Real-time ultrasonography of thyroid nodules

OPNa Overexpression Is Associated with Matrix Calcification in Thyroid Cancer Cell Lines

Osteopontin (OPN) spliced variants (OPN-SV: OPNa, OPNb, and OPNc) are aberrantly expressed in tumors and frequently associated with cancer progression. This holds true for papillary thyroid carcinoma (PTC), which is the most common type of thyroid cancer (TC). PTC often presents with desmoplasia and dystrophic calcification, including psammoma bodies (PB). This work aimed to investigate total OPN (tOPN) and OPN-SV expression and their association with the presence of PB in the PTC classical variants (cPTC), as well as the involvement of OPN-SV in matrix calcification of TC cell lines. We found that cPTC samples presenting PB showed higher OPN expression levels. In TC cell lines, OPNa overexpression promotes higher matrix calcification and collagen synthesis when compared to that of clones overexpressing OPNb or OPNc. In response to OPN knockdown, calcification was inhibited, paralleled with the downregulation of calcification markers. In conclusion, our data evidenced that OPN expression is associated with the presence of PB in cPTC samples. Among the OPN-SV, OPNa is the main contributor to matrix calcification in tested TC cells, providing clues to a better understanding on the biology and ethiopathogenesis of the calcification process in TC cells.

Relationship between patterns of calcification in thyroid nodules and histopathologic findings

Various patterns of calcification have been detected in benign and malignant thyroid nodules on ultrasonography (US). Microcalcification has been found to be highly associated with papillary thyroid carcinoma. However, other patterns of calcification have unclear clinical significance. The aim of this study was to evaluate which pattern of calcification could be predictive of malignancy. A total of 1,431 thyroid nodules of 1,078 patients who received preoperative ultrasound examinations and subsequently underwent thyroidectomy were retrospectively reviewed. The types of calcification were defined as follows: microcalcification, annular-like peripheral calcification, crescent-like peripheral calcification, intranodular coarse calcification, and calcified spot. Of these 1,431 nodules, 1,305 (91.1%) were thyroid carcinomas and 126 (8.9%) were benign nodules. Calcifications were detected in 38.6% (552/1,431) of all nodules. Calcifications were found in 40.2% (524/1,305) of malignant nodules and 22.2% (28/126) of benign nodules. Of the 524 malignant nodules with calcification, microcalcification was the most common pattern, occurring in 42.9% (225/524), and annular type was the least common pattern, occurring in 5.9% (31/524). Among the calcification types, only microcalcification and intranodular had a significant association with malignancy (p = 0.001, 0.035), with OR values of 3.5 (95% CI, 1.6-7.7) and 2.4 (95% CI, 1.1-5.6). Though using the patterns of calcification alone for predicting malignancy had limitation, microcalcification and intranodular calcification were significantly associated with malignancy.

US Features of Thyroid Malignancy: Pearls and Pitfalls

Thyroid nodules are common and occur in up to 50% of the adult population; however, less than 7% of thyroid nodules are malignant. High-resolution ultrasonography (US) is commonly used to evaluate the thyroid gland, but US is frequently misperceived as unhelpful for identifying features that distinguish benign from malignant nodules. Microcalcifications are one of the most specific US findings of a thyroid malignancy. Other useful US features include a marked hypoechogenicity, irregular margins, and the absence of a hypoechoic halo around the nodule. Lymphadenopathy and local invasion of adjacent structures are highly specific features of thyroid malignancy but are less commonly seen. The number, size, and interval growth of nodules are nonspecific characteristics. Suspicious US features may be useful for selecting patients for fine-needle aspiration biopsy when incidental nodules are discovered and when multiple nodules are present. Common interpretative pitfalls that may lead to failure to recognize a malignancy include mistaking cystic or calcified nodal metastases for nodules in a multinodular thyroid, mistaking diffusely infiltrative thyroid carcinomas and multifocal carcinomas for benign disease, and failing to recognize microcalcifications in papillary thyroid cancer.

Thyroid calcification and its association with thyroid carcinoma

AIM

Calcification within the thyroid gland may occur in both benign and malignant thyroid disease, and its detection on ultrasonography is frequently dismissed by many clinicians as an incidental finding of little significance. As a tertiary referral center, most of our thyroid patients will have had thyroid ultrasonography before being referred to us, and in our experience, the incidence of malignancy in a thyroid nodule containing calcification seems to be higher than that in the average thyroid nodule. To assess this risk, we conducted this retrospective review.

