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| Journal of the New Zealand Medical Association,
28-October-2005, Vol 118 No 1224
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Metastatic thyroid carcinoma
Hakan
Kaya, Umut Barbaros, Yeşim Erbil, Alp Bozbora, Yersu Kapran, Ferihan Aral,
Selçuk Özarmağan
Although thyroid is a common target for metastasis,
clinically significant metastases to the thyroid gland are rare.1–4
Fourteen percent of renal cell carcinoma patients have systemic disease, but
metastasis to the thyroid is rare.5,6 Here we report on a patient operated on 2
years previously for renal cell carcinoma and now presenting with a nodular
goitre, which turned out to be metastasis of the primary neoplasm.
Case reportIn July 2004, a 58-year-old Turkish man was referred to our
department for a nodular goitre. His physical examination revealed a palpable
thyroid gland. He had been operated on for renal cell carcinoma (left
nephrectomy) 2 years previously and the tumour was now a 7 cm mass. Pericapsular
invasion was not seen, but tumour thrombus at the renal vein was detected.
A thyroid ultrasonography (US) showed enlargement of the
gland as well as multiple hypoechoic, solid, well-defined mass lesions.
Scintigraphy revealed a hypoactive nodule in the left lobe, and a hyperactive
nodule in the right lobe.
Thyroid hormone levels were within the normal range of the
laboratory’s reference values. US-guided fine needle aspiration biopsy
(FNAB) of the gland showed cytological findings suggestive of a follicular
tumour. Adenomatous nodule and microinvasive follicular carcinoma discrimination
could not be made. Cytological studies were evaluated without knowing the
history of the patient.
There were large neoplastic cells with scant cytoplasm
misdiagnosed as a follicular tumour. A bilateral total thyroidectomy was
performed. Our patient had a multinodular goitre with a suspicious lesion
revealed by FNAB. (We prefer near-total thyroidectomy for our patients with
multinodular goitres.) This approach is supported by previous reports showing
that a near-total thyroidectomy may prevent subsequent recurrent thyroid
operations.7 When we viewed the suspicious lesion via a FNAB, we considered the
preferred surgical strategy for this patient to be a near-total thyroidectomy.
The pathological examination of the specimen revealed five
nodular lesions. The nodules had similar histopathological features; the renal
cell carcinoma and immunohistochemical examination confirmed the diagnosis of
metastasis of renal cell carcinoma (Figures 1 and 2). The
tumour had vimentin and pancytokeratin expression, and thyroglobulin
immunoreactivity was not observed.
The patient did not have any postoperative complications and
was discharged from hospital on the postoperative first day.
DiscussionMetastasis to the thyroid gland are found in about
3–24% of autopsies of patients who died due to malignancies at other
primary sites. Metastatic carcinomas are not common in clinical practice but
metastasis to the thyroid gland has been reported in renal cell carcinoma,
breast cancer, lung cancer, gastrointestinal malignancies, malignant melanoma,
sarcoma, haematologic malignancies, and other genitourinary cancers.3,8
Renal cell carcinoma is often seen at the sixth decade and
with male dominance; it tends to often show a slow progression in its clinical
course with a late development of metastasis.1–4
Metastases of renal cell carcinoma occurs in the respiratory
system, skeletal system, lymph nodes, brain, liver, skin, and other sites such
as at the thyroid gland.8–11 In a study by Chen et al, 10 patients were
reported with isolated thyroid metastasis during a 8-year period, of whom 8 had
metastasis of renal cell carcinoma.4 Metastasis may be the initial presentation
of the disease-mimicking primary thyroid neoplasm, which can be a diagnostic
dilemma for both the surgeon and the pathologist.9
Patients with metastasis to the thyroid may present with
symptoms related to the mass caused by the tumour, although many effects are
asymptomatic. The time interval between the primary malignancy and the
metastasis may be long enough to make a misdiagnosis of primary thyroid
tumour.4,9
If the patient has a history of carcinoma, metastasis of the
neoplasm should be kept in mind, although high oxygen tension and iodine makes
the thyroid gland resistant to metastasis. Radiographic differences are not
useful since both primary tumours and metastatic lesions of the thyroid gland
will appear as cold nodules on scintigraphy and as a inhomogenius, hypoechoic
mass on ultrasonography. Therefore, fine needle aspiration biopsy can be useful
in detecting an unsuspected malignancy.2–5
The appearance of metastatic disease in the thyroid gland is
a sign of poor survival because it indicates disseminated disease. It has been
reported that patients may benefit from surgery, however.6,8 In the study by
Chen et al,4 mean survival was 34 months with thyroidectomy (with or without
adjuvant therapy), which is longer than the 25 months mean survival time of
patients treated with modalities other than surgery. Furthermore, after a median
follow-up of 5.2 years, 60% percent of patients were alive and two patients were
disease-free.
Factors that contribute to a favourable prognosis are a long
interval between the occurrence of primary disease and the development of the
metastatic focus; a solitary or isolated lesion; spontaneous regression of the
metastatic lesions; necrosis in the resected specimen; and slow tumour growth.5
In cases of solitary metastasis, the 5-year survival rate
from the date of nephrectomy is reported to be 30% to 70%, while it dramatically
drops to 5% in cases of disseminated disease.3 There is no clear consensus on
the role of surgical treatment of metastatic thyroid disease. Most authors
recommend lobectomy/isthmusectomy when there is a solitary nodule or airway
obstruction.4
ConclusionIn any patient with a history of malignancy, a new thyroid
mass should be considered as a recurrence until proven otherwise. Fine needle
aspiration biopsy can help discriminate between primary and metastatic
neoplasms. Although metastasis is an indication of disseminated disease, some
patients may benefit from aggressive surgery of metastatic solitary
lesions.
Author information:
Hakan Kaya, General Surgeon, Department of General Surgery; Umut
Barbaros, General
Surgeon, Department of General Surgery; Yeşim Erbil, General Surgeon,
Department of General Surgery; Alp Bozbora, General Surgeon, Department of
General Surgery; Yersu Kapran, Pathologist, Department of Pathology; Ferihan
Aral,
Endocrinologist,
Department of Pathology; Selçuk Özarmağan, General
Surgeon, Department of General Surgery; Istanbul Medical School, Istanbul
University, Istanbul, Turkey
Correspondence:
Yeşim Erbil, Department of General Surgery, Istanbul Medical School,
Istanbul University, Capa, 34390, Istanbul, Turkey. Fax: +90 212 6619771;
email: yerbil2003@yahoo.com
References:
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