Cytodiagnosis of subacute granulomatous thyroiditis (De Quervain's thyroiditis)-A report of four cases

Subacute granulomatous thyroiditis (SGT)/De Quervain's thyroiditis is a rare self-limiting inflammatory disease, accounting for 3% of all thyroid disorders. Most commonly seen in middle aged women, it shows a characteristic triad of pain in the anterior cervical region, increased ESR and recent history of viral upper respiratory tract infection. The cytomorphological features are not pathognomonic and can also be seen in Hashimoto's thyroiditis, granulomatous infections, sarcoidosis, and papillary thyroid carcinoma. We report four cases of SGT, diagnosed on fine needle aspiration cytology (FNAC). Familiarity with cytomorphology of SGT and awareness of the clinical setting is essential for making an accurate diagnosis.

Granulomatous thyroiditis-A rare case and the diagnostic approach

The presence of well‐formed granulomas, multinucleated giant cells containing colloid, and degenerative changes in thyroid follicular epithelium are the key diagnostic features of granulomatous (subacute, de Quervain's) thyroiditis. Fine needle aspiration cytology is a confirmatory test that is helpful in cases without any clinical suspicion and to exclude differential diagnoses.

A Case of Painless Subacute Thyroiditis Presenting as Fever of Unknown Origin

Subacute thyroiditis (SAT) is characterized by severe pain in the anterior aspect of the neck and tenderness is present during the thyroid gland's palpation. It is commonly caused by viruses including mumps, measles, rubella, coxsackievirus, influenza, and Epstein-Barr virus (EBV). Painless subacute thyroiditis is rare and can present as a fever of unknown origin (FUO). Our case reports an unusual case of SAT as our patient did not have any neck pain. Laboratory investigations show low thyroid-stimulating hormone (TSH), poor or no uptake of radioactive iodine by the thyroid, and elevated erythrocyte sedimentation rate (ESR). Clinicians should be aware that painless SAT can present as a fever of unknown origin.

Can Subacute Thyroiditis Be a Cause of Fever of Unknown Origin?

Subacute thyroiditis (SAT) is a self-limiting, painful, non-suppurative thyroid gland inflammation, which usually develops two to eight weeks after viral upper respiratory tract infections, accompanied by pain and fever. The thyroid gland is large, painful, and tender. It presents with fever, myalgia, arthralgia, weakness, and sore throat.

A 37-year-old male presented to medical ward with a history of fever for three weeks along with swelling of neck and difficulty in swallowing. The patient had features of hyperthyroidism. High-resolution ultrasonography (HRUSG) and thyroid scan were suggestive of thyroiditis. Later on, on follow-up, the patient developed hypothyroidism. He was managed with antibiotics, nonsteroidal anti-inflammatory drugs (NSAIDs), and glucocorticoids, and he responded well to the above treatment. The index patient presented as a case of fever which on workup was found to be secondary to subacute thyroiditis (SAT).

C-reactive protein and thyroid-stimulating hormone levels as risk factors for hypothyroidism in patients with subacute thyroiditis

OBJECTIVE

This study was designed to explore the relationships between the clinical characteristics and outcomes of patients with subacute thyroiditis (SAT).

DESIGN

This is a single-center retrospective study.

PATIENTS

Eighty-nine patients with SAT who were hospitalized in the Sir Run Run Shaw Hospital in Zhejiang, China, from October 2014 to September 2020 were included.

METHODS

The Mann-Whitney U-test, chi-square test, and Cox regression analysis were conducted to identify the relationships between clinical characteristics and outcomes. Receiver operating characteristic (ROC) analysis was performed to determine the optimal cutoff levels of C-reactive protein (CRP) and thyroid-stimulating hormone (TSH).

RESULTS

The hypothyroidism and recurrence rates were 15.7 and 16.9%, respectively. CRP (≥72.0 mg/L), TSH (<0.02 mIU/L), and free triiodothyronine (fT3) (≥4.10 pg/mL) were associated with hypothyroidism. The cutoff level was 97.80 mg/L for CRP (area under the curve (AUC), 0.717, P = 0.014; sensitivity, 57.1%; specificity, 84.0%) and 0.10 mIU/L for TSH (AUC, 0.752, P = 0.004; sensitivity, 100%; specificity, 46.0%) by ROC curve analysis for hypothyroidism. The factors under study were not associated with recurrence.

CONCLUSION

CRP and TSH were risk factors for hypothyroidism in SAT. Thyroid functions should be monitored closely for the early detection of hypothyroidism, especially in patients with CRP levels of more than 97.80 mg/L and TSH levels of less than 0.10 mIU/L.

