A case of acquired deficiency of pituitary GH, PRL and TSH, associated with type 1 diabetes mellitus

Clinical features of anti-pituitary-specific transcription factor-1 (PIT-1) hypophysitis: a new aspect of paraneoplastic autoimmune condition

The pathogenesis of anti-pituitary-specific transcription factor-1 (PIT-1) hypophysitis was gradually revealed as cases emerged. Our comprehensive analysis, including all reported cases, identified a new instance of anti-PIT-1 hypophysitis postimmune checkpoint inhibitor therapy. All 9 patients exhibited extremely low growth hormone (GH), prolactin (PRL), and thyroid-stimulating hormone (TSH) levels; 2 had a slightly atrophic pituitary gland; 4 had thymoma, and 5 had malignant neoplasms of diffuse large B-cell lymphoma (DLBCL) and other origins. Patients with thymoma showed multiple autoimmune diseases. HLA-A*24:02 and/or A*02:06 were present in six and DR53 in 5 cases analyzed. High anti-PIT-1 antibody titers and ectopic PIT-1 expression in the cytosol and nucleus of the tumor tissues were observed in patients with thymoma or DLBCL, whereas it was exclusively observed in the nuclei of a bladder cancer patient. These findings provide new insights into the pathophysiology of paraneoplastic autoimmune hypophysitis.

Coexisting Prolactin-Secreting Macroadenoma, Hypopituitarism and Type 1 Diabetes Mellitus in a Young Adult Male Patient

The association between type 1 diabetes mellitus (DM) and pituitary prolactinoma is rarely reported in the literature. Herein we present a 23-year-old male patient with co-existing type 1 DM, pituitary macro-prolactinoma and panhypopituitarism secondary to mass effect. The patient presented with generalised symptoms including fatigability, cold hands, decreased insulin requirement secondary to frequent hypoglycaemic episodes two weeks following the diagnosis of type 1 DM. Initial blood workup showed evidence of possible secondary hypothyroidism. The full pituitary profile screen showed profound anterior hypopituitarism with a prolactin level of 67,168 miu/L (normal range 86-324 miu/L). Pituitary MRI showed macroadenoma, 37mm in size, with a suprasellar cystic extension but no chiasmal compression. It was treated medically with cabergoline and a repeat pituitary MRI after eight weeks of initiating treatment showed a 4-mm reduction in the size of the adenoma, and prolactin level decreased to 6,794 miu/L. The case was discussed at the Neurosurgical MDT and the outcome was to continue to monitor while on cabergoline. This case report is the second in the literature, which documented the association between type 1 DM and pituitary prolactinoma in adolescents. These patients might not present with the classical clinical features of hyperprolactinemia, and instead, they present with frequent hypoglycaemia and decreased insulin requirement due to secondary adrenal insufficiency as a consequence of the mass effect of the prolactinoma. Furthermore, non-specific symptoms, such as generalised tiredness and fatiguability, despite reasonable blood sugar control, in young patients with type 1 DM should trigger screening for all anterior pituitary hormones to exclude hypopituitarism.

Hypopituitarism possibly due to lymphocytic hypophysitis in a patient with type 1 diabetes

Hypopituitarism often develops insidiously, and undiagnosed hypopituitarism can influence the glycemic profile of patients with type 1 diabetes. We herein report the case of a 49-year-old man with type 1 diabetes and Hashimoto's thyroiditis who experienced an unexplained improvement in his glycemic level and recurrent severe hypoglycemia, despite a reduction in the dose of insulin. Based on the patient's endocrinological findings, he was diagnosed with hypopituitarism possibly due to lymphocytic hypophysitis, as supported by positive results for human leukocyte antigen A24 and Cw3. Following the administration of hydrocortisone replacement therapy, his insulin requirement increased to a premorbid level, and the severe hypoglycemia resolved.

Genetic and Molecular Basis of QTL of Diabetes in Mouse: Genes and Polymorphisms

A systematic study has been conducted of all available reports in PubMed and OMIM (Online Mendelian Inheritance in Man) to examine the genetic and molecular basis of quantitative genetic loci (QTL) of diabetes with the main focus on genes and polymorphisms. The major question is, What can the QTL tell us? Specifically, we want to know whether those genome regions differ from other regions in terms of genes relevant to diabetes. Which genes are within those QTL regions, and, among them, which genes have already been linked to diabetes? whether more polymorphisms have been associated with diabetes in the QTL regions than in the non-QTL regions.

Our search revealed a total of 9038 genes from 26 type 1 diabetes QTL, which cover 667,096,006 bp of the mouse genomic sequence. On one hand, a large number of candidate genes are in each of these QTL; on the other hand, we found that some obvious candidate genes of QTL have not yet been investigated. Thus, the comprehensive search of candidate genes for known QTL may provide unexpected benefit for identifying QTL genes for diabetes.

