Neuroendocrine tumors presenting with thyroid gland metastasis: a case series

Some uncommon cystic lesions in the anterior head and neck region: Pitfalls to be avoided on cytology

Cystic lesions of the anterior head and neck region are a challenging and frequent finding on cytological smears. The scant amount of cellular material in cystic slides poses the greatest difficulty to interpretation, so that frequently they are diagnosed as inadequate or with minimal cellular component. Despite the majority of cystic lesions being benign, a minor portion consist of malignant cystic entities. In these latter cases, the evidence of very scant malignant cells can be misdiagnosed and/or underestimated, leading to a false negative diagnosis. Many papers have already described and detailed the range of possible benign and malignant cystic lesions in head and neck. In the current review we have focused on the less common entities that often lead to serious misinterpretation.

Neuroendocrine metastasis to the thyroid from unknown primary and extrathyroidal disease response to peptide receptor radionuclide therapy

Neuroendocrine tumor (NET) metastasis to the thyroid is rare, and its presentation as the first manifestation of primary malignancy elsewhere is even more uncommon. We present a case of a 41-year-old female who underwent biopsy of enlarging thyroid nodules with findings suspicious for medullary thyroid cancer (MTC). Subsequent thyroidectomy demonstrated NET of unknown primary in the left lower lobe. Immediate workup with 68Ga-DOTATATE-PET/CT revealed abnormal somatostatin receptor (SR) expressing lesions in the liver, right cervical nodes, thoracic paravertebral soft tissue, precoccygeal soft tissue, and right acetabulum concerning for sites of neuroendocrine malignancy. Due to disease progression while on octreotide injections, a decision was made at the multidisciplinary NET board for the patient to receive peptide receptor radionuclide therapy (PRRT) which includes 4 cycles of 77Lu-DOTATATE (Lutathera). The patient had no side effects nor toxicities during the 8 months of PRRT and achieved a partial treatment response in the early post-treatment scan at 6 weeks. This case illustrates the importance of distinguishing NET metastasis to the thyroid from MTC to ensure appropriate workup and treatment as well as predict the response of neuroendocrine malignancies to PRRT based on the visualized overexpression of SR in the SR-PET scans, despite the organ of origin.

177 Lu-DOTATATE PRRT for Multiple Unusual Metastatic Sites in Neuroendocrine Tumor

ABSTRACT

Thyroid gland and orbit are rare sites of metastases in neuroendocrine tumors. We present an extremely rare case of rectal neuroendocrine tumor with metastases to thyroid gland and intra-orbital regions that demonstrated significant reduction in size and uptake of the lesions on somatostatin receptor based 68 Ga-DOTATATE PET/CT, following 177 Lu-DOTATATE peptide receptor radionuclide therapy. The case illustrates the efficacy of 177 Lu-DOTATATE peptide receptor radionuclide therapy for tumor cytoreduction, which can be considered as a promising treatment modality for somatostatin receptor expressing and tracer-avid metastatic lesions at multiple rare locations.

Neuroendocrine Carcinoma of the Uterine Cervix With Metastases to the Thyroid Gland: A Case Report and Clinical Pathological Review

Thyroid metastasis from a neuroendocrine carcinoma (NEC) is atypical, and the most common site of origin is the lung. We present the case of a 48-year-old lady with a history of NEC in the uterine cervix, classified initially as a p16-positive high-grade endocervical adenocarcinoma with endometrioid differentiation in a cervical biopsy. The patient, after having a thyroid ultrasound due to thyroid nodules, showing a multinodular goiter and suspicious nodules, and a subsequent fine-needle aspiration with a diagnosis of papillary thyroid carcinoma, presented to our hospital for a total thyroidectomy. Histologically, there were metastatic high-grade carcinoma foci within the thyroid, consistent with metastasis from the cervical primary tumor based on the morphology and immunohistochemical stains, the tumor was re-classified as an NEC. The thyroid gland is an uncommon site for metastasis from primary sites, and a very rare site for an NEC origin; besides, this tumor type is infrequent in the uterine cervix and bears an unfavorable prognosis when present. Therefore, when encountering a high-grade metastatic tumor within the thyroid, an NEC has to be considered in the differential diagnosis for a prompt diagnosis and an appropriate treatment.

