Evaluation and management of incidental thyroid nodules in patients with another primary malignancy

doi:10.1016/j.surg.2007.06.033

Surgery

Volume 142, Issue 4, October 2007, Pages 581-587

https://doi.org/10.1016/j.surg.2007.06.033 Get rights and content

Background

Studies indicate that incidentally discovered thyroid nodules ≥1 cm in size may have a higher rate of malignancy (7% to 29%) than traditionally discovered nodules (5%). We sought to determine the rate of malignancy in incidental thyroid nodules in patients with other malignancies, and examine the accuracy of ultrasound (US) versus computed tomography (CT) in determining nodule size.

Methods

We evaluated 41 patients with history of another known malignancy (gastrointestinal, 23; breast, 11; other, 7) referred with an incidental thyroid nodule. Patients underwent office-based US and biopsy of nodules ≥1 cm. Surgical intervention was based on biopsy results. We compared nodule size at pathology with size seen on CT or US.

Results

Thirty-five patients met criteria for biopsy. Of the 35, 20 (57%) had atypical biopsy results warranting resection. Sixteen of those 20 underwent surgery. Pathology yielded 4 papillary thyroid cancers (PTC), 4 microPTC, 2 metastatic cancers, and 7 benign lesions. Ultrasound measurement of nodules compared to size measured at pathology had an r² correlation value of 0.90 with P value <.0001. CT scan had an r² value of 0.83 and P value of .005.

Conclusions

Incidental thyroid nodules in patients with another primary malignancy warranted resection in 57%. The rate of malignancy in incidental thyroid nodules was 24%, which is above the expected rate of 5% seen in traditionally discovered nodules. US correlation with nodule size at pathology was excellent and superior to CT scan. Incidentally discovered thyroid nodules ≥1 cm, seen in patients with another malignancy, warrant further evaluation.

Section snippets

Methods

In this study, we evaluated 41 patients referred for an incidentally discovered thyroid nodule with a personal history of another primary malignancy. Data on the first 21 patients in the study (from July 2004 to November 2005) were collected retrospectively. Initial analysis of those data (not published) demonstrated an increased incidence of malignancy as compared with traditionally discovered thyroid nodules. Therefore, in December of 2005, a prospective database was then devised to collect

Results

During the study period, 41 patients with history of another primary malignancy were referred for surgical evaluation of an incidentally discovered thyroid nodule. The primary malignancy in these patients can be seen in Table I. Twenty-three patients were referred with a history of a primary gastrointestinal malignancy and 11 with breast cancer. The remaining 7 patients had a variety of other cancers. Of note, 9 patients had >1 primary malignancy documented in their past medical history. During

Discussion

Incidental thyroid nodules can be discovered during many radiographic imaging tests: CT, MRI, PET scan, carotid duplex US, neck US and various nuclear medicine tests. Patients with primary malignancies such as colon or breast cancer and lymphoma routinely undergo many of these tests as a part of their disease surveillance. Because of the precision of some of these modalities, large numbers of incidental nodules are being discovered. For example, the Department of Radiology at the Massachusetts

