Cystic Thyroid Nodules: Diagnostic and Therapeutic Dilemmas:

Thyroid "claw sign" a useful diagnostic marker in the outsized lesions of isthmus: A large colloid cyst

Thyroid isthmus lesions are generally small sized and can be solid or cystic. Discerning isthmic origin of a large nodule, especially if purely cystic, can become a diagnostic challenge because of thin thyroid tissue in it. We report a case of a 68-year-old male patient who had 6 weeks history of non- inflammatory central neck swelling associated with recent dysphagia, for which he underwent ultrasound and computed tomography (CT) scan examinations. Colloid nodules usually do not require further attention. Despite being commonest and benign thyroid nodules, they may require treatment if causing pressure symptoms. Its imaging characteristics can be variable, but they usually exhibit comet tail artifacts on ultrasound. In equivocal cases, claw sign on CT scan is diagnostic to confirm the site. Radiologists have a principle role to rule out other differentials of cystic neck lesions by careful examination of imaging features. In our case, CT scan allowed to rule out primary differential of thyroglossal cyst and guided clinicians for specific management plan.

Thyroid Cysts in Cats: A Retrospective Study of 40 Cases

Background

Thyroid cysts are rare in cats and poorly documented.

Objectives

To report distinguishing clinical features and treatment responses of cats with thyroid cysts.

Animals

Forty client‐owned cats.

Methods

Retrospective review of medical records for cats with thyroid cysts confirmed by scintigraphy, ultrasound, magnetic resonance imaging, or necropsy at 4 referral centers between 2005 and 2016. Signalment, clinical findings, diagnostic testing, treatment, and outcome were recorded.

Results

Cats ranged in age from 8 to 20 years with no apparent breed or sex predilection. 37 of 40 (93%) cats were hyperthyroid (duration, 1–96 months). Clinical findings included palpable neck mass (40/40, 100%), weight loss (15/40, 38%), dysphagia (8/40, 20%), decreased appetite (5/40, 13%), and dyspnea (4/40, 10%). Cysts were classified as small (≤8 cm³) in 16 (40%) and large (>8 cm³) in 24 (60%) cats. Of 25 cats treated with radioiodine, hyperthyroidism resolved in 23 (92%), whereas thyroid cysts resolved in 12 (50%). Radioiodine treatment resolved small cysts in 8 of 13 (62%) cats and large cysts in 4 of 11 (36%) cats. Eight cats, including 2 euthyroid cats, underwent thyroid‐cystectomy; 3 with bilateral thyroid involvement were euthanized postoperatively for hypocalcemia. Excised cystic thyroid masses were identified as cystadenoma (4) and carcinoma (4).

Conclusions and Clinical Importance

Thyroid cysts are encountered in hyperthyroid and euthyroid cats with benign and malignant thyroid tumors. Radioiodine treatment alone inconsistently resolved thyroid cysts. Thyroid‐cystectomy could be considered in cats with unilateral thyroid disease or when symptomatic cysts persist despite successful radioiodine treatment of hyperthyroidism.

Thyroid Ultrasound-Guided Fine-Needle Aspiration: The Positive Influence of On-Site Adequacy Assessment and Number of Needle Passes on Diagnostic Cytology Rate

OBJECTIVE

Nondiagnostic cytology is the most important limitation of thyroid ultrasound-guided fine-needle aspiration (US-FNA). This study aimed to identify factors associated with the adequacy rate of thyroid US-FNA.

STUDY DESIGN

Consecutive thyroid US-FNAs (2006-2013) were retrospectively included. Attending radiologists, radiology fellows and radiology residents performed US-FNA, usually involving 2-3 needle passes. In more recent years, rapid on-site adequacy assessment (ROSAA) was performed to ensure specimen adequacy. US characteristics, procedural variations and cytology results were extracted from US and pathology reports and statistically evaluated.

RESULTS

Diagnostic cytology was obtained in 64.6% of 1,381 thyroid US-FNAs. Factors associated with nondiagnostic cytology were ROSAA (74.6% diagnostic cytology, OR 0.55, 95% CI 0.42-0.71), ≥3 clinic visits for US-FNA of the same thyroid nodule (54.7%, OR 1.56, 95% CI 1.16-2.10) and increased intranodular vascularization (51.8%, OR 1.73, 95% CI 1.17-2.57). With ROSAA, an increasing number of needle passes demonstrated improving adequacy rates. The adequacy rate was not operator-dependent.

CONCLUSION

This study demonstrates that ROSAA improves the adequacy rate of thyroid US-FNA. Without ROSAA, we recommend performing at least 3 needle passes. Less diagnostic cytology is obtained from nodules with increased intranodular vascularization or from those undergoing US-FNA ≥3 times.

Rapid onsite evaluation improves the adequacy of fine-needle aspiration for thyroid lesions: a systematic review and meta-analysis

BACKGROUND

Fine-needle aspiration (FNA) with ultrasonography guidance is one of the optimal techniques for the diagnostic evaluation of thyroid nodules. A significant subset of thyroid FNAs continues to be inadequate for interpretation, which potentially leads to increased costs from repeat aspirations. Numerous studies have been published regarding the influence of rapid onsite evaluation (ROSE) by cytopathologists on thyroid FNAs, some indicating that FNA is more likely to be adequate for interpretation with ROSE, while others refute this idea. To our knowledge, no meta-analysis of the literature on this subject has been undertaken.

