Summary

A 52-year-old female patient with breast cancer presented with a history of fatigue and malaise 1 year prior. She was diagnosed with isolated adrenocorticotropic hormone (ACTH) deficiency (IAD) on endocrinological examination. Her pituitary gland showed normal morphology. Paraneoplastic IAD associated with breast cancer was suspected; however, immunofluorescence staining revealed no ectopic ACTH or proopiomelanocortin expression in the tumor tissue. Subsequently, the patient was diagnosed with idiopathic acquired IAD concurrent with breast cancer, ruling out paraneoplastic syndrome. Although malignancy should be considered a potential cause of IAD, not all patients with concurrent IAD and malignancy necessarily develop paraneoplastic syndrome.

Learning points

• Several adrenal insufficiency symptoms are similar to the nonspecific symptoms associated with malignancies, and therefore, the diagnosis of IAD remains challenging, especially in patients with cancer.

• When we encounter a case of IAD accompanied by a malignant tumor, it is important to suspect that paraneoplastic IAD, a novel clinical condition as secondary hypophysitis, may be the etiologic agent.

• Although malignant tumours should be considered a potential cause of IAD, not all patients with concurrent IAD and malignancy necessarily develop paraneoplastic autoimmune hypophysitis.

Summary

Maturity-onset diabetes of the young (MODY) is a group of monogenic forms of diabetes mellitus characterized by early-onset diabetes with dominant inheritance of beta-cell dysfunction. There are few reports of the coinheritance of glucokinase (GCK) and hepatocyte nuclear factor 1 alpha gene (HNF1A) variants underlying MODY in patients. Herein, we describe a case involving combinations of monoallelic GCK and HNF1A variants associated with MODY. A 10-year-old Japanese girl with a three-generation family history of diabetes without obesity showed high levels of urinary glucose during a school screening test. Her glucose metabolism profile revealed 124 mg/dL of fasting glucose, 6.9% glycated hemoglobin (HbA1c), and 2.78 ng/mL of C-peptide immunoreactivity levels. In a 75-g oral glucose tolerance test, her base glucose, peak glucose, insulin resistance, and homeostasis model assessment of beta cell function levels were 124 mg/dL, 210 mg/dL (120 min), 1.71, and 33%, respectively. Based on the clinical phenotype of GCK-MODY, alimentary and exercise therapy without oral hypoglycemic agents were used to maintain her fasting glucose and HbA1c levels. We explored the coinheritance of MODY with GCK and HNF1A variants in this and past cases and found that careful clinical follow-up is required to firmly establish phenotypic features. Moreover, the accumulation of data on genetically confirmed MODY associated with the coinheritance of GCK and HNF1A variants will be useful for understanding genotype–phenotype correlations.

Learning points

• MODY is a group of monogenic forms of diabetes mellitus characterized by early-onset diabetes with the dominant inheritance of beta-cell dysfunction.

• MODY2 and MODY3 caused by heterozygous loss-of-function variants in the glucokinase (GCK) and hepatocyte nuclear factor 1 alpha (HNF1A) genes, respectively, are the most common forms of the disease.

• Few cases of MODY have previously been reported as being associated with the coinheritance of GCK and HNF1A variants.

• Careful clinical follow-up is required to firmly establish phenotypic features in the coinheritance of MODY with GCK and HNF1A variants.

• The accumulation of data on genetically confirmed MODY associated with the coinheritance of GCK and HNF1A variants will be useful for understanding genotype–phenotype correlations.

Summary

An 89-year-old woman presented with a 6-year history of occasional episodes of impaired consciousness that were relieved by ingestion of a snack. Three months before presenting to our hospital, she had been hospitalized in a local hospital with subdural hematoma caused by a head contusion, where previously unrecognized hypoglycemia was discovered. Fasting plasma glucose concentration was 37 mg/dL, with a relatively high serum level of insulin (34.9 µU/mL). Computed tomography showed a 14 mm hyperenhancing tumor in the tail of the pancreas and she was referred to our hospital for further investigation. A prolonged fasting test revealed the plasma glucose concentration reduced to 43 mg/dL (2.4 mmol/L) at 8 h after the last meal. Serum insulin, proinsulin, and C-peptide concentrations were 21.1 µU/mL, 16.9 pmol/L, and 2.72 ng/mL, respectively. Subsequent intravenous administration of 1 mg of glucagon increased the plasma glucose concentration to 76 mg/dL (4.2 mmol/L). Moreover, the insulin-to-C-peptide molar ratio was 0.14. These data indicated the presence of insulinoma. Interestingly, serum anti-insulin antibodies were elevated (21.1 U/mL), although she had no history of taking exogenous insulin injection, alpha lipoic acid, or sulfhydryl group-containing agents. Human leukocyte antigen (HLA) typing revealed HLA-DRB1*0407 and HLA-DRB1*1405 alleles. Treatment with diazoxide prevented hypoglycemia, but was discontinued due to weight gain and leg edema. Elevated serum anti-insulin antibodies persisted almost 1 year after the diagnosis of insulinoma. We present a rare case of insulinoma concomitant with serum anti-insulin antibodies.

