Incidentalomas in the head & neck

Incidental findings (IFs) in the head & neck are a frequent challenge to the reporting radiologist. A combination of complex anatomy, widely varied imaging techniques and the high prevalence of benign pathology, makes safe and appropriate management of head & neck IFs problematic. The non-head & neck radiologist is unlikely to have prior personal experience of the relevant specialties or current involvement with the pertinent multidisciplinary teams, creating unfamiliarity with both the clinical aspects of head & neck disease and the value of examination techniques. This triumvirate of complex anatomy, pathology and imaging creates the perfect environment for excessive investigation and overdiagnosis. In this article, the most frequently encountered and clinically relevant head & neck IFs are summarised. To reflect daily clinical practice, we will firstly consider anatomic abnormalities identified on cross-sectional imaging and ultrasound, followed by a review of PET-CT incidental findings.

Oncocytic nodular hyperplasia of the thyroid

Nodular hyperplasia of the thyroid is a process whereby the gland experiences growth by nodular expansion of thyroid parenchyma. We have encountered 45 patients in whom the process was caused by the growth of well-defined and sharply circumscribed but unencapsulated nodules composed of oncocytic thyroid follicular cells. The lesions arose in 39 women and 6 men, aged 25-69 years (mean = 50.3 years). The surrounding thyroid parenchyma showed features of chronic lymphocytic thyroiditis. The nodules varied from microscopic to 5 cm and appeared to compress the surrounding thyroid parenchyma. Most of the lesions lacked a well-defined capsule. In 26 tumors, the nodules displayed a predominantly follicular pattern of growth; in 8 cases there were admixtures of follicular and trabecular patterns with focal solid areas devoid of follicles. Clinical follow-up in 39 patients ranging from 7 to 22 years (median = 16 years) showed no evidence of recurrence, metastasis, or malignant transformation. One patient died of unknown causes 15 years after the diagnosis, and another patient died 4 years after diagnosis from metastatic colonic adenocarcinoma. Oncocytic nodular hyperplasia is a benign process associated with chronic lymphocytic thyroiditis that should be distinguished from benign and malignant oncocytic (Hurthle cell) tumors of the thyroid.

The Value of Relative Size in the Ultrasound Diagnosis of Follicular Thyroid Neoplasm

Purpose

Ultrasonography as the first choice for thyroid nodules is still difficult to distinguish between solid follicular thyroid neoplasm (FTN) and solid nodular goiter (NG). We tried to investigate the value of relative size (M/S, M: the maximum diameter of target nodule, S: the maximum diameter of the largest of the remaining nodules) that may help to differentiate FTN from NG.

Methods

T test and chi-square test were used to retrospectively analyze the differences of the clinical and ultrasonographic characteristics between FTN and NG in 422 cases in our hospital. T test was used to analyze the difference of M/S value in the two kinds of nodules. ROC was used to evaluate the accuracy of M/S value in distinguishing the two.

Results

There were statistically significant differences in age, echogenicity, calcification, peripheral halo and blood supply between the two. The M/S value is not only significantly different in the two kinds of nodules but also can be used as a quantitative indicator to guide ultrasound diagnosis. ROC analysis showed that the cutoff point and AUC of M/S value were 1.94 and 0.709, respectively.

Conclusion

In the ultrasound diagnosis of multiple thyroid nodules, the M/S value can better distinguish FTN and NG. We need to be aware of FTN when the M/S value of the nodule is greater than 2.

Intratumoral Heterogeneity in Differentiated Thyroid Tumors: An Intriguing Reappraisal in the Era of Personalized Medicine

Differentiated thyroid tumors (DTTs) are characterized by significant molecular variability in both spatial and temporal intra-tumoral heterogeneity (ITH), that could influence the therapeutic management. ITH phenomenon appears to have a relevant role in tumor growth, aggressive behavior and drug resistance. Accordingly, characteristics and consequences of ITH in DTTs should be better analyzed and understood in order to guide clinical practice, improving survival. Consequently, in the present review, we investigated morphological and molecular ITH of DTTs in benign, borderline neoplasms and in malignant entities, summarizing the most significant data. Molecular testing in DTTs documents a high risk for recurrence of cancer associated with BRAF^V600E, RET/PTC 1/3, ALK and NTRK fusions, while the intermediate risk may be related to BRAF^K601E, H/K/N RAS and PAX8/PPARγ. In addition, it may be suggested that tumor genotype is associated with peculiar phenotype.

Digital Versus Optical Diagnosis of Follicular Patterned Thyroid Lesions

OBJECTIVES

To study the concordance between pathologists in the diagnosis of follicular patterned thyroid lesions using both digital and conventional optical settings.

MATERIAL AND METHODS

Five pathologists reviewed 50 hematoxylin and eosin-stained slides of follicular patterned thyroid lesions using both digital (the D-Sight 2.0 scanner and navigator viewer) and conventional optical instruments with washout interval time.

RESULTS

The mean concordance rate with the ground truth (GT) was similar between conventional optical and digital observation (83.2 and 85.2%, respectively). The most frequent reason for diagnostic discordance with GT on both systems was the evaluation of nuclear features (69.1% for conventional optical observation and 59.4% for digital observation). The intraobserver diagnostic concordance mean was 86.8%. Time for digital observation (mean time per case = 2.9 ± 0.8 min) was higher than that for conventional optical observation (mean time per case = 2.0 ± 0.7 min). Interobserver correlation of measurements was higher in the digital observation than the conventional optical observation.

CONCLUSION

Conventional optical and digital observation settings showed a comparable accuracy for the diagnosis of follicular patterned thyroid nodules, as well as substantial intraobserver agreement and a significant improvement in the reproducibility of the measurements that support the use of digital diagnosis in thyroid pathology. The origins underlying the variability of the diagnosis were the same in both conventional optical microscopy and digital pathology systems.

Histopathologic Assessment of Capsular Invasion in Follicular Thyroid Neoplasms-an Observer Variation Study

The assessment of capsular invasion is an essential but challenging step in the diagnosis of encapsulated follicular thyroid neoplasms. Therefore, interobserver agreement in the assessment of capsular invasion in these tumors was investigated among 11 thyroid pathologists by using virtual slides of 20 cases in which the original diagnosis considered the differential diagnosis of definite capsular invasion versus questionable capsular invasion. The assessment of capsular invasion was divided into three categories: (1) non-invasive, (2) questionable invasive, and (3) clear-cut invasive. The interobserver agreements for clear-cut invasive and non-invasive categories were fair (Kappa value = 0.578 and 0.404, respectively), whereas agreement for the questionable invasion was poor (Kappa value = 0.186). Disagreements in the assessment of invasion resulted in variable final pathological diagnoses. For example, the agreement for a diagnosis of malignancy was only fair (Kappa value = 0.545). Moreover, pathologists did not have a uniform approach for rendering a final diagnosis in cases with questionable capsular invasion, though nine of 11 pathologists did use the follicular tumor of uncertain malignant potential diagnosis as proposed by the World Health Organization classification of endocrine organs published in 2017. In conclusion, this study revealed considerable interobserver variation in the evaluation of capsular invasion, especially in follicular neoplasms with questionable invasion.