Subacute (De Quervain) thyroiditis during the COVID-19 pandemic

Coronavirus disease 2019 (COVID‐19) is a new disease whose clinical presentation and potential complications are not yet fully understood. One of these possible reported complications is the onset of subacute (De Quervain) thyroiditis (SAT). Here a series of cases of SAT during the COVID‐19 pandemic are reported, and a possible correlation between these 2 entities is extrapolated.

The Importance of Vitamin D Level in Subacute Thyroiditis Disease and the Effect of Vitamin D on Disease Prognosis

OBJECTIVE

Subacute thyroiditis (SAT) is an inflammatory thyroid disease that manifests with severe pain. The presence of the vitamin D receptor in immune system cells shows that vitamin D deficiency can trigger inflammatory diseases. The aim of the present study was to determine the prevalence of vitamin D deficiency in SAT patients, and the relationship between vitamin D level and permanent hypothyroidism and recurrence rate.

METHODS

In this retrospective study, 25-hydroxyvitamin D (25[OH]D) levels of 170 SAT patients and 86 control subjects were compared.

RESULTS

The 25(OH)D levels were significantly lower in the SAT patients, and there was no seasonal difference. A negative correlation was determined between the erythrocyte sedimentation rate and 25(OH)D, but no significant relationship was found between vitamin D level and prognosis.

CONCLUSION

As a result of this study, it was shown that vitamin D levels in subacute thyroiditis patients were significantly lower than in the healthy control group. Although there is no relationship between vitamin D level and disease prognosis, vitamin D deficiency may increase the rate of respiratory tract infections (especially, influenza, coxsackievirus, measles, adenovirus, retroviruses) and eventually SAT development.

Pitfalls in Thyroid Cytopathology

Fine-needle aspiration (FNA) is among the first diagnostic tools used in the evaluation of thyroid nodules. It has the ability to triage patients with benign and malignant lesions, thus defining the optimum clinical and/or surgical management. The Bethesda System for Reporting Thyroid Cytopathology has found worldwide acceptance. Thyroid FNA offers high positive predictive value (97%-99%), with sensitivities and specificities of 65% to 99% and 72% to 100%, respectively. Nonetheless, many potential diagnostic pitfalls exist that can lead to false-positive and/or false-negative results. This article discusses several of the potential pitfalls in the cytologic evaluation of thyroid lesions.

The prognostic and diagnostic use of hematological parameters in subacute thyroiditis patients

BACKGROUND

Subacute thyroiditis (SAT) is an acute inflammatory disease of the thyroid. Mean platelet volume (MPV), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) values determined from peripheral blood, are accepted as available and practical indicators of systemic inflammation. The purpose of this study was to evaluate the value of hematological parameters in the diagnosis and prognosis of subacute thyroiditis patients.

METHODS

This retrospective study included 306 SAT patients and 102 healthy control subjects. Retrospective analyses were made of age, gender, complete blood counts, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), thyroid function tests, NLR, PLR, and thyroid volume of the patients and the results were compared with the control group.

RESULTS

The mean follow-up time of patients was 29.5 ± 14 months. The ESR, CRP, white blood cell (WBC) count, neutrophil count, hemoglobin, platelet counts, NLR, and PLR were significantly higher in the SAT patients. MPV and lymphocyte count were significantly lower in the SAT patients. The rates of recurrence and permanent hypothyroidism were 15.4% and 9.8%, respectively. The values of ESR, CRP, NLR, PLR, and MPV at the time of diagnosis were not determined to have any effect on recurrence or the development of permanent hypothyroidism.

CONCLUSIONS

The results of this study showed higher PLR and NLR values in SAT patients compared with healthy control subjects, and a lower MPV value. These findings demonstrate that the assessment of hematological parameters in conjunction with radiological and clinical findings will assist in establishing an accurate diagnosis, especially in complicated SAT cases.

Fever of Unknown Origin as a Sole Presentation of Subacute Thyroiditis in an Elderly Patient: A Case Report with Literature Review

An 80-year-old Caucasian male presented with fever of 3-week duration. Outpatient workup for infectious etiologies was negative and due to persistent fever, he was hospitalized for further evaluation of fever of unknown origin (FUO). Physical examination and laboratory studies remained unremarkable; however a follow-up CT scan of chest, abdomen, and pelvis with contrast done to rule out malignancy as an underlying cause of FUO revealed heterogeneous thyroid gland with surrounding hazy changes suggestive of thyroiditis. Thyroid function tests confirmed the diagnosis of subacute thyroiditis. The patient was started on prednisone with good response in his symptoms and was eventually discharged to home. The importance of our case lies in the fact that diagnosing subacute thyroiditis in the absence of classical symptoms of neck pain can be challenging and a physician should have a very high index of suspicion especially in an elderly patient where FUO can be the sole presentation.

