Melanotic medullary thyroid carcinoma: A case report with review of the literature

International medullary thyroid carcinoma grading system: an Indian tertiary care centre experience

INTRODUCTION

Medullary carcinoma (MTC) is a rare neuroendocrine thyroid neoplasm. The international medullary thyroid carcinoma grading scheme (IMTCGS), which has prognostic significance, has been introduced recently. The present study graded MTC cases using the IMTCGS and evaluated it in our study cohort.

METHODS

All MTC thyroidectomy cases over 6 years were evaluated. Low-grade (LG) and high-grade (HG) were compared. Survival analysis included overall survival (OS), loco-regional free survival and distant metastasis free survival (DMFS).

RESULTS

Of 32 cases, 31.25% were HG and 68.75% LG. The mean age was 44.0 years and M:F ratio 1:1.146. HG patients were older and had tumour cells with high-grade nuclear features and prominent nucleoli and showed distant metastasis. Necrosis was found more in patients with high grade nuclear features. There was discordance between the high Ki67 (60%) and increased mitotic activity (20%). Univariate survival analysis revealed poor DMFRS and OS in the cohorts with high grade, Ki67 > 5% and coagulative necrosis. The multivariate cox regression analysis showed IMTCGS significantly associated with overall survival (HR 28.30, p = 0.009) and DMFS (HR 15.70, p = 0.02).

DISCUSSION AND CONCLUSION

This is the first Indian study evaluating IMTCGS, a very simple and convenient grading system that can be readily used in any tertiary health care centre. IHC for Ki 67 should mandatorily be done irrespective of the low mitotic activity on the HPE and necrosis should be diligently searched in cases with high-grade nuclear morphology. HG MTC cohorts were associated with poor OS as well as DMFRS.

An Aggressive Form of Medullary Thyroid Carcinoma-Melanocytic Subtype: A Case Report

Medullary thyroid cancer (MTC) represents a small proportion of thyroid cancers. In MTC, melanin production is extremely uncommon. Few case reports have documented this rare variant, and follow-up on these cases has been very limited. Our case studies a 51-year-old female who initially presented with goiter. This tumor recurred multiple times despite surgery with rapid growth and poor response to radiotherapy. Microscopic examination showed high-grade malignant neoplasm with lymphocytic differentiation. Immunohistochemical studies were diffusely positive for S100, SOX10, and Melan-A. Histology confirmed melanocytic medullary carcinoma that had undergone a high-grade transformation with loss of epithelial and neuroendocrine expression. Due to the scarcity and rarity of this subtype, further evaluation and case studies are needed for further categorization and prognostication.

Combine with RNA-seq Reveals the Effect of Melatonin in the Synthesis of Melanin in Primary Melanocytes of Silky Fowls Black-Bone Chicken

(1) Background: It was found that the melanin of black-bone chicken has various effects such as scavenging DPPH free radicals and anti-oxidation, and the synthesis of melanin is affected by various factors including hormones. In addition, several studies have found that melatonin affects the melanoma cell synthesis of melanin, which has not been reported in chicken primary melanocytes; so, relevant studies were conducted. (2) Methods: In this study, chicken primary melanocytes were isolated and characterized, and then melanocytes were treated with different concentrations of melatonin to investigate the effects of melatonin on melanin synthesis in chicken melanocytes in terms of melanin synthesis-related genes, melanin content, and tyrosinase activity, and combined with RNA seq to detect the change in gene expression level of chicken melanocytes after melatonin treatment. (3) Results: We isolated and characterized primary melanocytes, and indirect immunofluorescence assay results showed positive melanocyte marker genes. RT-qPCR results showed that melatonin decreased the expression of melanin synthesis-related genes. In addition, melatonin reduced the melanin content and decreased the tyrosinase activity of melanocytes in the treated group. A total of 1703 differentially expressed genes were screened by RNA-seq, and in addition, in the KEGG results, the signaling pathway associated with melanin synthesis, and the mTOR signaling pathway were enriched. (4) Conclusions: Melatonin could decrease the synthesis of melanin in chicken primary melanocytes.