Case Report: Medullary Thyroid Cancer Workup Initiated by Unexpectedly High Procalcitonin Level-Endocrine Training Saves Life in the COVID-19 Unit

State of Knowledge About Thyroid Cancers in the Era of COVID-19-A Narrative Review

Thyroid cancer (TC), due to its heterogeneous nature, remains a clinical challenge. Many factors can initiate the carcinogenesis process of various types of TC, which complicates diagnosis and treatment. The presented review gathers current information on specific types of TC, taking into account the effects of the COVID-19 pandemic. It is likely that COVID-19 has influenced and continues to influence the function of the thyroid gland. A high percentage of patients with COVID-19 showing simultaneous pathological changes in the thyroid suggests that SARS-CoV-2 may disrupt the function of this gland and initiate pro-oxidative mechanisms, inflammatory states, and autoimmune diseases, thereby promoting the formation of neoplastic changes. Furthermore, changes in the expression of the ACE2, TMPRSS2, CLEC4M and DPP4 genes, observed in TC, also occur in COVID-19. Therefore, it is probable that the interaction of SARS-CoV-2 with thyroid cell receptors may initiate carcinogenesis in this gland. Additionally, some drugs used in TC therapy (e.g., levothyroxine) may increase the affinity of SARS-CoV-2 for cells, which could contribute to a more severe course of COVID-19 and the emergence of long-term symptoms (post-COVID-19). Moreover, the consequences of sanitary restrictions (limited access to medical services, reduction in endocrinological and oncological procedures) that took place in many countries during the COVID-19 pandemic may lead in the future to an increased number of missed diagnoses and the emergence of aggressive cancers.

Deep learning-based cell segmentation for rapid optical cytopathology of thyroid cancer

Fluorescence polarization (Fpol) imaging of methylene blue (MB) is a promising quantitative approach to thyroid cancer detection. Clinical translation of MB Fpol technology requires reduction of the data analysis time that can be achieved via deep learning-based automated cell segmentation with a 2D U-Net convolutional neural network. The model was trained and tested using images of pathologically diverse human thyroid cells and evaluated by comparing the number of cells selected, segmented areas, and Fpol values obtained using automated (AU) and manual (MA) data processing methods. Overall, the model segmented 15.8% more cells than the human operator. Differences in AU and MA segmented cell areas varied between - 55.2 and + 31.0%, whereas differences in Fpol values varied from - 20.7 and + 10.7%. No statistically significant differences between AU and MA derived Fpol data were observed. The largest differences in Fpol values correlated with greatest discrepancies in AU versus MA segmented cell areas. Time required for auto-processing was reduced to 10 s versus one hour required for MA data processing. Implementation of the automated cell analysis makes quantitative fluorescence polarization-based diagnosis clinically feasible.

Advanced medullary thyroid carcinoma uncovered by persistently elevated procalcitonin in a patient with COVID-19

Summary

We report the case of an 88-year-old man hospitalized for COVID-19 with persistently very high procalcitonin (proCt) levels despite infection resolution. Since proCt is an adjunct tumor marker in the diagnosis of medullary thyroid carcinoma (MTC), serum calcitonin (Ct) was also measured showing very high levels. Computed tomography (CT) scan showed the presence of a thyroid mass and neck ultrasound revealed a solid isoechoic, inhomogeneous, 50 mm nodule in the right thyroid lobe, extended into the mediastinum. Fine needle aspiration (FNA) of the thyroid nodule confirmed the diagnosis of MTC. An 18F-fluorodopa positron emission tomography/computed tomography (PET/CT) scan revealed the presence of distant metastases in ribs, vertebrae, in the right iliac wing and the liver. Since surgery was not feasible, the patient was started on cabozantinib 40 mg/dL. After 16 months the patient is still on cabozantinib at the same dose, he reports complete autonomy in daily life activities, and serum Ct is still elevated; however, the imaging evaluation does not show signs of disease progression.

Learning points

High procalcitonin serum values despite the absence of infection are suggestive of MTC. Advanced MTC with multiple metastases can have an indolent course and can go unrecognized for years. Cabozantinib is a valuable option for the treatment of advanced MTC.

What Is the Place of Intermediate Care Unit in Patients with COVID-19? A Single Center Experience

INTRODUCTION

COVID-19 pandemic has led to an increased rate of intensive care unit (ICU) stays. Intermediate care units (IMCUs) are a useful resource for the management of patients with severe COVID-19 that do not require ICU admission. In this research, we aimed to determine survival outcomes and parameters predicting mortality in patients who have been admitted to IMCU.

MATERIALS AND METHODS

Patients who were admitted to IMCU between April 2019 and January 2021 were analyzed retrospectively. Sociodemographics, clinical characteristics, and blood parameters on admission were compared between the patients who died in IMCU and the others. Blood parameters at discharge were compared between survived and deceased individuals. Survival analysis was performed via Kaplan-Meier analysis. Blood parameters predicting mortality were determined by univariate and multivariate Cox regression analysis.

RESULTS

A total of 140 patients were included within the scope of this study. The median age was 72.5 years, and 77 (55%) of them were male and 63 (45%) of them were female. A total of 37 (26.4%) patients deceased in IMCU, and 40 patients (28.5%) were transferred to ICU. Higher platelet count (HR 3.454; 95% CI 1.383-8.625; p=0.008), procalcitonin levels (HR 3.083; 95% CI 1.158-8.206; p=0.024), and lower oxygen saturation (HR 4.121; 95% CI 2.018-8.414; p < 0.001) were associated with an increased risk of mortality in IMCU. At discharge from IMCU, higher procalcitonin levels (HR 2.809; 95% CI 1.216-6.487; p=0.016), lower platelet count (HR 2.269; 95% CI 1.012-5.085; p=0.047), and noninvasive mechanic ventilation requirement (HR 2.363; 95% CI 1.201-4.651; p=0.013) were associated with an increased risk of mortality. Median OS was found as 41 days. The overall survival rate was found 40% while the IMCU survival rate was 73.6%.

CONCLUSIONS

IMCU seems to have a positive effect on survival in patients with severe COVID-19 infection. Close monitoring of these parameters and early intervention may improve survival rates and outcomes.

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.