Thyroid FNAC: Causes of false-positive results

In this paper, we aim to focus on false positive results in the evaluation of thyroid aspirations, covering cystic, inflammatory, follicular and oncocytic lesions, papillary carcinoma, and medullary carcinoma of thyroid. The recently described entity noninvasive follicular thyroid neoplasm with papillary-like nuclear features is also discussed detailing the impact of its introduction on the sensitivity and specificity of thyroid FNA, as well as the use of molecular tests for diagnostics. Medicolegal issues in relation to current practice in English law are also described.

Asymptomatic thyroiditis presenting as pyrexia of unknown origin: a case report

BACKGROUND

Pyrexia of unknown origin is a difficult and challenging problem for the physician. Endocrine disorders, such as subacute thyroiditis, rarely present with pyrexia of unknown origin. Subacute thyroiditis can have a broad spectrum of clinical presentations including fever and biochemical thyrotoxicosis without overt signs or symptoms.

CASE PRESENTATION

A previously healthy 42-year-old Sri Lankan Sinhalese man was extensively investigated for a prolonged fever of 3 weeks with high inflammatory markers. He had mild tenderness over his neck with cervical lymphadenopathy with no thyrotoxic symptoms or signs. An ultrasound scan revealed an enlarged thyroid with increased vascularity and he had suppressed thyroid-stimulating hormone with elevated free thyroxine and free triiodothyronine hormone levels. Fine-needle aspiration cytology confirmed thyroiditis. He responded well to low-dose steroids.

CONCLUSION

Subacute thyroiditis should be considered in the diagnostic workup of pyrexia of unknown origin even in the absence of overt toxic symptoms of thyroid hormone excess.

Fine-Needle Aspiration of De Quervain's Thyroiditis (Subacute Granulomatous Thyroiditis): A Cytological Review of 20 Cases

INTRODUCTION

De Quervain's Thyroiditis (DQT) is a self limiting inflammatory disease of the thyroid gland that presents with pain and sore throat. Although the diagnosis is usually made clinically, Fine Needle Aspiration (FNA) may provide assistance, particularly in excluding other thyroid lesions.

AIM

The objective of this study was to reveal the cytological characteristics of DQT.

MATERIALS AND METHODS

We retrospectively reviewed the clinical and FNAC findings of 20 cases of DQT to find the most reliable features for a confident cytological diagnosis.

RESULTS

Among the cases reviewed, the common cytological features present in all 20 cases were follicular epithelial cells with degenerative changes and dirty background comprising of cellular debris and mixed inflammatory cells (lymphocytes and macrophages and occasional polymorphs). The next common finding observed was Multinucleated Giant Cells (MNGCs) seen in 19 cases followed by epithelioid cell clusters in 15 and colloid in 13 cases.

CONCLUSION

Presence of follicular epithelial cells, large MNGCs and dirty background of cellular debris, mixed inflammatory cells with predominance of lymphocytes and macrophages were the most striking and consistent features for diagnosis of DQT in cytological smears. The above findings in consideration with the clinical history will help us to reach a definitive diagnosis. FNA also proves to be a useful tool in excluding other thyroid lesions with similar clinical presentations.

Subacute granulomatous (De Quervain's) thyroiditis: Fine-needle aspiration cytology and ultrasonographic characteristics of 21 cases

Background:

Subacute granulomatous thyroiditis (SGT) is an inflammatory disease that presents with different clinical and cytological characteristics. Although the diagnosis is generally made clinically, imaging methods and fine-needle aspiration (FNA) may provide assistance, particularly in atypical cases. The objective of this study is to reveal the ultrasonographic (USG) and cytological characteristics of SGT.

Materials and Methods:

The clinical, USG and cytological findings of 21 cases diagnosed with SGT were reviewed.

Results:

Ultrasonographic data was available in 20 cases. A hypoechoic thyroid nodule with irregular margins was detected in 12 of the 20 total cases. Of these, 9 cases complained about pain in the thyroid lodge and generally had unilateral lesions, heterogeneous and hypoechoic areas with indistinct margins, rather than nodular lesions, which were seen in 7 cases. Cytologically, the multinuclear giant cells (MNGCs) found in all cases were accompanied by a dirty background containing varying numbers of granulomatous structures, including isolated epithelioid histiocytes, proliferated/regenerated follicle epithelium cells and inflammatory cells and colloid.

Conclusion:

Though hypoechoic and heterogeneous areas with irregular margins are strongly associated with thyroiditis, SGT may also appear as painful or painless hypoechoic, solid nodules and generate challenges in differential diagnosis. Although the most remarkable characteristic observed in FNA cytology was the presence of multiple MNGCs with cytoplasm, a dirty background accompanied by mild-moderate cellularity, degenerated-proliferated follicular epithelium cells, rare epithelioid granulomas and mixed type inflammatory cells are characteristic for SGT. The assessment of these radiological and cytological findings in conjunction with clinical findings will assist in the achievement of an accurate diagnosis.