Absence of anti-rabphilin-3A antibodies in children and young adults with idiopathic central diabetes insipidus: a potential clue to elucidating a tumor etiology.

BACKGROUND: Central diabetes insipidus (CDI) is a rare condition caused by various underlying diseases, including neoplasms, autoimmune diseases, and infiltrative diseases. Differentiating between CDI etiologies is difficult. What has initially been classified as "idiopathic" central diabetes insipidus might in fact underlie various pathogenic mechanisms that are less understood to date and/or are not obvious at initial presentation. Therefore, even if idiopathic CDI is diagnosed at the time of onset, it is common for tumors such as germinoma to develop during surveillance. Crucially, a delayed diagnosis of germinoma may be associated with a worse prognosis. Recently, the presence of anti-rabphilin-3A antibodies has been found to be a highly sensitive and specific marker of lymphocytic infundibuloneurohypophysitis, an autoimmune-mediated CDI. CASE PRESENTATION: We herein present two cases, namely, a 13-year-old boy (patient 1) and a 19-year-old young man (patient 2) who were diagnosed with idiopathic CDI. In both patients, panhypopituitarism developed. Magnetic resonance imaging revealed pituitary stalk thickening and pituitary swelling approximately 1 1/2 years after the onset of CDI. Western blotting did not reveal the presence of anti-rabphilin-3A antibodies in serum in either patient, suggesting that autoimmune mechanisms might not be involved. Both patients were subsequently diagnosed with germinoma on pathological examination. They received chemotherapy, followed by radiation therapy. Notably, testosterone and insulin-like growth factor-1 levels normalized, and libido and beard growth recovered after chemoradiotherapy in patient 2. CONCLUSION: Our data suggest that the absence of anti-rabphilin-3A antibodies in young patients clinically diagnosed with idiopathic CDI may increase the probability of the development of non-lymphocytic lesions, including germinoma. We thus recommend a more attentive approach at the onset of these diseases.

Adrenocortical carcinoma characterized by gynecomastia: A case report.

We present a 4-yr-old boy with adrenocortical carcinoma (ACC), diagnosed due to the appearance of gynecomastia as the presenting symptom. Six months prior to admission, an acute growth spurt along with the development of bilateral breast swelling was observed. He did not present any features of virilization, including enlargement of the testes, increase in testis volume, and penis size. Laboratory investigations showed gonadotropin-independent hypergonadism, with low LH/ FSH levels and elevated estradiol/testosterone levels. Abdominal computed tomography revealed a large heterogeneous mass adjacent to the right kidney and below the liver. Pathological investigations of the biopsy specimen demonstrated that the tumor was an ACC. Pre- and post-operative combination chemotherapy with mitotane was administered and surgical resection was carried out. Post-surgery, the elevated estradiol/testosterone concentrations reverted to within the reference range. Urinary steroid profile and tissue concentration analysis of estradiol and testosterone indicated the presence of estrogen in the ACC tissue. An investigation for TP53 gene aberrations revealed the presence of a germline point mutation in exon 4 (c.215C>G (p.Pro72Arg)). In ACC, the most common symptom is virilization, and feminization, characterized by gynecomastia, is very rare. However, a diagnostic possibility of ACC should be considered when we encounter patients who have developed gynecomastia without the influence of causative factors such as obesity or puberty, and do not present with the typical signs of virilization.

A case report of cutaneous polyarteritis nodosa in siblings.

Cutaneous polyarteritis nodosa (CPAN) is characterized by a necrotizing vasculitis of small and medium-sized arteries in the skin, which can be associated with fever, arthralgia, myalgia, and neuropathy, but, unlike polyarteritis nodosa (PAN), there is no visceral involvement. CPAN is rare in childhood. We report two siblings who developed CPAN during childhood. Interestingly, both had Mediterranean fever gene (MEFV) mutation, i.e. heterozygous E148Q. They also shared HLA-A24, -DR15 alleles. Simultaneous occurrence of MEFV mutation and HLA alleles with CPAN has never been reported in Japan. These cases could provide some hereditary clue for the development of CPAN.

An adolescent case of familial hyperparathyroidism with a germline frameshift mutation of the CDC73 gene.

A 13-yr-old boy who complained of persistent nausea, vomiting and weight loss had hypercalcemia and an elevated intact PTH level. Computed tomography confirmed two tumors in the thyroid gland. The tumors were surgically removed and pathologically confirmed as parathyroid adenoma. Because his maternal aunt and grandmother both had histories of parathyroid tumors, genetic investigation was undertaken for him, and a germline frameshift mutation of the CDC73 gene was identified. CDC73 gene analysis should be done on individuals who are at risk of familial hyperparathyroidism, including those who are asymptomatic, and they should be followed for potential primary hyperparathyroidism and associated disorders including resultant parathyroid carcinoma.

A case of graves' disease diagnosed in the course of bilateral carotid artery stenoses (moyamoya disease); a case report and review of the literature.