Learning points

• Insulinoma presenting with concomitant anti-insulin antibodies appears rare.

• Insulin/C-peptide molar ratio and serum insulin concentration are useful for differentiating insulinoma and autoimmune syndrome.

• Flash glucose monitoring systems appear suitable for evaluating treatment outcomes.

Summary

An 82-year-old woman with a 60-year history of a lung tumor presented with hypoglycemia. Non-islet cell tumor hypoglycemia (NICTH) was suspected; however, her hypoglycemia stabilized with supplemental food. She was discharged, based on her wishes, and planned to undergo surgery later. After discharge, the hypoglycemia worsened rapidly and required immediate resection. Postoperatively, the hypoglycemia resolved. Western immunoblot analysis confirmed the presence of big insulin-like growth factor 2, confirming NICTH. This patient experienced the rapid progression of symptoms after an unprecedentedly long-term asymptomatic state. Therefore, when NICTH is suspected, early intervention is recommended regardless of the presence of asymptomatic state.

Learning points

• In patients with NICTH, the onset of hypoglycemia is usually within a year of tumor detection, and few reports regarding long-term asymptomatic NICTH have been documented.

• NICTH can cause rapidly progressive symptoms after a long-term asymptomatic state, as in this case, and an asymptomatic state does not preclude the necessity for intervention, especially when patients are at risk for malnutrition.

• Tumor resection is the only curative treatment for patients with NICTH, but there is no consensus regarding the timing of surgery. However, considering the possibility of rapid symptom progression, patients should be examined and treated in a timely manner.

Summary

Functioning gonadotroph tumors are rare neoplasms that can cause ovarian hyperstimulation syndrome (OHSS) in women of reproductive age. Here, we present a case of a follicle-stimulating hormone (FSH)-producing pituitary neuroendocrine tumor (PitNET) with irregular menstrual cycles and OHSS in a Japanese woman. A 34-year-old woman with bilateral multi-cystic ovarian mass was referred to our hospital for ovarian surgery. The imaging feature of magnetic resonance imaging (MRI) of the ovary and elevated estradiol levels with normal FSH and low luteinizing hormone (LH) levels led us to suspect the presence of a functioning gonadotroph PitNET. MRI revealed a 19-mm pituitary tumor, and increased tracer uptake was observed in the pituitary lesion on ¹¹¹In-pentetreotide scintigraphy. Transsphenoidal tumor resection resulted in the resolution of the ovarian enlargement, normalization of her menstrual cycles, and spontaneous pregnancy. Immunohistochemistry (IHC) of the resected tumor for pituitary transcription factors, including steroidogenesis factor 1 (SF1) and estrogen receptor alpha, demonstrated positive immunoreactivity, whereas IHC for pituitary-specific positive transcription factor 1 was negative, suggesting that the tumor belonged to the SF1 lineage of PitNETs (gonadotroph tumor). The tumor cells showed positive expression of FSHβ, while LHβ was mostly negative. Consistent with the high pituitary tumor uptake observed on ¹¹¹In-pentetreotide scintigraphy, the pituitary tumor showed positive expression of somatostatin receptor 2A. Detailed clinical and histological evaluations will provide useful information to understand these rare functioning gonadotroph tumors better.

Learning points

• Functioning gonadotroph tumors are very rare neuroendocrine tumors of pituitary origin.

• Women of reproductive age presenting with bilateral multi-cystic ovarian enlargement, irregular menstrual cycles, and hyperestrogenemia under unsuppressed follicle-stimulating hormone (FSH) levels should be evaluated for FSH-producing tumor.

• Raising awareness of OHSS due to functioning gonadotroph tumors is crucial to prevent unnecessary ovarian surgery.

• Comprehensive histological analysis may provide useful information to better understand the characteristics of functioning gonadotroph tumors.