METHODS

We searched MEDLINE and EMBASE using the following search string: (needle biopsy) AND (assessment or onsite OR onsite or immediate or rapid)/title or abstract. There were no restrictions on study design, language, anatomic site, or time period. Only studies comparing two arms (with/without ROSE) at a single site were eligible for inclusion. Potentially relevant studies were subjected to a citation search (forward search) and reference search (backward search) using SCOPUS. Statistical calculations were performed using Stata Release 12. Meta-analysis was completed using a random-effect model as implemented in the metan routine in Stata.

RESULTS

An initial search obtained 2179 studies from MEDLINE and EMBASE, and screening yielded 71 potentially relevant studies. A focused review of this subset resulted in seven full studies and one abstract that met our inclusion criteria. Our citation search using SCOPUS yielded no new studies. Overall, the average adequacy rate was 83% without ROSE compared to 92% with ROSE. Visual inspection of the data suggested that the improvement in adequacy due to ROSE may be related to the adequacy rate without ROSE. Metaregression analysis showed that the change in the adequacy rate was strongly correlated (t=-12.7, p<0.001) with the non-ROSE adequacy rate. In addition, the non-ROSE adequacy rate explained all, but 10% of the residual between study variability in the change in the adequacy rates due to ROSE.

CONCLUSIONS

ROSE is generally associated with an improvement in adequacy, but the impact of ROSE depends heavily on the initial adequacy rate. Sites with lower initial adequacy rates can benefit the most from the implementation of ROSE.

Management of well-differentiated thyroglossal remnant thyroid carcinoma: time to close the debate? Report of five new cases and proposal of a definitive algorithm for treatment

BACKGROUND

Thyroid carcinoma is diagnosed in approximately 1% to 2% of thyroglossal duct remnants (TGDR). No definite agreement exists concerning the management of TGDR carcinoma, especially regarding the role of total thyroidectomy and postoperative adjuvant therapy. We report five new cases of TGDR carcinoma and review relevant articles in an attempt to clarify this issue.

METHODS

We studied the demographic, clinical, tumor-related, treatment, pathologic, and outcome data on five patients treated at our institution for a TGDR carcinoma and compared the results with the four most important series published.

RESULTS

All five patients were women, and diagnosis occurred after surgery in four. The sizes of the papillary tumors were 40, 38, 25, 23, and 15 mm (mean, 28.2 mm; range, 15-40 mm). Fine-needle aspiration biopsy of the TGDR had a low sensitivity (positive for one in four). A Sistrunk procedure was performed for resection of the TGDR in four patients, and plain TGDR resection was performed for the other patient. Three patients underwent repeat surgery; total thyroidectomy was performed in all cases, and cervical bilateral node dissection was performed in one case. With a median follow-up of 123.8 months (range, 8-284 months), all the patients are alive and free of disease, with no recurrences.

CONCLUSIONS

TGDR carcinoma is a rare malignant tumor that is usually diagnosed after surgery; papillary carcinoma is the most common type. The currently recommended treatment is a Sistrunk procedure, with a tendency to deferred total thyroidectomy in selected cases (similar criteria exist for papillary carcinoma of the thyroid gland). The prognosis is excellent, with a good long-term survival.

The impact of assessing specimen adequacy and number of needle passes for fine-needle aspiration biopsy of thyroid nodules

Fine-needle aspiration biopsy (FNAB) of thyroid nodules is a safe, cost-effective procedure but the rates of inadequate cytology specimens range from approximately 1% to 15%. This study tests the hypothesis that ultrasonographically (US) guided FNAB and onsite assessment of cytology improves the adequacy rate of FNAB. A retrospective analysis was performed on 693 thyroid FNAB specimens obtained with and without ultrasound guidance and with or without onsite cytology assessment. Overall, 29 specimens (4%) were inadequate for diagnosis. Among 163 cystic nodules and 530 solid nodules, inadequacy rates were 15% (n = 24) and 1% (n = 5) respectively (p = 0.0001). An onsite assessment of cytology for adequacy was done in 550 cases (83%), which was more accurately performed by a cytopathologist (97%) than a cytotechnologist (93%, p = 0.015). With US-guided FNAB, 3% of the cytology specimens were inadequate, compared to a 7% rate when US was not done (p = 0.003). The mean number of needle punctures necessary for an adequate specimen was 3.8 +/- 0.06 (median, 3.0; range, 1-11), which was different among various types of doctors, ranging from 3.2 +/- 0.07 to 5.4 +/- 0.12 (p = 0.001 analysis of variance [ANOVA]). The fewest number of needle passes to achieve an adequate specimen were required by university endocrinologists and pathologists working together (average, 3.2 +/- 0.07; median, 3.0; range, 1-11). Sample inadequacy rate varied significantly among physician groups, ranging from 3% to 18% (p = 0.0001 ANOVA). Stepwise regression analysis showed that onsite assessment of cytology, US-guided FNAB (p = 0.16), and cystic nature of the nodule (p < 0.0001 for all) correlated with adequacy of the specimen. We conclude that US-guided FNAB with onsite evaluation of cytology specimens substantially increases the adequacy of cytology specimens and decreases the number of required needle passes, which ultimately reduces patient discomfort and diagnostic errors, thus raising the question as to whether this should eventually become the standard of care. We believe this is a goal that training programs should strive to achieve.