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Evaluation of Thyroid Incidentaloma
2014, Surgical Clinics of North America
Citation Excerpt :
In fact, incidental micropapillary thyroid cancers may be found in up to 13% of all thyroid pathology specimens in the United States.40) After exclusion of such micropapillary cancers, the data11,19 still suggest a possible 3-fold increased risk of cancer in incidental nodules compared with the traditional palpable thyroid nodule. As such, incidental thyroid nodules do warrant proper clinical investigation.
Incidental thyroid nodule: patterns of diagnosis and rate of malignancy
2009, American Journal of Surgery
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Kim et al reported a malignancy rate of 21.6% in Korean patients who underwent neck ultrasonography during routine health screening.8 Wilhelm et al reported a 24% rate of malignancy in patients with a history of a known nonthyroid malignancy and an incidental thyroid nodule.9 As was true in other series, most malignant thyroid incidentalomas in our patients were primary thyroid malignancies.4,5,15
The clinical significance of thyroid incidentalomas is controversial.
The rate of malignancy was determined for patients with an incidentally discovered thyroid nodule, and results were stratified according to imaging modality as well as presence and type of pre-existing malignancy.
One hundred fifty patients were identified, of which 88 with a known malignancy were screened for metastases. Twenty-three (15%) patients were diagnosed with thyroid malignancy. Incidental nodules identified on positron emission tomography scan were malignant in 33% of the patients compared with 11% for those identified on computed axial tomography (P = .016). The rate of thyroid malignancy in patients with pre-existing nonthyroid malignancy (18%) was not significantly different from patients without a history of malignancy (13%, P = .36).
Thyroid incidentalomas are associated with a high rate of malignancy. The rate of malignancy is highest for nodules discovered on positron emission tomography scan and is no different in patients with or without pre-existing malignancy.
Epidemiology of thyroid nodules
2008, Best Practice and Research: Clinical Endocrinology and Metabolism
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In a review of the results of 18,183 FNAs in seven large series, Gharib et al31 reported an overall accuracy of 95%, with non-diagnostic cytology rates of 5–21% (average 15%). Incidental thyroid nodules in patients with another primary malignancy warranted resection in 57% of cases seen by Wilhelm et al.32 The rate of malignancy in incidental thyroid nodules was 24%, which is above the expected rate of 5% seen in traditionally discovered nodules. Ultrasound correlation with nodule size at pathologic evaluation was excellent and was superior to correlation on computed tomographic scan.
Thyroid nodules are common and are commonly benign. The reported prevalence of nodular thyroid disease depends on the population studied and the methods used to detect nodules. Nodule incidence increases with age, and is increased in women, in people with iodine deficiency, and after radiation exposure. Numerous studies suggest a prevalence of 2–6% with palpation, 19–35% with ultrasound, and 8–65% in autopsy data. With widespread use of sensitive imaging in clinical practice, incidental thyroid nodules are being discovered with increasing frequency. Ultrasonography is the most accurate and cost-effective method for evaluating and observing thyroid nodules. Current ultrasonography machines are relatively inexpensive, sensitive, and easy to operate. Most endocrinologists are now using ultrasound examination in the initial evaluation of a patient with known or suspected thyroid nodule. The management of thyroid incidentalomas is a matter of controversy.
Utility of I-123 thyroid uptake scan in incidental thyroid nodules: An old test with a new role
2008, Surgery
Citation Excerpt :
As radiographic testing has improved in its ability to delineate small tissue abnormalities, and as screening and staging tests (e.g., CT and PET scans, carotid duplex) become more routinely utilized, incidental thyroid nodules are being found more frequently.9 These nodules have been found to carry an increased rate of malignancy (7%–29%) compared with traditionally discovered thyroid nodules.5-8 Thus, when a solitary incidental nodule ≥1 cm is discovered, it should be investigated in the same manner as all thyroid nodules.
In an incidentally discovered multinodular thyroid goiter, determining which nodule to biopsy is challenging. This study examined whether I-123 thyroid uptake scans (TUS) could guide this biopsy.
A retrospective review of 71 patients referred for evaluation of an incidentally discovered thyroid nodule was conducted. Patients with a multinodular thyroid underwent I-123 TUS.
Of 71 patients, 14 had multinodular thyroids. Average number of nodules per patient was 5.3 with an average size disparity between nodules of only 0.4 cm. TUS found an isolated “cold” nodule in 9 of 14 (64%) patients. “Cold” nodules represented cancer by biopsy or surgical pathology in 3 of 9 (33%) patients. A normal or “hot” TUS corresponded to benign pathology in 5 of 5 (100%) patients. This gave a “cold” nodule 100% sensitivity for finding cancer in a thyroid nodule, and a specificity of 45%.
Of patients referred for evaluation of an incidentally discovered thyroid nodule, 20% had multinodular disease. I-123 TUS have generally been removed from the treatment algorithm of thyroid nodules owing to the reliability of fine-needle aspiration biopsy. However, in the setting of a multinodular goiter, this test demonstrated utility by decreasing unnecessary, multiple biopsies in 71% of patients. This old test has gained a new role in the management of these challenging cases.
Metastatic renal cell carcinoma to the thyroid gland presenting 17 years after nephrectomy
2008, Diagnostic Histopathology
Citation Excerpt :
Cells of an RCC are rich in glycogen and lipid. A positive reaction of the tumour cell cytoplasm with periodic acid-Schiff without prior diastase digestion and with Oil Red O will further support the diagnosis of metastatic RCC.15,16 The time course of metastatic RCC to the thyroid is variable.
The most common metastatic tumour to masquerade as a primary thyroid tumour is renal cell carcinoma (RCC). Diagnosing metastatic RCC to the thyroid by fine needle aspiration (FNA) can be challenging and may yield cells readily mistaken for those of a follicular or papillary carcinoma. We report such a case in a 76-year-old patient who presented with a multinodular goitre. FNA cytology of the gland was reported as Thy4 with follicular cells showing a papillary architecture, vacuolated cytoplasm and intranuclear inclusions. The differential diagnosis of a metastatic neoplasm was not considered on the aspirate. Following a subsequent thyroid lobectomy, histology and immunohistochemistry indicated a diagnosis of metastatic RCC. Further enquiries revealed this patient had a radical nephrectomy for RCC 17 years previously. RCC is a tumour that metastasizes diffusely and in an unpredictable manner. Solitary metastases in the thyroid gland occur as late as 240 months from the date of nephrectomy. Secondary involvement of the thyroid gland by malignant metastases should be kept in mind when examining cytological and histological specimens.
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Central Surgical AssociationEvaluation and management of incidental thyroid nodules in patients with another primary malignancy

Background

Methods

Results

Conclusions

Section snippets

Methods

Results

Discussion

Surgery

Thyroid gland: US screening in a random adult population

Radiology

Thyroid incidentalomasPrevalence by palpation and ultrasonography

Ann Intern Med

The significance of incidental thyroid abnormalities identified during carotid duplex ultrasonography

Arch Surg

Significance of incidental thyroid lesions detected on CT: correlation among CT, sonography, and pathology

AJR

Uptake in In-111 pentreotide by normally functioning nodular goiters

Clin Nuclear Med

The significance of nontoxic thyroid nodules: final report of a fifteen year study of the incidence of thyroid malignancy

Ann Intern Med

Central Surgical Association
Evaluation and management of incidental thyroid nodules in patients with another primary malignancy