Somatostatin receptor imaging of thyroid tissue and differentiated thyroid cancer using gallium-68-labeled radiotracers-a review of clinical studies.

INTRODUCTION: The rise in thyroid cancer incidence, especially papillary thyroid cancer (PTC), has underscored the need for improved diagnostic methods and management strategies. Herein, we aim to comprehensively review the evolving landscape in thyroid cancer diagnosis and the potential utility of Gallium-68 (Ga-68) based somatostatin receptor imaging. METHODS: We reviewed the clinical studies involving Ga-68 based radiotracers by looking at the following literature databases -PUBMED, EMBASE, WEB OF SCIENCE and COCHRANE. We employed a detailed search strategy with the following search terms; PubMed: ("gallium Ga 68 dotatate" [Supplementary Concept]) AND ("Thyroid Gland"[Mesh] OR "Thyroid Nodule"[Mesh] OR "Thyroid Neoplasms"[Mesh]), Embase ("gallium 68" AND "Thyroid Disease"), Web of Science: ("Gallium 68 and Thyroid"). RESULTS: A comparison between Ga-68 DOTATATE and Ga-68 DOTANOC showed similar sensitivities but a higher uptake for Ga-68 DOTATATE. Studies comparing Ga-68-based SSTR PET with FDG PET highlighted the potential advantages of both approaches, with Ga-68-based SSTR PET being more specific in certain cases. DISCUSSION: Ga-68-based somatostatin receptor imaging displays clinical utility in RAI-R DTC, offering valuable insight into detecting skeletal lymph node metastases. Notably, it shows potential as a primary imaging tool, potentially augmenting the role of FDG PET. However, SSTR PET imaging's efficacy in distinguishing benign from malignant thyroid nodules varies, with a complex interplay of factors influencing its specificity, indicating its value as an adjunct to existing methods, warranting further research for a refined role in thyroid cancer management. CONCLUSION: Although study variations exist, Ga-based somatostatin receptor imaging holds potential as a complementary tool alongside diagnostic methods in thyroid cancer diagnosis, with particular relevance to RAI-R DTC. In carefully selected patients demonstrating the presence of Ga-68 DOTATATE avid lesions, further exploration, and investigation into the potential utilization of Lu177 DOTATATE are warranted.

RET gene fusion and emergent Selpercatinib resistance in a calcitonin-rich neuroendocrine carcinoma: a case report.

Metastatic lung neuroendocrine carcinomas provide diagnostic challenges in identifying the cell of origin. High level calcitonin expression is not pathognomonic for medullary thyroid cancer. Tumor mutation analysis may provide essential clues regarding tissue origin and treatment targets. Oncogenic RET gene fusions have been identified in non-small cell lung cancer and non-medullary thyroid cancers, whereas RET point mutations are the key genetic finding in both inherited and sporadic MTC. Patients who receive radiation for the treatment of other cancers have an increased risk of developing a second malignancy, including a neuroendocrine carcinoma. Herein, we present a case of calcitonin-rich neuroendocrine carcinoma emerging on a background of prior radiation and chemotherapy for the treatment of Hodgkin's disease. Identification of a RET gene rearrangement (KIF5B-RET) led to initial successful treatment with selpercatinib, with eventual resistance associated with an activating mutation involving the MEK1 protein (MAP2K1 p. E102-I103 del) that led to relapse and progression of the disease.

The effect of hormonal secretion on survival in adrenocortical carcinoma: A multi-center study.

BACKGROUND: Current evidence suggests that cortisol secreting adrenocortical carcinoma has worse prognosis compared to non-secreting adrenocortical carcinoma. However, the effect of other secretory subtypes is unknown. METHODS: This multicenter study within the American-Australian-Asian Adrenal Alliance included adults with adrenocortical carcinoma (1997-2020). We compared overall survival and disease-free survival among cortisol secreting, mixed cortisol/androgen secreting, androgen secreting, and non-secreting adrenocortical carcinoma. RESULTS: Of the 807 patients (mean age 50), 719 included in the secretory subtype analysis: 24.5% were cortisol secreting, 13% androgen secreting, 28% mixed cortisol/androgen, 32.5% non-secreting, and 2% were mineralocorticoid secreting. Median overall survival and disease-free survival for the entire cohort were 60 and 9 months, respectively. Median overall survival was 36 months for cortisol, 30 for mixed, 60 for androgen secreting, and 115 for non-secreting adrenocortical carcinoma, P < .01. Median disease-free survival was 7 months for cortisol, 8 for mixed, 10 for androgen, and 12 for non-secreting adrenocortical carcinoma, P = .06. On multivariable analysis of age, sex, Ki67%, secretory subtype, stage, resection, and adjuvant therapy, predictors of worse overall survival were older age, higher Ki67%, stage IV, mixed secreting, R1, and no adjuvant therapy, P < .05. On subgroup analysis of R0 resection, predictors of worse overall survival included older age and higher Ki67%. Ki67% ≥40, stage III and cortisol secretion were associated with worse disease-free survival. CONCLUSION: Mixed cortisol/androgen secreting adrenocortical carcinoma was associated with worse overall survival, while cortisol or androgen secreting alone were not. Notably, among patients after R0 resection, secretory subtype did not affect overall survival. Cortisol secreting adrenocortical carcinoma demonstrated worse disease-free survival. Ki67% remained a strong predictor of worse overall survival and disease-free survival independent of stage.

