A Calcitonin-Negative Neuroendocrine Tumor Derived from Follicular Lesions of the Thyroid

An encapsulated oncoytic neoplasm of follicular origin of thyroid, expressing neuroendocrine markers. A case report and literature review

A case is reported of an oncocytic tumor of the thyroid expressing simultaneously follicular and neuroendocrine markers, but not calcitonin. The data reported in the literature and the possible relationships of these lesions with the calcintonin-negative medullary carcinomas were examined.

Calcitonin-Negative Neuroendocrine Carcinoma of the Thyroid Gland: Case Report and Literature Review

Calcitonin-negative neuroendocrine tumor (CNNET) of the thyroid is an extremely rare entity. In some of the previously reported cases within the literature, the terms “atypical medullary thyroid carcinoma,” “calcitonin-free oat cell carcinoma,” and “a distinct clinical entity” were applied to NETs without definitive evidence of calcitonin production. In the English-language literature, not only are there only few reported cases of CNNET, but the criteria for diagnosis in these cases are also controversial. Most of the current published cases were also treated surgically for local disease. We describe a case of NET of the thyroid with calcitonin, chromogranin A and thyroglobulin negativity, synaptophysin and TTF-1 positivity, and a high Ki-67 proliferation index with metastases in the cervical region as well as mediastinal adenopathies. This case was considered an unresectable thyroid carcinoma, and chemotherapy including cisplatin and etoposide was started as neoadjuvant treatment at the department of medical oncology. Total thyroidectomy plus bilateral and central cervical dissection was performed, and the patient underwent 2 cycles of adjuvant radiotherapy. Currently, the patient's ¹⁸F-FDG-PET/CT findings show a complete response 17 months after diagnosis. In conclusion, CNNET of the thyroid is very rare and there is limited evidence regarding treatment in patients with metastases. Chemotherapy including cisplatin and etoposide as well as early aggressive surgical resection appears to positively impact patients' survival.

Calcitonin-negative neuroendocrine tumor of the thyroid with metastasis to liver-rare presentation of an unusual tumor: A case report and review of literature

BACKGROUND

Neuroendocrine tumors mainly occur in the stomach, intestine, pancreas, and lung and are rarely detected in the thyroid. Thyroid neuroendocrine tumors, designated medullary thyroid carcinoma, generally present with elevated calcitonin. Calcitonin-negative neuroendocrine tumors of the thyroid are extremely rare.

CASE SUMMARY

Here, we present a case report of a 56-year-old female patient with a neck pain complaint. Total thyroidectomy was conducted after comprehensive evaluation, and diagnosis was confirmed as calcitonin-negative neuroendocrine tumor of the thyroid. Two months later, liver metastasis was detected, and transcatheter arterial chemoembolization was subsequently performed to control growth. However, the curative effect was unsatisfactory and multiple intrahepatic metastases occurred after 3 mo.

CONCLUSION

Owing to the rarity of this disease, no clear guidelines are available for treatment. In addition to reporting this rare case, we have reviewed and summarized associated medical literature with an aim to provide a comprehensive reference platform for subsequent research.

Medullary thyroid carcinoma with double negative calcitonin and CEA: a case report and update of literature review

BACKGROUND

Medullary thyroid carcinoma is a malignant uncommon and aggressive tumour of the parafollicular C cells. In about 75% of cases it is sporadic while, in case of RET mutation, it is associated to multiple endocrine neoplasia type 2 (25% of cases). The biochemical features of medullary thyroid carcinoma include the production of calcitonin and carcinoembryogenic antigen. The above-mentioned features are useful in the diagnostic process as well as in the follow up and in the prognostication of the disease. Even if calcitonin elevation is strongly associated to MTC, it can also be found increased in many pathological different conditions as pregnancy, lactation, C-cells hyperplasia, autoimmune thyroiditis, end stage renal disease, lung and prostate cancer and several neuroendocrine tumours. Major medullary thyroid tumours are usually connected to high doses of circulating calcitonin, in fact non-secretory variants have hardly been described.

CASE PRESENTATION

We herein report the case of a 59 years old male, who had undergone total thyroidectomy for multinodular goiter with negative preoperative calcitonin, showing medullary thyroid carcinoma at definitive pathology. To the best of our knowledge, this is the first case documenting a non-secretory medullary thyroid carcinoma, with double negative markers at the time of diagnosis and at the relapse.

CONCLUSION

A Literature review underlining pathological hypothesis, differential diagnosis and alternative and innovative biomarkers to identify non-secretory medullary thyroid carcinoma was carried out.

Calcitonin negative Medullary Thyroid Carcinoma: a challenging diagnosis or a medical dilemma?

BACKGROUND

Medullary thyroid carcinoma is a neuroendocrine tumor belonging form a malignant growth of the thyroid parafollicular C-cells, representing from 1 to 10% of all thyroid cancer. The biochemical activity of medullary thyroid carcinoma includes the production of calcitonin and carcinoembryogenic antigen, which are sensitive tumor markers, facilitating the diagnosis, follow-up and prognostication. The diagnosis is reached through the identification of high basal calcitonin serum level or after pentagastrin stimulation test. Medullary thyroid carcinoma is able to produce other relevant biomarkers as procalcitonin, carcinoembryionic antigen and chromogranin A. In Literature are described few cases of medullary thyroid carcinoma without elevation of serum calcitonin, an extremely rare event. The aim of this study was to analyse the presentation, the main features and therapeutic management of medullary thyroid carcinoma associated with negative serum calcitonin levels.

