Histone Modification on Parathyroid Tumors: A Review of Epigenetics.

Parathyroid tumors are very prevalent conditions among endocrine tumors, being the second most common behind thyroid tumors. Secondary hyperplasia can occur beyond benign and malignant neoplasia in parathyroid glands. Adenomas are the leading cause of hyperparathyroidism, while carcinomas represent less than 1% of the cases. Tumor suppressor gene mutations such as MEN1 and CDC73 were demonstrated to be involved in tumor development in both familiar and sporadic types; however, the epigenetic features of the parathyroid tumors are still a little-explored subject. We present a review of epigenetic mechanisms related to parathyroid tumors, emphasizing advances in histone modification and its perspective of becoming a promising area in parathyroid tumor research.

Analysis of the role of thyroidectomy and thymectomy in the surgical treatment of secondary hyperparathyroidism.

PURPOSE: Parathyroidectomy can be subtotal or total with an autograft for the treatment of renal hyperparathyroidism. In both cases, it may be extended with bilateral thymectomy and total or partial thyroidectomy. Thymectomy may be recommended in combination with parathyroidectomy in order to prevent mediastinal recurrence. Also, the occurrence of thyroid disease observed in patients with hyperparathyroidism is poorly understood and the incidence of cancer is controversial. The aim of the present study was to report the experience of a single center in the surgical treatment of renal hyperparathyroidism and to analyse the role of thyroid and thymus surgery in association with parathyroidectomy. MATERIALS AND METHODS: We analysed parathyroid surgery data, considering patient demographics, such as age and gender, and surgical procedure data, such as type of hyperparathyroidism, associated thyroid or thymus surgery, surgical duration and mediastinal recurrence. Histopathological results of thyroid and thymus samples were also analysed. RESULTS: Medical records of 109 patients who underwent parathyroidectomy for secondary hyperparathyroidism were reviewed. On average, thymectomy did not have impact on time of parathyroidectomy (p = 0.62) even when thyroidectomy was included (p = 0.91). Intrathymic parathyroids were detected in 7.5% of the thymuses removed and papillary carcinoma was detected in 20,8% of thyroid tissue samples. Two patients showed recurrence of supernumerary intrathymic parathyroids and a single case of mediastinitis was observed. CONCLUSIONS: Parathyroidectomy with thymectomy and/or thyroidectomy has an important role in the treatment of renal hyperparathyroidism since thyroid cancer can frequently occur and require surgery. Thymectomy should be considered to avoid recurrence and a risky re-operation.

Optical coherence tomography imaging during thyroid and parathyroid surgery: a novel system of tissue identification and differentiation to obviate tissue resection and frozen section.

BACKGROUND: Optical coherence tomography (OCT) allows tissue histologic-like evaluation, but without tissue fixation or staining. We investigated OCT images from tissues obtained at thyroid and parathyroid surgeries to provide a preliminary assessment as to whether these images contain sufficient information for recognition and differentiation of normal neck tissues. METHODS: Normal tissues were obtained from patients undergoing surgical treatment. Two new-generation OCT systems, including optical frequency domain imaging (OFDI) and µOCT, were compared to representative hematoxylin-eosin histology. RESULTS: Thyroid, fat, muscle, lymph nodes, and parathyroid tissues were evaluated. Histologic-like microscopic characteristics sufficient for tissue type identification was realized using both systems for all tissue types examined. CONCLUSION: This pilot study demonstrated that new-generation OCT systems are capable of recognizing and differentiating neck tissues encountered during thyroid and parathyroid surgeries. Further advances in OCT miniaturization and development of sterile intraoperative probe formats may allow OCT to offer an intraoperative "optical biopsy" without fixation, staining, or tissue resection.