Summary

Myxoedema coma is a severe form of hypothyroidism with multiple organ dysfunction, characterised by an altered state of consciousness and hypothermia. Intravenous thyroid hormone replacement therapy is the preferred treatment for myxoedema. The mortality rate associated with this disease is high, and early detection and intervention are essential. Supraglottal myxoedema is a rare form of periglottic oedema and can be fatal. A previously healthy 66-year-old man presented with impaired consciousness, hypothermia, and nonpitting oedema. Blood tests revealed the presence of hypothyroidism and respiratory acidosis. He was intubated for type 2 respiratory failure; however, severe laryngeal oedema made the procedure difficult to perform. Oral thyroid hormone therapy was initiated under the diagnosis of myxoedema coma. Tracheostomy was performed because of prolonged type 2 respiratory failure and laryngeal oedema. Three weeks after admission, the patient was weaned off the ventilator. Approximately a week later, laryngeal oedema improved, and the tracheostomy tube was removed. The patient was discharged and remained stable for 3 months. This case report describes a patient with comatose myxoedema and supraglottic oedema who was successfully treated with oral medication alone. This case shows that supraglottic oedema should be considered even in the absence of wheezing or other signs of upper airway obstruction.

Learning points

• Myxoedema coma is a differential diagnosis of respiratory acidosis.

• In myxoedematous coma, the possibility of difficult intubation due to supraglottic oedema should be considered.

• Tracheostomy should be considered for supraglottic myxoedema, which often results in prolonged ventilator use.

• Supraglottic myxoedema can be treated with oral medications.

Summary

IgG4-related disease is a multiorgan disorder in which nodules and hypertrophic lesions are observed simultaneously, or separately, in areas including the pancreas, liver, lungs, salivary glands, thyroid glands, and pituitary glands. IgG4-related hypophysis is one of several IgG4-related diseases and is characterized by pituitary gland and pituitary stalk thickening, various degrees of hypopituitarism, and increased serum IgG4 levels. Steroid therapy is effective for patients with IgG4-related hypophysis, but the reported effectiveness of steroid therapy for restoring pituitary function differs between studies. Following an episode of autoimmune pancreatitis 10 years prior, enlargement of the pituitary gland and stalk along with panhypopituitarism and polyuria developed in a 73-year-old male. A high serum IgG4 level and biopsy of the submandibular gland showing infiltration of IgG4-positive plasma cells led to a clinical diagnosis of IgG4-related hypophysitis. Prednisolone treatment reduced the swelling of the pituitary gland and stalk and improved anterior pituitary function. Although arginine vasopressin secretion remained insufficient, polyuria was relieved and kept in remission even after prednisolone treatment was completed. This is the first reported case in which prednisolone was able to maintain both normal anterior pituitary function and remission of polyuria caused by IgG4-related hypophysitis. IgG4-related hypophysitis has previously been associated with a relapse of symptoms during treatment. However, the patient reported in this case study remained in remission for over 3 months after completion of steroid treatment and should be monitored closely for changes in pituitary function.

Learning points

• Steroid therapy is the first-line therapy for pituitary dysfunction and pituitary stalk swelling in IgG4-related hypophysitis.

• In this case, although posterior pituitary function remained insufficient, polyuria was relieved and kept in remission for over 3 months even after prednisolone treatment was completed.

• IgG4-related hypophysitis has been associated with the relapse of symptoms during steroid tapering, and changes in pituitary function and symptoms should be monitored closely.

• When we encounter cases of adrenal insufficiency and polyuria during observation of autoimmune pancreatitis or other IgG4-related disease, we should consider the possibility of IgG4-related hypophysitis in mind.

Summary

A 73-year-old woman with type 2 diabetes mellitus was referred to our department for glycaemic control. Physical examination revealed two subcutaneous hard masses around the left shoulder and the right hip joint. The patient could not fully extend her fingers because of skin sclerosis in both hands. Laboratory studies showed hyperphosphataemia and a high ratio of renal tubular maximum reabsorption of phosphate to glomerular filtration rate. There were no abnormalities in serum calcium, creatinine, alkaline phosphatase, and intact parathyroid hormone levels, whereas serum fibroblast growth factor 23 was low. Hyperphosphataemic familial tumoural calcinosis/hyperostosis-hyperphosphataemia syndrome (HFTC/HHS) was diagnosed using whole genome sequencing that revealed a novel frameshift beyond the 584th threonine located in the lectin domain of UDP-N-acetyl-alpha-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase 3 associated with a duplication of the 1748th thymine in the coding region of the corresponding gene. Furthermore, anti-nuclear, anti-centromere, and anti-cardiolipin antibodies were positive, implying that comorbid limited type scleroderma might play a role in tumoural calcinosis (TC) development. A low phosphate diet was prescribed with phosphate-lowering medications, including aluminium hydroxide, acetazolamide, and sevelamer hydrochloride. The patient displayed a decrease in serum phosphate levels from 6.5 to 5.5 mg/dL 10 months after the initiation of treatment, but her TC had not improved during treatment for more than 1 year. This case was interesting because the patient with HFTC/HHS exhibited TC despite being over her 60s, and subsequent scleroderma might contribute to the specific clinical course. When HFTC/HHS presents with elderly-onset TC, the involvement of comorbidities in exacerbating TC should be considered.