METHODS

Using the PubMed database, a systematic review of the current Literature was carried out, up to February 2018. Finally, nineteen articles met our inclusion criteria and were selected according to the modified Newcastle-Ottawa scale.

RESULTS

Fourty-nine patients with definitive pathology confirming medullary thyroid carcinoma and with calcitonin serum level in the normal range were identified (24 female, 24 male and not reported gender in 1 case). Mean age was 51.7 years. Serum calcitonin levels were reported for 20 patients with a mean value of 8.66 pg/mL and a range of 0.8-38 pg/mL. Despite the low or undetectable calcitonin serum level, at immunochemistry in almost the half of the cases reported by the Authors, the tumors presented diffuse or focal positivity for calcitonin and carcinoembryionic antigen, while was reported a chromogranin A positivity in 41 of the 43 tested patients.

CONCLUSIONS

Calcitonin negative medullary thyroid carcinoma is an extremely rare pathology. The diagnosis and the surveillance is often challenging and delayed, due to the lack of elevation of serum markers as calcitonin and carcinoembryionic antigen. Further studies are needed, to better define options for management of non secretory medullary thyroid carcinoma and to identify new and reliable biomarkers associated to diagnosis and relapse of this medical dilemma.

Clinical and pathological analysis of 19 cases of medullary thyroid carcinoma without an increase in calcitonin

BACKGROUND

Medullary thyroid carcinoma (MTC), defined as a malignant tumour with C-cell differentiation, is of neuroendocrine origin and is characterized by the synthesis and secretion of calcitonin (CT). MTC without CT secretion has been reported on rare occasions. The purpose of this study was to evaluate the histological, immunohistochemical, and molecular pathologic features as well as the clinical significance of non-secretory MTC (NCR-MTC).

METHODS

A retrospective analysis of patients with NCR-MTC was performed. The clinical features of NCR-MTC, including age, gender, tumour size and number, clinical signs of hypocalcaemia and diarrhoea, and the presence of lymph node metastasis, as well as the pathologic features of the disease, including tumour morphology, presence of neuroendocrine structures, capsular invasion, and immunohistochemical expression and presence of mutations in the RET gene, were evaluated.

RESULTS

Nineteen patients with NCR-MTC were identified among 158 patients with MTC, resulting in a prevalence rate of 12.02%. Patients with NCR-MTC typically had masses less than 1cm in size (73.7%, 14/19). Hypocalcaemia was not present in 94.7% (18/19) of patients. While 42.1% (8/19) of patients with NCR-MTC did not have amyloid deposits, only 18% (25/139) of patients with secretory MTC did not have such deposits. While 95.7% (133/139) of the control group of patients with secretory MTC had neuroendocrine tumour structure, only 84.2% (16/19) of the patients with NCR-MTC had this type of tumour structure. Patients with NCR-MTC were also less likely to have vascular tumour thrombus, lymph node metastasis or thyroid capsular invasion. With regard to immunohistochemistry, CT expression was mostly negative, and carcinoembryonic antigen (CEA) expression was positive in 21.1% (4/19) of patients with NCR-MTC, while only 5.8% (8/139) of patients in the control group had positive CEA expression.

CONCLUSIONS

The prevalence of NCR-MTC was low (12.02%). This type of tumour was smaller in size and more differentiated. Compared with the control group, relatively few patients had obvious symptoms, hypocalcaemia, lymph node metastasis, thyroid capsular or vascular invasion, or tumours with amyloid or neuroendocrine tumour structure.

Calcitonin-negative primary neuroendocrine tumor of the thyroid (nonmedullary) in a dog

The Calcitonin-negative neuroendocrine tumor of the thyroid (CNNET) or “nonmedullary” in humans is a rare tumor that arises primarily in the thyroid gland and may be mistaken for medullary thyroid carcinoma; it is characterized by the immunohistochemical (IHC) expression of neuroendocrine markers and the absence of expression for calcitonin. An Argentine dogo bitch showed a solid, compact thyroid tumor, which was IHC negative for the expression of calcitonin, carcinoembryonic antigen, thyroglobulin and S100 protein, and positive for synaptophysin and cytokeratin AE1-AE3. The Ki-67 proliferation index was low. We cite this case not only because it is the first case report of calcitonin-negative primary neuroendocrine tumor of the thyroid in dogs but also because we want to highlight the diagnostic importance of IHC in this regard.

Calcitonin-Negative Neuroendocrine Tumor of the Thyroid

Neuroendocrine tumors (NETs) of the thyroid are rare; the most common type is medullary thyroid carcinoma (MTC). They are derived from parafollicular cells (C-cells) that usually express calcitonin, chromogranin, and carcinoembryonic antigen. Calcitonin-negative NETs of the thyroid are extremely rare, and the origin of these tumors is unclear. Whereas some believe that these tumors are from follicular cells, recent reports have shown expression of calcitonin gene-related peptide in these tumors, indicating parafollicular C-cell origin. Here, we report a case of calcitonin-negative NET of the thyroid in a 74-year-old woman, with review of the literature.