A case of myxedema coma caused by isolated thyrotropin stimulating hormone deficiency and Hashimoto's thyroiditis

Myxedema coma (MC) is a rare, but often fatal endocrine emergency. The majority of cases that occur in elderly women with long-standing primary hypothyroidism are caused by particular triggers. Conversely, MC of central origin is extremely rare. Here, we report a case of MC with both central and primary origins. A 56-year-old woman was transferred to our hospital due to loss of consciousness; a chest x-ray demonstrated severe cardiomegaly. Low body temperature, bradycardia, and pericardial effusion suggested the presence of hypothyroidism. Endocrinological examination revealed undetectable levels of serum free thyroxine (T(4)) and free triiodothyronine (T(3)), whereas serum thyroid-stimulating hormone (TSH) levels were not elevated. The woman's serum anti-thyroid peroxidase antibody and anti-thyroglobulin antibody tests were positive, indicating that she had Hashimoto's thyroiditis. Provocative tests to the anterior pituitary revealed that she had TSH and growth hormone (GH) deficiency; however, GH levels were restored after supplementation with levothyroxine for 5 months. This was not only a rare case of MC with TSH deficiency and Hashimoto's thyroiditis; the patient also developed severe osteoporosis and possessed transient elevated levels of serum carcinoembryonic antigen (CEA). This atypical case may suggest the role of anterior pituitary hormone deficiencies, as well as hypothyroidism, in the regulation of bone metabolism.

Adult combined GH, prolactin, and TSH deficiency associated with circulating PIT-1 antibody in humans

The pituitary-specific transcriptional factor-1 (PIT-1, also known as POU1F1), is an essential factor for multiple hormone-secreting cell types. A genetic defect in the PIT-1 gene results in congenital growth hormone (GH), prolactin (PRL), and thyroid-stimulating hormone (TSH) deficiency. Here, we investigated 3 cases of adult-onset combined GH, PRL, and TSH deficiencies and found that the endocrinological phenotype in each was linked to autoimmunity directed against the PIT-1 protein. We detected anti-PIT-1 antibody along with various autoantibodies in the patients' sera. An ELISA-based screening revealed that this antibody was highly specific to the disease and absent in control subjects. Immunohistochemical analysis revealed that PIT-1-, GH-, PRL-, and TSH-positive cells were absent in the pituitary of patient 2, who also had a range of autoimmune endocrinopathies. These clinical manifestations were compatible with the definition of autoimmune polyendocrine syndrome (APS). However, the main manifestations of APS-I--hypoparathyroidism and Candida infection--were not observed and the pituitary abnormalities were obviously different from the hypophysitis associated with APS. These data suggest that these patients define a unique "anti-PIT-1 antibody syndrome," related to APS.

Commentary on "anti-pituitary antibodies in children with newly diagnosed celiac disease: a novel finding contributing to linear growth"

The pathogenesis of celiac disease (CD)-associated short stature is still unclear. The authors showed that newly diagnosed CD patients have a high prevalence of positive antipituitary antibodies that correlates with height impairment. Given the association of CD with other autoimmune disease, these authors' findings show one possible etiology for the poor growth seen in children with CD.

Longitudinal study of patients with idiopathic isolated TSH deficiency: possible progression of pituitary dysfunction in lymphocytic adenohypophysitis

The relationship between isolated TSH deficiency and hypophysitis was studied. Six patients (five women and one man) with idiopathic isolated TSH deficiency were longitudinally investigated with an interval of 31 to 60 months. Clinical symptoms, laboratory results and endocrine function were investigated as well as pituitary magnetic resonance imaging (MRI) at the start and the end of the study. Clinically, initial symptoms due to hypothyroidism were ameliorated by the thyroid hormone replacement in all patients. Oligomenorrhea newly appeared during the study in three patients, although no other symptoms appeared. Serum fT3 and fT4 levels were within the reference ranges, and serum TSH level and its response to TRH stimulation remained low in all patients. Peak plasma GH level during GRH stimulation was significantly (p<0.03) decreased, at the end of the study as compared with the start. Peak plasma FSH level to LHRH stimulation was significantly (p<0.03) decreased as well as basal FSH level. In contrast, peak of prolactin during TRH stimulation was significantly (p<0.03) increased at the end of the study as compared with the start as well as basal prolactin level. Endocrine features at the end of the study were compatible with those of lymphocytic adenohypophysitis (LAH). MRI of the pituitary gland showed empty sella in one patient and slight swelling in two patients. These findings remained unchanged during the study period. One patient underwent pituitary biopsy, with histological examination showing atypical form of LAH. LAH can cause idiopathic isolated TSH deficiency and can functionally progress to combine dysfunction of the pituitary gland.