Metastasis of lung carcinoid in the thyroid gland after 18 years: it is never too late. A case report and review of the literature

Metastasis to the thyroid gland is a rare event. To date, only 11 cases of metastasis from neuroendocrine tumors (NETs) originating in the lung have been reported. We present a case of a patient in his 40s harboring two nodules in the thyroid gland that were diagnosed as well-differentiated NET (G1). Eighteen years before the patient underwent a lung lobectomy of the right upper lobe for a bronchial typical carcinoid with metastasis in one lymph node. Normal blood levels of calcitonin virtually ruled out the diagnosis of medullary thyroid carcinoma (MTC) and supported the diagnosis of a possible thyroid metastasis of the previous bronchial NET. Mutational analysis performed on both primary and metastasis tumor tissue did not show any mutation in the 409 genes analyzed.

Neuroendocrine Tumors of the Thyroid and Their Mimics

This paper will review neuroendocrine lesions of the thyroid and the differential diagnosis with the most significant such tumor of the thyroid, that is, medullary thyroid carcinoma. A brief overview of the understanding of this tumor's identification as a lesion of C cells and its familial and syndromic associations will be presented. Then, a discussion of the various mimics of medullary carcinoma will be given with an approach to the types of tests that can be done to arrive at a correct diagnostic conclusion. This review will focus on practical "tips" for the practicing pathologist.

Diagnostic and Therapeutic Uptake of Intrathyroid Metastasis of Midgut Neuroendocrine Tumor on 68Ga-DOTANOC PET/CT and 177Lu-DOTATATE Imaging

A 58-year-old woman with 5-year history of grade 1 progressive metastatic intestinal neuroendocrine tumor with metachronous liver metastases initially treated by surgery and liver embolization underwent Ga-DOTANOC PET/CT before Lu-DOTATATE therapy. Ga-DOTANOC PET/CT revealed increased uptake in several liver metastases and right iliac lymph nodes, consistent with radiopeptide therapy, including a hypodense isthmic thyroid nodule. Fine needle ultrasound-guided biopsy of the thyroid nodule was realized. Immunohistochemistry was positive for CD56, chromogranin, and synaptophysin and negative for calcitonin, confirming neuroendocrine tumor intrathyroid metastasis. Lu-DOTATATE SPECT/CT showed therapeutic uptake on the thyroid metastasis.

A Calcitonin Non-producing Neuroendocrine Tumor of the Thyroid Gland

Neuroendocrine tumors of the thyroid gland are generally considered to derive from parafollicular endocrine cells (C cells) and are generally referred to as medullary thyroid carcinomas (MTC). Calcitonin secretion is almost always detected in MTC and a prerequisite for both clinical and pathological diagnosis. Thyroid neuroendocrine tumors without any apparent calcitonin secretion reflect a diagnostic dilemma because non-calcitonin-producing MTCs have virtually not been characterized. Here, we report a case of primary thyroid neuroendocrine tumors lacking calcitonin secretion or expression. The tumor cells expressed cytokeratins, chromogranin A, and synaptophysin, all of which were consistent with epithelial and neuroendocrine differentiation. Thyroid transcription factor-1 paired box gene 8, and carcinoembryonic antigen were also immunohistochemically detected, consistent with its thyroid origin. However, the tumor was negative for calcitonin both by immunohistochemistry and in situ hybridization, hence, not meeting the definition of MTC. Despite the loss of calcitonin expression, immunoreactivity for the calcitonin-gene-related peptide was detected in the tumor. Somatic gene mutations of RET, H-RAS, K-RAS, or BRAF were not detected in this case. A limited number of calcitonin non-producing thyroid neuroendocrine tumors are available in the scientific literature available in English, and its etiology and clinical manifestations remain largely unknown. Our case, along with the rare, previously reported cases, suggests that calcitonin non-producing neuroendocrine tumors of the thyroid gland are most likely derived from C cells, but should be differentiated from ordinary MTCs.

Thyroid metastasis from small cell lung carcinoma: a case report and review of the literature

Introduction

Small cell lung carcinoma frequently metastasizes to lymph nodes, liver, adrenal glands, bone, brain and pleura. Metastasis of small cell lung cancer to the thyroid gland is extremely rare.

