[Calcitonin determination for early diagnosis of medullary thyroid cancer]

Incidental diagnosis of medullary thyroid carcinoma due to persistently elevated procalcitonin in a patient with COVID-19 pneumonia: A case report

BACKGROUND

Procalcitonin (Pct) is a common biomarker in clinical practice, especially in the era of coronavirus disease 2019 (COVID-19) infection. Although it is frequently used for the diagnosis and prognostication of bacterial infections or sepsis, it is also elevated in a few other conditions, including medullary thyroid carcinoma (MTC).

CASE SUMMARY

A 43-year-old female presented with moderately severe COVID-19 pneumonia in April 2021. She gradually recovered clinically; however, despite normalization of other inflammatory markers, Pct levels remained persistently elevated. Further workup identified the cause as left lobe MTC with locoregional metastasis. Calcitonin levels were high, and carcinoembryonic antigen levels were normal. The patient underwent total thyroidectomy and neck dissection, which was followed by another radical neck dissection due to residual disease. Currently, she is doing well, nearly having completed her course of external beam radiotherapy with no recurrence. Pct is well documented as a screening tool for MTC, especially because of its stable nature compared to calcitonin in the community settings. It is important to keep in mind the differential diagnosis of MTC in patients with persistently elevated Pct levels despite normal levels of other acute phase reactants. To the best of our knowledge, this is the first report from Asia of such an incidental diagnosis of MTC due to persistently elevated Pct levels in a patient with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

CONCLUSION

Persistently elevated Pct levels can occur in any pro-inflammatory state including infections, sepsis, or acute respiratory distress syndrome. In the current setting, SARS-CoV-2 infection is one such clinical scenario, and in rare situations of persistent elevation, MTC may need to be ruled out.

Feasibility of lateral sentinel lymph node biopsy in medullary thyroid cancer: A surrogate tool for determining prophylactic lateral neck dissection-A pilot study

BACKGROUNDS

This study aimed to evaluate usefulness of lateral sentinel lymph node biopsy (SLNB) in determining lateral neck dissection (LND) of patients with medullary thyroid cancer (MTC).

METHODS

Sixteen patients with MTC were enrolled in the study from January 2013 to June 2019. Intratumoral injection of technetium (Tc)-99m phytate followed by lymphoscintigraphy was performed preoperatively. Lateral sentinel lymph nodes were detected by a collimated gamma probe and underwent frozen analysis. Ipsilateral LND was performed in all patients to assess lateral LN status.

RESULTS

The identification rate of sentinel lymph nodes (SLNs) detected by radioisotope was 87.5% (14 of 16 patients). The sensitivity, specificity, positive predictive value, and negative predictive value of frozen analyses were 66.7%, 100%, 100%, and 91.6%, respectively. Based on final histopathology, however, the diagnostic values of lateral SLNB were all 100%.

CONCLUSIONS

This study showed that lateral SLNB can be a promising surgical tool for decisions on LND in patients with MTC.

Preoperative Serum Calcitonin and Its Correlation with Extent of Lymph Node Metastasis in Medullary Thyroid Carcinoma

Simple Summary

Surgery is the only curative treatment for medullary thyroid carcinoma (MTC), but the initial surgical extent is still controversial. We examined whether the preoperative serum calcitonin level reflects the extent of lymph node metastasis (LNM), and therefore might be used to predict the optimal initial surgical extent for MTC. Furthermore, positive and negative likelihood ratios for preoperative serum calcitonin were calculated for calcitonin concentration categories, revealing that serum calcitonin levels can be of diagnostic value and might be applicable to surgical decision-making.

Abstract

The optimal initial surgical extent for medullary thyroid carcinoma (MTC) remains controversial. Previous studies on serum calcitonin are limited to reporting the calcitonin threshold according to anatomical disease burden. Here, we evaluated whether preoperative calcitonin levels can be used to predict optimal surgical extent. We retrospectively reviewed the 170 patients with MTC at a tertiary Korean hospital from 1994 to 2019. We extracted data on preoperative calcitonin level, primary tumor size and the number and location of lymph node metastases (LNMs). To evaluate disease extent, we divided the patients into five groups: no LNM, central LNM, ipsilateral lateral LNM, contralateral lateral LNM, and distant metastasis. We calculated the positive and negative likelihood ratios (LRs) for multiple categories of preoperative calcitonin levels. Preoperative calcitonin level positively correlated with primary tumor size (rho = 0.744, p < 0.001) and LNM number (rho = 0.537, p < 0.001). Preoperative calcitonin thresholds of 20, 200, and 500 pg/mL were associated with the presence of ipsilateral lateral LNM, contralateral lateral LNM, and distant metastasis, respectively. The negative LRs were 0.1 at a preoperative calcitonin cut-off of 100 pg/mL in the central LNM, 0.18 at a cut-off of 300 pg/mL in the ipsilateral lateral LNM, and 0 at a cut-off of 300 pg/mL in the contralateral lateral LNM. The preoperative calcitonin level correlates with disease extent and has diagnostic value for predicting LNM extent. Our results suggest that the preoperative calcitonin level can be used to determine optimal initial surgical extent.