MATERIALS AND METHODS

Our analysis included 462 consecutive patients who underwent thyroid surgery at our institution between 1995 and 1999. We reviewed all the patients' charts for data regarding clinical findings, preoperative diagnostic investigations, and histopathologic diagnosis. Of the 462 patients, 361 (78.1%) had thyroid ultrasonography before surgery, and 49 (13.6%) of these ultrasounds showed intrathyroidal calcification.

RESULTS

Of the 49 patients whose ultrasounds showed intrathyroidal calcification, 29 (59.2%) were found on histopathologic examination to have thyroid carcinoma. Twelve of the remaining 20 patients had multinodular goiters. Of the 29 patients with malignancy, seven (24.1%) had preoperative fine-needle aspirates that were reported as benign. After excluding patients who were initially seen with multinodular disease, in the subset of 37 patients who presented with a solitary thyroid lesion with calcification, 28 (75.7%) were found to have carcinoma.

CONCLUSIONS

When calcification is noted within a solitary thyroid nodule, the risk of malignancy is very high. Surgery should be recommended regardless of the result of fine-needle aspiration cytologic findings.

Thyroidectomy or Radioiodine? The Value of Ultrasonography and Cytology in the Assessment of Nodular Lesions in Graves’ Hyperthyroidism

Although diffuse toxic goiter is a classical feature of Graves’ disease (GD) nodular goiters are occasionally found in some patients. The aim of the present study was to investigate the ultrasonographic and corresponding cytological manifestations in GD patients with nodular lesions to decide on a therapeutic strategy. Twenty-seven consecutive GD patients with nodular goiter were included in this study (21 women and six men, mean age 41.2 years, range 22–77 years). All underwent thyroid ultrasonography and fine-needle aspiration cytology. Of the 27 patients eight underwent surgical intervention because papillary thyroid carcinoma or follicular neoplasm was diagnosed by cytology; five of these were shown to have papillary thyroid carcinomas. Ultrasonography revealed the malignant nodules to be hypoechogenic, heterogeneous, and with ill-defined margins in four of these five thyroid cancers, whereas the remaining sonogram showed a cystic change and cauliflower-like tumor formation with microcalcification. The volume and maximal diameter of cancerous nodules were significantly larger than those of benign nodules. In conclusion our results reveal that ultrasonography and fine-needle aspiration cytology are reliable and quick methods for diagnosing nodular goiters in GD patients. If thyroid neoplasms are found ablative therapy with thyroidectomy is indicated instead of radioactive iodine.

Relative risk of cancer in sonographically detected thyroid nodules with calcifications

PURPOSE

The aim of this prospective study was to evaluate the significance of sonographically detected thyroid calcifications in the diagnosis of thyroid cancer.

METHODS

One hundred eighty-eight patients with thyroid disease, including 37 with thyroid cancer, were included in the study. Each patient underwent preoperative, high-resolution sonography to evaluate the thyroid gland for the presence of calcifications.

RESULTS

The highest incidence of calcification was found in thyroid cancer (54%), followed by multinodular goiter (40%), solitary nodular goiter (14%), and follicular adenomas (12%). The incidence of cancer was significantly higher in calcified nodules (29%) than in noncalcified nodules in the entire group (14%) (p = 0.019), with a relative risk of 2.5. In the group of solitary thyroid nodules, the incidence of cancer in the calcified nodules (55%) was higher than in the nodules without calcification (23%) (p = 0.016). Multiple noncalcified thyroid nodules harbored cancer in only 5% of cases. Compared with multiple noncalcified thyroid nodules, the solitary calcified nodules demonstrated a relative risk of 22.8. In both the solitary and multiple nodules, the relative risk in the presence of calcification was about the same, around 4. Patients younger than 40 years with calcified nodules constituted a high-risk group, with a relative risk of 3.8 versus 2.5 in patients older than 40 years with calcified nodules.

CONCLUSIONS

The detection of thyroid calcifications by sonography is diagnostically valuable, especially in cases involving a solitary nodule or a young person. The presence of calcifications in these cases should raise the suspicion of malignancy. The low incidence of cancer in patients with multiple noncalcified thyroid nodules suggests that a more conservative approach may be appropriate in such cases.

Thyroid Ultrasonography—A Review

OBJECTIVE

To review the major applications of ultrasonography in studies of the thyroid gland by clinical endocrinologists.

METHODS

The techniques for performance of thyroid ultrasonography and ultrasound-guided fine-needle aspiration biopsy are outlined, and the settings for their use are discussed. Characteristic findings and limitations are described.

