Imaging of Thyroid Cancer

Thyroid lymphoma

PURPOSE OF REVIEW

To highlight recent advances in our understanding of the epidemiology, incidence, evaluation, management and outcomes of primary thyroid lymphoma (PTL), and highlight the indications and limitations of surgery.

RECENT FINDINGS

The differential diagnosis of a rapidly enlarging thyroid mass with or without obstructive symptoms should include PTL and anaplastic thyroid cancer. When PTL is suspected, initial investigations should include blood tests and ultrasound-guided biopsy preferably core need biopsy to allow tissue typing and immunohistochemistry analysis. Systemic imaging with FDG PET-CT is required for staging. Surgery is not recommended for treatment purposes and should be reserved for diagnosis and airway management. Treatment includes chemotherapy and radiotherapy and offer an excellent prognosis.

SUMMARY

PTL is a rare malignancy making diagnosis and management challenging. Initial investigations of suspected PTL should include blood tests and ultrasound-guided biopsy, preferably core needle biopsy and systemic imaging is required for staging. Surgery is reserved for diagnosis and airway management. Chemotherapy and radiotherapy are the treatment of choice.

Effectiveness of core needle biopsy in the diagnosis of thyroid lymphoma and anaplastic thyroid carcinoma: A systematic review and meta-analysis

BACKGROUND

Both anaplastic thyroid carcinoma (ATC) and thyroid lymphoma (TL) clinically present as rapidly enlarging neck masses. Unfortunately, in this situation, like in any other thyroid swelling, a routine fine-needle aspiration (FNA) cytology is the first and only diagnostic test performed at the initial contact in the average thyroid practice. FNA, however, has a low sensitivity in diagnosing ATC and TL, and by the time the often "inconclusive" result is known, precious time has evolved, before going for core-needle biopsy (CNB) or incisional biopsy (IB) as the natural next diagnostic steps.

OBJECTIVES

To determine the diagnostic value of CNB in the clinical setting of a rapidly enlarging thyroid mass, via a systematic review and meta-analysis of the available data on CNB reliability in the differential diagnosis of ATC and TL.

METHODS

A PubMed, Embase and Web of Science database search was performed on June 23th 2021. Population of interest comprised patients who underwent CNB for clinical or ultrasonographical suspicion of ATC or TL, patients with a final diagnosis of ATC or TL after CNB, or after IB following CNB.

RESULTS

From a total of 17 studies, 166 patients were included. One hundred and thirty-six were diagnosed as TL and 14 as ATC following CNB. CNB, with a sensitivity and positive predictive value of 94,3% and 100% for TL and 80,1% and 100% for ATC respectively, proved to be superior to FNA (reported sensitivity for TL of 48% and for ATC of 61%). Furthermore, the need for additional diagnostic surgery after CNB was only 6.2% for TL and 17.6% for ATC.

CONCLUSIONS

Immediately performing CNB for a suspected diagnosis of ATC and TL in a rapidly enlarging thyroid mass is more appropriate and straightforward than a stepped diagnostic pathway using FNA first and awaiting the result before doing CNB.

Imaging of Treated Thyroid and Parathyroid Disease

The thyroid and parathyroid glands are endocrine structures located in the visceral space of the infrahyoid neck. Imaging plays a critical role in the evaluation of patients with thyroid cancer, both in the pre and posttreatment setting. Disorders of thyroid function, that is, hyperthyroidism and hypothyroidism, are also fairly common, although imaging utilization is less frequent with these conditions. Parathyroid dysfunction results in disordered calcium metabolism. Imaging is frequently applied in the preoperative assessment of these patients undergoing parathyroidectomy; however, routine imaging in the postoperative setting is uncommon. Parathyroid carcinoma is rare; however, imaging may be used in the pre and posttreatment setting.

Dedifferentiated liposarcoma of the thyroid gland: A case report

Liposarcoma is one of the most common soft tissue tumors that affect adults. Liposarcoma is typically identified in the retroperitoneum, trunk and extremities as a slow-growing mass, yet is rare in the thyroid gland. Herein, we report a case of dedifferentiated liposarcoma that developed in the thyroid gland, and performed a literature review. A 66-year-old male with a history of well-differentiated liposarcoma in the thymus presented with a rapidly enlarging mass in the thyroid gland. Malignancy was suspected due to the local extension of the tumor, and complete resection of the tumor was achieved. Tissue diagnosis from the tumor following surgery revealed that dedifferentiated liposarcoma, and tumor progression was difficult to control with adjuvant radiation and chemotherapy. This is, to the best of our knowledge, the first case to report dedifferentiated liposarcoma in the thyroid gland, and the difficulty in initial diagnosis as well as the aggressive features of dedifferentiated liposarcoma are highlighted.

Chapter 4 Thyroid Malignancy: Staging and Restaging

Determining the extent of disease is necessary for guiding the management of thyroid carcinomas. Diagnostic imaging, including ultrasound, computed tomography, magnetic resonance imaging, and nuclear medicine scans, plays an essential role in staging and restaging of thyroid carcinomas. This article reviews the approaches and imaging findings for evaluating the primary tumor, regional lymph node metastases, and distant metastases. In addition, potential pitfalls are discussed and depicted.

Clinical Presentation and Diagnostic Challenges of Thyroid Lymphoma: A Cohort Study

BACKGROUND

Thyroid lymphoma is a relatively rare disease often posing a diagnostic challenge. Reaching the final diagnosis can be delayed if insufficient biopsy material is obtained for immunohistochemistry analysis. The aim of this study was to evaluate the clinical, biochemical, and radiological features of thyroid lymphoma.

METHODS

A retrospective analysis was conducted of all Mayo Clinic patients evaluated between 2000 and 2014 who had a tissue biopsy positive for thyroid lymphoma.