A Benign Medullary Thyroid Cancer.

Metastatic dissemination occurs in up to 90% of patients with medullary thyroid cancer (MTC) greater than 4 cm in diameter, and elevated calcitonin levels of more than 500 pg/ml preoperatively have been shown to predict the failure to achieve biochemical remission. Herein, we present a patient with a large tumor and extremely elevated calcitonin level, who was subsequently found to show a "benign" behavior with no evidence of metastasis. The relatively benign behavior of this patient's MTC despite its size and extremely elevated calcitonin levels is thought to be suggestive of certain mutation types in MTC to be more associated with better prognostic outcomes. This case report highlights the value of genetic studies on disease prognostication and the need for comprehensive research studies on genomic profiling in MTC to better understand the relationship of different mutations with prognosis and outcome.

Coexistence of Two Different Thyroid Malignancies: A Collision Phenomenon.

The term "collision tumor" is described as the coexistence of two or more histologically distinct neoplastic morphologies separated by normal tissue in the same organ. Simultaneous papillary thyroid carcinoma (PTC) and follicular thyroid carcinoma (FTC) of the same thyroid lobe is a very rare pathology. Herein, we report a case of PTC and FTC of the same thyroid lobe. A 79-year-old man was evaluated at our hospital for the presence of left hip pain of two-month duration after sustaining a physical trauma to the left side of his body three days prior to admission. X-ray imaging of the left femur revealed a large lytic bony lesion at the proximal end of left femur. Biopsy of the bone lesion was suggestive of FTC. Computed tomography (CT) of the neck revealed an enlarged thyroid with a cystic lesion in the left lobe of the thyroid gland. Total thyroidectomy was performed. Histopathology revealed two separate primary malignancies of PTC and FTC. Genetic studies for RAS gene mutation were negative. He was initiated on suppressive doses of levothyroxine following thyroidectomy. Three months after surgery, thyrotropin alfa stimulated 204.5 mCi I-131 was administered. At seven months of follow-up, the thyroglobulin level was in the lower end of the normal range and anti-thyroglobulin antibody (anti Tg) remained negative (< 1.0 IU/mL). He was doing well and reported no symptoms. For each type of well-differentiated thyroid cancers, several genes have been identified. However, thus far, no specific gene mutation responsible for the pathogenesis of the different tumor types has been described. Management of thyroid collision tumor is usually complex due to the presence of different pathology in the tumor tissues and given the fact that literature on this condition is limited. Typically, the treatment needs to be individualized. Our report brings up a concept that the occurrence is a rare phenomenon of simultaneous mutation of different genes that could give rise to different thyroidal neoplasms.

Rosai-Dorfman Disease and Unusual Local Invasive Presentation.

Rosai-Dorfman disease (RDD) is a rare medical condition with bilateral painless lymphadenopathy. We present the case of a young man diagnosed with a very unique presentation of Rosai-Dorfman disease. A 40-year-old African-American man presented with a firm, non-tender, progressive chest and neck mass appeared three months ago. Imaging of the neck demonstrated an 8.6-cm anterior neck subcutaneous soft tissue mass extending into the anterior mediastinum through the sternum with erosive changes in the sternum and the lesion is abutting the right common carotid artery and innominate vein and surrounds the medial aspect of the clavicles bilaterally. Ultrasound (US)-guided biopsy showed marked polytypic-appearing plasma cell proliferation associated with relatively prominent histiocytes with hemophagocytosis/emperipolesis and focal neutrophils. There were S100+ histiocytes; however, findings were not typical for RDD. As that biopsy was not diagnostic, incisional biopsy with adequate sampling was performed. Surgical pathology demonstrated a very abnormal infiltrate with prominent histiocytes including areas with the features of extranodal RDD. BRAF V600E immunohistochemistry (IHC) was negative. Modified radical neck dissection, proximal sternal resection and superior mediastinal nodal dissection surgery was recommended. However, the patient refused the procedure. Typical manifestations are lymphadenopathy with fever that our patient did not experience. Bone involvement happens in 5-10% of cases. There is not enough data about blood vessel invasion which make our case unique. Treatment plan is still controversial. Clinical monitoring is recommended if the symptoms are tolerable as regression has been reported in many cases (20-50%). Surgery is reserved for patients with vital organ involvement or extra-nodal disease.

Breast enlargement with prednisone treatment.

A 17-year-old boy sought endocrine advice for an unusual gynecomastia that inexplicably recurred whenever he was treated with prednisone. This began at the age of 14, when the patient was diagnosed as having Addison's disease and was first treated with prednisone. An ensuing breast enlargement caused him to stop the medication and a regression of the gynecomastia was observed. Breast enlargement reappeared each time prednisone treatment resumed. Review of this problem led to the final diagnosis of congenital adrenal hyperplasia in a teenager who was genetically female but phenotypically male.