Case presentation

A 55-year-old Turkish man presented with a mediastinal mass intermingled with mediastinal lymphadenopathy, measuring 11cm in total, and encasing superior vena cava and deviating his trachea, esophagus and vascular structures. He had superior vena cava syndrome. His thyroid appeared normal on computed tomography of his chest. A bronchoscopic biopsy showed small cell lung carcinoma. Chemotherapy with cisplatin and etoposide and external radiotherapy was given. Six months after the presentation, multiple brain metastases were detected on magnetic resonance imaging. Chemotherapy was changed to topotecan and cranial irradiation was performed. At the same time, a right thyroid nodule was detected on computed tomography of his chest and showed growth in size in the following 4 months. A palpable right thyroid nodule came to our attention at that time, the 10th month of presentation. Free thyroxine, free triiodothyronine, thyroid-stimulating hormone, antithyroglobulin and antithyroid peroxidase antibodies were within normal limits. Thyroid ultrasonography showed a right thyroid lobe 26.2×16.8×15.7mm hypoechoic solid nodule with irregular borders. Ultrasonography-guided thyroid fine-needle aspiration biopsy showed metastasis from small cell lung carcinoma. His cranial metastases worsened. He developed right cervical lymph node, hepatic, pancreatic and meningeal metastases and died 15 months after the initial presentation and 9 months after the detection of thyroid metastasis by computed tomography of his chest. Our case and two previously reported cases were male, 55-years old or older and had history of more than 40 pack-years of cigarette smoking. All had metastatic disease elsewhere, when the thyroid metastasis was diagnosed by fine-needle aspiration biopsy. All had poor survival, between 9 and 18 months, after thyroid metastasis was diagnosed.

Conclusions

We conclude that in a patient with a known history of malignant disease, the finding of a new thyroid mass should be promptly evaluated with a thyroid fine-needle aspiration biopsy to search for metastatic disease. The clinical features of our and two previously reported cases were summarized.

Calcitonin-Secreting Neuroendocrine Carcinoma of Larynx with Metastasis to Thyroid

Primary neuroendocrine tumors of the larynx are rare, with moderately differentiated neuroendocrine carcinoma (MDNC) being the most frequent histologic type. We report a MDNC in a 57-year-old gentleman with an enlarging right-sided neck mass. Flexible fiberoptic exam revealed a right arytenoid lesion. Histology from excisional biopsy was concerning for medullary thyroid carcinoma (MTC) versus NET of the larynx. Immunohistochemistry was diffusely positive for calcitonin and CEA and focally positive for TTF-1. Serum calcitonin was elevated. Thyroid ultrasound was unremarkable. The patient underwent laryngectomy, thyroidectomy, and neck dissection. Pathology showed neuroendocrine carcinoma of right arytenoid with positive cervical lymph nodes. A 4 mm deposit of NET was present in right thyroid with adjacent intravascular tumor consistent with thyroidal metastasis from a primary laryngeal NET (MDNC). MDNC and MTC can be microscopically indistinguishable. Both tumors can stain positively for calcitonin and CEA. TTF-1 staining has been useful to help distinguish these tumors as it is strongly and diffusely positive in MTC, but usually negative (or only focally positive) in MDNC. We report the fourth case of primary neuroendocrine carcinoma of the larynx associated with elevated serum calcitonin level and the first such case associated with metastasis to the thyroid.

Calcitonin-negative neuroendocrine tumor of thyroid gland mimicking anaplastic carcinoma: an unusual entity

Medullary thyroid cancer is the neuroendocrine tumor (NET) of thyroid with mostly both secreting calcitonin and immunohistochemically showing calcitonin positivity. Occasionally; NETs of thyroid may have little or no calcitonin expression. We present a case of serum calcitonin negative and immunohistochemically calcitonin-negative staining tumor with positive reaction to neuroendocrine markers synaptophysin and chromogranin-A. The patient's right vocal cord was paralytic and thyroid mass was huge with descending to thorax till hilar region. We discussed diagnostic difficulties and way of treatment about NETs of thyroid with the light of current literature with this case.