A 14-year-old boy was admitted to our hospital after being diagnosed at a local clinic with bilateral carotid artery stenoses (Moyamoya disease) and mild thyrotoxicosis. A blood examination showed suppressed TSH and elevated triiodothyronine and thyroxine levels; however, he was negative for anti-thyrotropin receptor antibody (TRAB) and thyroid stimulating antibody (TSAB). Concern about a possible thyroid crisis led us to administer thiamazole (MMI) and potassium iodide (KI), following which encephalo-duro-arterio-synangiosis (EDAS) of the left side was performed successfully. After about 1 mo, he became positive for TRAB and TSAB. He was thought to have Graves' disease and Moyamoya disease coincidentally. Several factors are considered to be involved in the coincidental onset of these two diseases.

Investigation of iodine deficient state and iodine supplementation in patients with severe motor and intellectual disabilities on long-term total enteral nutrition.

Iodine concentrations of enteral nutrition (EN) formulae available in Japan are very low and long-term total EN (TEN) might result in hypothyroidism due to iodine deficiency (HID). Our aim of this study was to determine the degree of iodine deficiency (ID) and need for iodine supplementation (IS) in patients with severe motor and intellectual disabilities (SMID) on long-term TEN. Thyroid function including urinary iodine concentration (UIC) was monitored, and powdered kelp was provided as a source of iodine supplement. Thirty-five SMID on TEN participated in our study. UIC less than 100 µg /L, representing ID, were detected in 97 % of them. Their TSH ranged from 0.5 to 90 µIU/mL. IS using powdered kelp raised their UIC to the normal range. Thyroid function also recovered in the five hypothyroidism cases, which were diagnosed as HID, was also detected. In Japan, there must be many cases with ID associated with long term TEN. We also discuss the regulation of thyroid function in the iodine deficient state.

Treatment of Hypothyroidism due to Iodine Deficiency Using Daily Powdered Kelp in Patients Receiving Long-term Total Enteral Nutrition.

We investigated thyroid function and urinary iodine concentration (UIC) in seven patients with severe motor intellectual disabilities. All seven received total enteral nutrition (TEN) for more than three years with a daily iodine intake of less than 20 µg. They were diagnosed as hypothyroidism due to iodine deficiency (HID) because of high TSH levels (7.6-82.3 µIU/ml), lower free T4 (FT4 0.4-1.5 ng/dl), negative anti-thyroid antibodies (anti-thyroglobulin antibody, anti-thyroidal peroxidase antibody) and extremely low UIC (<25-58 µg/l) levels. We gave them 1-2 g powdered kelp (200-400 µg as iodine) once a day, which restored their thyroid function and normalized their UICs. We proposed that daily powdered kelp would be effective and safe to treat HID in patient receiving long term TEN.

Characterization of PXK as a protein involved in epidermal growth factor receptor trafficking.

The phox homology (PX) domain is a phosphoinositide-binding module that typically binds phosphatidylinositol 3-phosphate. Out of 47 mammalian proteins containing PX domains, more than 30 are denoted sorting nexins and several of these have been implicated in internalization of cell surface proteins to the endosome, where phosphatidylinositol-3-phosphate is concentrated. Here we investigated a multimodular protein termed PXK, composed of a PX domain, a protein kinase-like domain, and a WASP homology 2 domain. We show that the PX domain of PXK localizes this protein to the endosomal membrane via binding to phosphatidylinositol 3-phosphate. PXK expression in COS7 cells accelerated the ligand-induced internalization and degradation of epidermal growth factor receptors by a mechanism requiring phosphatidylinositol 3-phosphate binding but not involving the WASP homology 2 domain. Conversely, depletion of PXK using RNA interference decreased the rate of epidermal growth factor receptor internalization and degradation. Ubiquitination of epidermal growth factor receptor by the ligand stimulation was enhanced in PXK-expressing cells. These results indicate that PXK plays a critical role in epidermal growth factor receptor trafficking through modulating ligand-induced ubiquitination of the receptor.

The study of cytopathological aspects induced by human cytomegalovirus infection.

In cytological examination, human cytomegalovirus (HCMV) infection can not be implied unless typical HCMV-infected cells like owl's-eye cells are present. However, such cells are not always observed in HCMV-infection cases. The aim of our study is to establish the cytopathological features induced by HCMV. In vitro transfection and fluorescence in situ hybridization (FISH) were performed on human embryo lung (HEL) cells. Marked cellular aggregation was observed at 6-hr postinfection (hpi). Multinucleated cells, giant cells, and, particularly, small vacuoles were present in the nuclei or cytoplasm before the appearance of inclusion bodies. However, molding and ground glass in nuclei were absent. Cell clusters displayed round cytoplasm, dispersed later, and showed anisocytosis. All features occurred before 48 hpi when the owl's-eye cell appeared. In FISH, the positive signal highlighted viral particles that became predominant and localized in nuclei. These cytological aspects are dependent on viral replication and contribute to the cytological detection of HCMV infection.

A case of Epstein-Barr Virus (EBV)-associated thymic carcinoid and investigation of existence of EBV-infected cells in thymus and thymic tumors.

We describe the first case of Epstein-Barr virus (EBV)-associated thymic carcinoid tumor found by in situ hybridization (ISH) on paraffin-embedded sections. ISH revealed that both tumor cells and infiltrated lymphocytes were EBV positive, while a few EBV-infected lymphocytes were detected in 2 of 11 thymuses and 1 of 11 thymomas.