Introduction For some, chronic lymphocytic thyroiditis (Hashimoto thyroiditis) is an important risk factor for differentiated thyroid cancer (DTC). Surgical cohort studies even suggested a potential role for thyroid peroxidase antibodies (TPO-Abs) on that risk. Our clinical observations argued against that possibility. We designed the present study to evaluate the relationship of TPO-Abs and DTC in a large patient population. Methods We recruited subjects who underwent thyroidectomies at 4 different clinical sites (USA: 1 clinic, 2000-2013 and Greece: 3 clinics, 2007-2021). We gathered data on TPO-Abs titers measured with commercially available chemo- luminescence immunoassays, and reviewed patients’ data including surgical pathology. TPO-Abs ≥ 34 IU/ml was deemed positive (TPO+) and TPO-Abs < 34 IU/ml was deemed negative (TPO-). Odds ratios (OR) for DTC were calculated with Fischer’s exact test and p < 0.05 was deemed significant. Results We reviewed data from 8,461 consecutive thyroid surgery cases. TPO-Abs titers were available for 1,635 subjects: DTC n = 716 (43.8%), benign pathology (BEN) n = 919 (56.2%), TPO + n = 540 (33.0%) and TPO- n = 1095 (67.0%). DTC was found at a lower frequency in TPO + (198/540, 36.7%) compared to TPO- (518/1095, 47.3%) subjects, OR 0.64 (0.52-0.80, p < 0.0001). Rising TPO-Abs titers conferred protection against DTC in a linear fashion: TPO-Abs < 10 IU/ml: 59.3%, TPO-Abs < 34 IU/ml: 47.4%, TPO-Abs 34-100 IU/ml: 42.6%, TPO-Abs 100-500 IU/ml: 32.0%, TPO-Abs > 1000 IU/ml: 19.4%, p < 0.0001. Conclusions Higher TPO-Ab titers appear protective against DTC in our large multicenter cohort of patients who underwent thyroidectomies. Rising preoperative TPO-Abs titers conferred linearly increasing protection against DTC.

Summary Large-cell neuroendocrine carcinoma (LCNEC) is a rare neuroendocrine prostatic malignancy. It usually arises after androgen deprivation therapy (ADT), while de novo cases are even more infrequent, with only six cases described. The patient was a 78-year-old man with no history of ADT who presented with cervical lymphadenopathy. Diagnostic approaches included PET/CT, MRI, CT scans, ultrasonography, biopsies, and cytological and immunohistochemical evaluations. Results showed a poorly differentiated carcinoma in the thyroid gland accompanied by cervical lymph node enlargement. Thyroid surgery revealed LCNEC metastasis to the thyroid gland. Additional metastases were identified in both the adrenal glands. Despite appropriate treatment, the patient died of the disease. De novo LCNEC of the prostate is a rare, highly aggressive tumor with a poor prognosis. It is resistant to most therapeutic agents, has a high metastatic potential, and is usually diagnosed at an advanced stage. Further studies are required to characterize this tumor. Learning points De novo LCNECs of the prostate gland can metastasize almost anywhere in the body, including the thyroid and adrenal glands. LCNECs of the prostate are usually associated with androgen-depriving therapy, but de novo cases are also notable and should be accounted for. Further studies are required to fully understand and treat LCNECs more effectively.

Background Large Cell Neuroendocrine Carcinoma (LCNEC) is the rarest neuroendocrine prostatic malignancy. It usually arises after androgen-deprivation therapy (ADT), while de novo cases are even more infrequent with only 6 cases described to date. Case presentation A 78-year-old man with no history of ADT presented with cervical lymphadenopathy. Diagnostic approach included PET/CT, MRI, and CT scans, U/S, biopsies, cytological and immunohistochemical evaluations. CT revealed a non-enriching region on the right lobe of the thyroid gland. An 18F-FDG PET-CT found increased uptake in the thyroid gland and both adrenal glands. Neck ultrasound identified a right thyroid lobe nodule. A fine needle aspiration of the nodule was performed and cytology was consistent with poorly differentiated carcinoma. A total thyroidectomy with central and bilateral lymph node dissection was performed and the pathology report diagnosed a LCNEC metastatic to the thyroid gland. Additional metastases were identified in both adrenal glands. Despite appropriate treatment, the patient succumbed to his disease. Summary We report the first patient with a de novo purely prostatic LCNEC, metastasizing to the thyroid and the adrenal glands. Conclusions De novo LCNECs of the prostate are very rare, highly aggressive tumors with poor prognosis. They are resistant to most therapeutic agents, have high metastatic potential and are usually diagnosed at an advanced stage. Further studies are needed to characterize these tumors. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m., Saturday, June 11, 2022 1:24 p.m. - 1:29 p.m.

Background Latent autoimmune diabetes in adults is an infrequent form of autoimmune diabetes mellitus, while Hashimoto’s thyroiditis, the most common thyroid disease in adults, rarely manifests as thyrotoxicosis. The concurrent initial presentation of these two autoimmune disorders is extremely rare. Case presentation A 29-year-old male of Albanian descent presented after being hospitalized owing to diabetic ketoacidosis. The diagnosis of type 1 diabetes mellitus was placed, and intensified insulin therapy was initiated. Medical history was not of significance except a 5 kg weight loss within 2 months. The patient presented with recurrent episodes of hypoglycemia, and the doses of preprandial and basal insulin were reduced. The differential diagnosis included type 1 diabetes mellitus “honeymoon” period or another type of diabetes mellitus. His serological tests only revealed positive autoantibodies against glutamic acid decarboxylase 65 and C-peptide. The diagnosis leaned toward latent autoimmune diabetes in adults, and the therapeutic approach involved cessation of preprandial insulin therapy, regulation, and subsequent discontinuation of basal insulin and introduction of metformin. Two years later, basal insulin was reintroduced along with a glucagon-like peptide-receptor agonist and metformin. Further physical examination during the initial visit disclosed upper limb tremor, lid lag, excessive sweating, increased sensitivity to heat, and tachycardia. Laboratory tests were indicative of hashitoxicosis (suppressed level of thyroid-stimulating hormone, high levels of total and free thyroid hormones, positive anti-thyroglobulin and anti-thyroid peroxidase, and negative anti-thyroid-stimulating hormone receptor). Thyroid-stimulating hormone level was spontaneously restored, but an increase was observed during follow-up. Levothyroxine was administrated for 2 years until the patient had normal thyroid function. Conclusions The prevalence of thyroid autoantibodies in patients with latent autoimmune diabetes in adults ranges from 20% to 30%. This correlation can be attributed to genetic involvement as well as disorders of immune tolerance to autoantigens. Hence, this report gives prominence to the holistic approach and consideration of comorbidities in patients with diabetes mellitus.

No abstract