A label-free electrochemical immunosensor based on gold nanoparticles and graphene oxide for the detection of tumor marker calcitonin

A label-free ultrasensitive electrochemical immunosensor has been designed for the detection of calcitonin, a medullary thyroid carcinoma tumor marker.

Endocrine neoplasms in familial syndromes of hyperparathyroidism

Familial syndromes of hyperparathyroidism, including multiple endocrine neoplasia type 1 (MEN1), multiple endocrine neoplasia type 2A (MEN2A), and the hyperparathyroidism-jaw tumor (HPT-JT), comprise 2-5% of primary hyperparathyroidism cases. Familial syndromes of hyperparathyroidism are also associated with a range of endocrine and nonendocrine tumors, including potential malignancies. Complications of the associated neoplasms are the major causes of morbidities and mortalities in these familial syndromes, e.g., parathyroid carcinoma in HPT-JT syndrome; thymic, bronchial, and enteropancreatic neuroendocrine tumors in MEN1; and medullary thyroid cancer and pheochromocytoma in MEN2A. Because of the different underlying mechanisms of neoplasia, these familial tumors may have different characteristics compared with their sporadic counterparts. Large-scale clinical trials are frequently lacking due to the rarity of these diseases. With technological advances and the development of new medications, the natural history, diagnosis, and management of these syndromes are also evolving. In this article, we summarize the recent knowledge on endocrine neoplasms in three familial hyperparathyroidism syndromes, with an emphasis on disease characteristics, molecular pathogenesis, recent developments in biochemical and radiological evaluation, and expert opinions on surgical and medical therapies. Because these familial hyperparathyroidism syndromes are associated with a wide variety of tumors in different organs, this review is focused on those endocrine neoplasms with malignant potential.

[Thyroid C cells and their pathology: Part 2: Medullary thyroid carcinoma]

All tumours with C cell differentiation are designated as medullary carcinomas (MTC). MTC occur sporadically (75-80%) or hereditary (20-25%), the latter being part of the multiple endocrine neoplasia type 2. Familial MTC, which is commonly preceded by "neoplastic" C cell hyperplasia, is caused by autosomal-dominant inherited germ line mutation of the RET-protooncogene; dependent on the codon affected by the mutation, patients show substantially different clinical courses. Due to its morphological heterogeneity, the immunohistochemical demonstration of calcitonin is mandatory for the diagnosis of MTC. For early diagnosis of MTC calcitonin screening has been introduced in Germany and Austria approx. 10 years ago in patients with thyroid nodules; however, an increased calcitonin serum level may also be caused by "non-MEN2-associated" C cell, which is not regarded as a precursor of sporadic MTC. Very rarely tumours may show a mixed C cell-follicular cell differentiation.

Histopathology of C Cells and Medullary Thyroid Carcinoma

The human thyroid gland contains less than 0.01-0.1% calcitonin producing and secreting C cells, which in men are almost exclusively situated in an intrafollicular location; the vast majority of C cells are embryologically derived of remnants of the ultimobranchial body and ultimately of the neural crest, a small subset, however, is presumed to originate from endodermal stem cells. Thyroid tumours with C cell differentiation have been named medullary thyroid carcinoma (MTC); calcitonin is also produced and secreted by MTC which makes this peptide hormone a very useful serum marker both for early detection and clinical follow-up of patients with MTC. About 70-80% of MTC are sporadic tumours, whereas 20-30% are familial MTC which are autosomal-dominant inherited and caused by germline mutations of the RET proto-oncogene located on chromosome 10. This article summarizes the histological, immunhistochemical and molecular genetic features of C cells, C-cell hyperplasia (CCH) and MTC, emphasizing the role of diagnostic pathology.

[Surgical therapy for thyroid gland malignancies]

Surgical therapy for thyroid neoplasms is based on tumor histology and comprises stage-adapted procedures with a high degree of inter-individual variability. This can range from waiting and monitoring, to extensive multivisceral surgery. Grouping together histologically different types of malignancies leads to false assumptions when gauging the radicality of surgery necessary in each particular case. Surgical therapy requires not only an understanding of the biological behavior of the tumor and the risk that it or the therapy poses to the patient, but also knowledge of a wide surgical spectrum of limited and complex resection procedures in the neck and thorax region. The following recommendations are based primarily on the guidelines of the Surgical Working Group for Endocrinology of the German Society for General and Visceral Surgery as well as on the authors' own experience and, where indicated, the guidelines of other working groups.