000;196:333-6.  Back to cited text no. 8

Correspondence Address:
Anila Kunjulekshmyamma Raveendrannair
Department of Pathology, Regional Cancer Centre, Thiruvananthapuram - 695 011, Kerala
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/IJPM.IJPM_672_17

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