RESULTS

Seventy-five subjects had biopsy-proven thyroid lymphoma, and 62.7% were primary thyroid lymphomas. The median age at diagnosis was 67 years (range 20-90 years). A total of 50.7% were male, and 54.7% had a history of Hashimoto's thyroiditis. Presenting symptoms included neck mass (88%), dysphagia (45.3%), and hoarseness (37.3%). The typical ultrasound appearance consisted of a solid, hypoechoic mass with increased vascularity and variable edge characteristics. Fine-needle aspiration (FNA) biopsies were abnormal in 70.7% of cases, and 42% indicated a specific lymphoma subtype. The diagnosis was confirmed in 53.3% by core biopsy, in 21.3% by thyroidectomy (partial or total), in 12% through incisional biopsy, and in 12% by lymph node biopsy. Core biopsy had a higher sensitivity compared with FNA (93% vs. 71%, p = 0.006).

CONCLUSION

A rapidly enlarging neck mass in the setting of Hashimoto's thyroiditis should raise suspicion for thyroid lymphoma. Radiologically, this usually presents as a large, unilateral, thyroid-centered mass, hypoechoic by ultrasound, and expanding into adjacent soft tissues. Core-needle biopsy should be the first diagnostic test to expedite reaching the final diagnosis and decrease patient burden of additional tests and interventions.

Identification of primary thyroid lymphoma with medical imaging: A case report and review of the literature

Primary thyroid lymphoma (PTL) is a rare thyroid malignancy. Clinical diagnosis of PTL may not be easily established based on imaging studies, as the imaging features of PTL are similar to those of lymphocytic thyroiditis and primary thyroid cancer. The present study describes the case of a patient who was confirmed to have PTL by intra-operative pathological diagnosis. On color Doppler ultrasound, the PTL was shown as a significantly enlarged thyroid with reduced gland echoes. Color Doppler flow imaging showed increased blood flow. By computed tomography, the thyroid was revealed to be enlarged with reduced tissue density, particularly in the left lobe and the isthmus. In addition, calcified spots and swollen lymph nodes were evident. The clinical history of the patient was obtained and the imaging results were retrospectively analyzed. The imaging features of PTL were investigated through reviewing the literature. PTL exhibits specific features on medical imaging that aid in distinguishing it from other thyroid diseases. PTL exhibits specific features on medical imaging that aid in distinguishing PTL from other thyroid diseases, which may aid the support for clinical diagnosis and improve the clinical accuracy.

Imaging findings of thyroidal sarcoma

From 1997 to 2013, 8849 patients with several disorders of the thyroid were treated in our surgical department. In nine patients (0.1%), primary thyroid sarcoma (PTS) was diagnosed. In eight patients, PTS manifested as a thyroid mass (range, 25-90 mm). In one case, a global enlargement of the thyroid was seen. Clinically, all patients presented with neck swelling. On ultrasound, PTS was predominantly hypoechoic. On computed tomography, the sarcomas were hypodense. On magnetic resonance imaging, PTS had inhomogeneous signal increase on T2-weighted images and signal decrease on T1-weighted images with inhomogeneous enhancement.

Familial nonmedullary thyroid carcinoma

BACKGROUND

Nonmedullary thyroid cancers (NMTC) originate from the follicular cells of the thyroid gland and account for over 90% of all thyroid cancers. About 3-10% of the NMTCs are of familial origin, and familial NMTC (FNMTC) is defined as two or more affected first-degree relatives with NMTC in the absence of other known familial syndromes.

SUMMARY

The genes involved in the pathogenesis of FNMTC are yet to be elucidated, although some recent studies identified several predisposition loci with a high degree of genetic heterogeneity. To date, several studies have evaluated the aggressive tumor characteristics associated with FNMTC with conflicting results. Several studies demonstrated that patients with FNMTC have increased rates of multifocal disease, extrathyroidal invasion, and involved lymph nodes compared with sporadic disease. It has been hypothesized that this increased aggressiveness translates into higher recurrence rates and decreased survival of patients with FNMTC.

CONCLUSION

This review highlights clinical aspects and management dilemmas as well as controversial issues in FNMTC. Management recommendations are deduced.

Thyroid lymphoma: recent advances in diagnosis and optimal management strategies

Primary thyroid lymphoma is rare, composing approximately 5% of all thyroid malignancies and less than 3% of all extranodal lymphomas. It typically presents as a rapidly enlarging goiter with associated compressive symptoms. Thyroid ultrasound and fine needle aspiration cytology, using flow cytometry and immunohistochemistry, remain the main modalities used to confirm the presence of lymphoma. The increasing use of an ultrasound-guided core biopsy to achieve an accurate diagnosis has further limited the role of surgery. An open surgical biopsy may still be required not only for definitive diagnosis but also to confirm the subtype of lymphoma. There are limited numbers of randomized or prospective trials to guide management, and controversy remains over optimal treatment. Treatment and prognosis of this disease can be dichotomized into two separate groups: pure mucosa-associated lymphoid tissue (MALT) lymphoma and diffuse large B-cell lymphoma (DLBCL) or mixed subtypes. Early stage (stage IE) intrathyroidal MALT lymphomas typically have an indolent course and may be treated with single-modality surgery, radiotherapy, or a combination of both. DLBCLs are more aggressive, and survival outcomes are highest with multimodal therapy incorporating monoclonal antibodies, chemotherapy, and radiotherapy. The prognosis is generally excellent but can be varied because of the heterogeneous nature of thyroid lymphomas. The aim of this paper is to discuss the changes in diagnostic modalities and to focus on the recent alterations in the management of this rare disease, including targeted therapies as well as the more limited role of the endocrine surgeon.