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The Japanese Society of Thyroid Pathology and the Japan Association of Endocrine Surgeons developed the eighth edition of the General Rules for the Description of Thyroid Cancer (GRDTC) in December 2019. This article describes the pathological diagnosis of the GRDTC, which has been improved through repeated revisions based on the experience of Japanese pathologists and translated into English to introduce the Japanese diagnostic standard to foreign countries. In this edition of the GRDTC, the histopathological classification and descriptions differ in some respects from those of the fourth edition of the World Health Organization (WHO) classification as revised in 2017. For example, the GRDTC does not adopt the concept of borderline lesions (FT-UMP, WDT-UMP, and NIFTP) of the WHO, taking into consideration the popular histological criteria accepted by Japanese pathologists. The cytological reporting system of the GRDTC was partly modified from the Bethesda system in 2015. It has an additional cyst fluid category separated from the unsatisfactory category that has been demonstrated to be useful in Japan. This translated edition makes it easy to submit Japanese clinicopathological studies of thyroid tumors in an international journal. We also wish to contribute to the improvement, standardization, and globalization of the pathological diagnosis of thyroid tumors.

Context: The steroidogenic acute regulatory protein (StAR) is essential for the production of steroid hormones. The mutations in the StAR gene typically cause congenital lipoid adrenal hyperplasia (lipoid CAH), characterized by severe adrenal insufficiency in both sexes and complete female external genitalia in genetic males. Affected 46, XX females feminize at puberty and menstruate but have progressive hypergonadotropic hypogonadism. It has been hypothesized that the cholesterol accumulation in the steroidogenic cells destroys the residual steroidogenic capacity and progressive ovarian failure occurs (two-hit model). Additionally, ovulation and luteinization in the patients is supposed to be impaired. However, those hypotheses have not been confirmed histologically. Objective: We examined whether pathological findings of the ovary in a patient of lipoid CAH corresponded with two-hit model, and whether ovulation and luteinization occurred or not in the patient. Subject: The ovary in an adult 46, XX female with a homozygous nonsense mutation (Q258X) in the StAR gene was examined. When the patient was age 22 yr, the ovary was resected because of enlargement with polycysts and subsequent torsion. Result: The affected ovary demonstrated remarkable lipoid deposition and changes of the mitochondrial ultrastructure. Immunohistochemical examination showed decrease of steroidogenic enzymes such as P450 cholesterol side-chain cleavage (P450scc). Additionally, we detected corpus albicans in the affected ovary. Conclusion: This is the first detailed report on ovarian histology in an adult 46, XX female with a null type mutation of the StAR gene (Q258X), which indicates the evidence of the impairment of ovarian StAR-independent steroidogenesis by lipoid deposition.

Follicular thyroid carcinoma (FTC) usually has a good prognosis unless there is distant metastasis (DM). In this retrospective study we evaluated the outcome of FTC patients with DM and attempted to identify prognostic factors. The subjects of this study were the 106 of FTC patients who underwent thyroidectomy at our hospital between 1989 and 2010 who had been diagnosed with DM at presentation or had developed DM after the initial surgery. Their cumulative cause-specific survival (CSS) rate from diagnosis of DM to date of last follow-up was calculated by the Kaplan-Meier method. Prognostic factors were identified by univariate analysis (the log-rank test) and multivariate analysis (Cox’s proportional hazards model). The site of the DM was the lung in 36 patients, bone in 33 patients, both lung and bone in 28 patients and other sites in 9 patients. During the follow-up period, 22 patients died of their disease. The DMs were treated by radioactive iodine (RI) therapy in 80 patients, by surgical treatment in 36 patients and by external beam radiation therapy (EBRT) in 27 patients. The CSS rates at 5, 10, and 15 years after the first DM was diagnosed were 82.2%, 63.8%, and 23.9%, respectively. Univariate analyses and multivariate analysis identified age at diagnosis of DM and primary tumor size as significant factors related to CSS. In this study, we could not show RI therapy, EBRT or surgical treatment for DM had an impact on the outcome.

The incidence of parathyroid carcinoma is rare. We recently encountered a case of double carcinoma, located in the right and left upper parathyroid glands. A 67-year old man came to the Teikyo University Hospital because of his bilateral parathyroid masses with hypercalcemia and high parathyroid hormone (PTH). Preoperative diagnoses were parathyroid adenoma in the left lobe and papillary thyroid carcinoma or parathyroid carcinoma in the right lobe. First, the left tumor was removed; however, iPTH was still high. The right mass was then resected and iPTH fell to normal range. Histological examination revealed both tumors were parathyroid carcinoma. To the best of our knowledge, this is the first report of double parathyroid carcinoma confirmed histologically.

Medullary thyroid carcinoma (MTC) occurs sporadically or as an inherited disease, with the latter occurring in the form of multiple endocrine neoplasia (MEN) type 2A, MEN type 2B, or familial non-MEN medullary carcinoma (FMTC). MTC is inherited as an autosomal dominant trait and is associated with germline mutations of the RET proto-oncogene. Genetic testing identifies carriers of the mutant gene and enables preventive thyroidectomy. A nationwide questionnaire-based survey was conducted in 1996 and again in 2002, and we report here the results of the two surveys that characterize the clinical course of the inherited form of MTC. The data show a higher rate of inherited MTC than previously described, although MEN2A was found to be the most common inherited form of MTC, the same as in earlier studies. The most important finding was the difference in method of detection of MTC between the two surveys. Since the discovery of the genetic association with the disease, genetic testing has become the diagnostic method of choice, replacing indicators such as neck mass and elevated non-stimulated serum calcitonin level. Genetic testing enables early detection of the disease, which provides patients with the possibility of better outcome.