RESULTS

In two situations--the assessment of thyroid nodules and the postoperative follow-up of thyroid cancer--ultrasonography and ultrasound-guided fine-needle aspiration biopsy have proved to be clinically useful when used in combination. On ultrasonography, a hyperechoic nodule with a sharp "halo" is associated with a low risk of malignancy and a hypoechoic nodule with microcalcifications is associated with a high risk of a malignant lesion, but performance of a biopsy is recommended. Ultrasonography coupled with ultrasound-guided fine-needle aspiration biopsy can detect >90% of recurrent cases of thyroid carcinoma. In general, normal lymph nodes appear flattened on ultrasonography, whereas malignant nodes appear more rounded or bulging.

CONCLUSION

Thyroid ultrasonography and fine-needle aspiration biopsy are complementary diagnostic procedures in the evaluation of thyroid nodules and for detection of recurrent or metastatic thyroid carcinoma.

Ultrasonic evaluation of benign and malignant nodules in echographically multinodular thyroids

In 165 patients with ultrasound findings of multinodular thyroids in whom thyroid resection was performed, sonographic features and pathohistologic findings of removed nodules were analyzed. Of 426 nodules removed, 70 were carcinomas and 356 benign. Carcinomas are more often hypoechogenic (p < 0.01) and contain nodular calcifications (p < 0.01), while benign nodules are more often iso-hyperechogenic (p < 0.01), showing intranodular cystic degenerative changes (p < 0.01) and perinodular hypoechogenic rim (p < 0.01). Mean diameter of carcinomatous nodules is lower than in benign nodules (p = 0.022). The relative proportion of malignant nodules is highest in the upper halves of thyroid lobes (p < 0.01). Although certain sonographic signs increase the likelihood of a given lesion being malignant or benign, the lack of absolute specificity in the ultrasound evaluation of thyroid nodules was confirmed.

Lymphoproliferative disorders of the thyroid gland: radiological appearances

Images of lymphoproliferative disorders of the thyroid by ultrasonography (US), computed tomography (CT), 99Tcm and 67Ga scintigraphy were analysed in eight patients (two men and six women, aged 42-83 years). Seven patients were diagnosed as having primary lymphoma and one plasmacytoma. Ultrasound revealed a solid mass with homogeneous and very low echogenicity clearly distinguishable from residual thyroid tissue in five patients, diffuse hypoechoic goitre in one and multiple irregular hypoechoic nodules in both lobes in the patient with plasmacytoma (Case 8). Computed tomography demonstrated a focal low-density area in six cases of lymphoma and decreased density throughout the gland in the other two patients. 99Tcm scintigraphy showed hemilobar enlargement with decreased and uneven trapping, cold area or complete lobar defect in six patients with lymphoma and no trapping in the case of plasmacytoma. 67Ga scintigraphy demonstrated high accumulation in lymphoma and faint accumulation in the case of plasmacytoma. Radiological manifestations with a focal lesion were considered typical and diagnostic of primary thyroid lymphoma, while in one case with diffuse infiltration through the whole gland, the differential diagnosis from Hashimoto's thyroiditis could not be made. In the final case, cells infiltrated diffusely to form islands with patchy distribution among well preserved follicles, correlating with the multiple hypoechoic areas observed by US.

Solitary thyroid nodule: a prospective evaluation of nuclear scanning and ultrasonography

The aim of this study was to assess prospectively the value of thyroid nuclear scans and ultrasound examination in the preoperative investigation of patients with a solitary thyroid nodule. Total thyroid lobectomy for a solitary thyroid nodule was performed in 68 cases. Each patient had a thyroid isotope scan (except two women who were pregnant) and thyroid ultrasound examination. There were 10 (15 per cent) malignant nodules, 11 (16 per cent) benign neoplastic nodules and 47 (69 per cent) benign non-neoplastic nodules. All of the patients with malignant nodules who were scanned had a solitary cold nodule on thyroid scan, as did 40 (69 per cent) of those with benign solitary nodules. Ultrasound examination of the thyroid suggested correctly that one of 16 (6 per cent) cystic lesions, four of 16 (25 per cent) complex solid-cystic lesions and three of 18 (17 per cent) of solid lesions were malignant. One lesion reported as multinodular on ultrasonography and one reported as normal also turned out to be malignant. Thyroid isotope scans and ultrasound do not accurately differentiate between benign and malignant conditions and their routine use in the investigation of a solitary thyroid nodule should be abandoned.