Learning points

• HFTC/HHS occurs on an autosomal recessive basis, but its clinical course and manifestations differ significantly throughout the cases.

• HFTC/HHS may be undiagnosed until later in life because of its rarity, unfamiliarity, and phenotype diversity; therefore, HFTC/HHS should be included in the differential diagnosis of elderly patients with unexplained hyperphosphataemia or ectopic calcinosis.

• Comorbidities, including rheumatologic disorders, may contribute to developing HFTC/HHS-associated calcinosis.

Summary

Fibromuscular dysplasia can cause renovascular hypertension. Since fibromuscular dysplasia may be underdiagnosed, precise diagnosis and management are crucial, especially for young women. A 20-year-old woman with hypertension and hypokalemia was referred to our hospital for further evaluation of secondary hypertension. At the previous hospital, her blood pressure was 160/110 mmHg and the serum potassium level was 2.9 mEq/L. The equilibrium phase on contrast-enhanced computed tomography revealed a low-density area in the upper median portion of the right kidney. On admission to our hospital, her blood pressure was 141/96 mmHg under 5 mg of amlodipine. Laboratory tests revealed plasma renin activity of 11.3 ng/mL/h and plasma aldosterone concentration of 117.1 pg/mL. Renal venous sampling of active renin concentration showed a right-to-left renin ratio of 3.13, confirming a significant increase in renin secretion from the right kidney. Selective reno-angiography detected focal stenosis with adjacent aneurysmal dilation and tortuosity in the proximal branch of the right renal artery. She was diagnosed with branch artery fibromuscular dysplasia and successfully treated with percutaneous transluminal angioplasty. After the treatment, she was free from hypertension and hypokalemia without any medications. Since branch artery fibromuscular dysplasia is sometimes difficult to diagnose, contrast-enhanced computed tomography can be a promising diagnostic tool as shown in this case. Concerning treatment, our patient was treated with percutaneous transluminal angioplasty, which should be considered for women of reproductive age because recommended antihypertensive medications can be teratogenic even in the first trimester of pregnancy.

Learning points

• Although branch artery fibromuscular dysplasia (FMD) is sometimes difficult to diagnose, it should be considered in patients with high-renin, high-aldosterone hypertension.

• Branch artery FMD can present with a low-density area of the kidney on contrast-enhanced computed tomography, as shown in this case.

• Percutaneous transluminal angioplasty (PTA) can be an appropriate treatment for branch artery FMD, especially in young female patients.

• PTA may immediately improve hypertension and hypokalemia without the need for medications.

Summary

This is a report on antithyroid arthritis syndrome (AAS) which is a rare adverse effect of antithyroid agents. AAS presents with severe symptoms including myalgia, arthralgia, arthritis, fever, and skin eruption due to the use of antithyroid agents. We encountered a 55-year-old woman with severe pain in the hand and forearm and arthralgia in multiple joints, including the knee, ankle, hand, and wrist on day 23 after initiation of methimazole (MMI) for Graves’ disease. Blood tests revealed elevated inflammation markers such as C-reactive protein and interleukin-6, and magnetic resonance imaging of the hands confirmed inflammation findings. After withdrawing MMI on day 25, symptoms showed a tendency toward improvement. Afterwards, inflammation markers also dropped to an almost normal range. In addition to the above findings, the absence of anti-neutrophil cytoplasmic antibodies and most vasculitis symptoms such as nephritis, skin, or pulmonary lesions led to the diagnosis of AAS. A resolution of symptoms, except for mild arthralgia in the second to fourth fingers of the right hand, was observed 61 days after discontinuation of MMI. Although the pathogenesis is unclear, the positive drug lymphocyte stimulation test for MMI and the several weeks before the onset of AAS suggested involvement of a type IV allergic reaction. Based on a discussion of definitive treatment for Graves’ disease, radioactive iodine ablation with ¹³¹I, which was selected by the patient, was performed and improved her thyroid function. Our case demonstrates the importance of awareness regarding AAS, which is a rare and under-recognized, but life-threatening adverse effect of antithyroid agents.

Learning points

• Clinicians should be aware of the possibility of developing antithyroid arthritis syndrome (AAS) in patients treated with antithyroid medications, which can lead to severe migratory polyarthritis.

• Prompt cessation of the antithyroid agent is essential for the resolution of AAS.

• Anti-neutrophil cytoplasmic antibody (ANCA) negativity is needed to differentiate from antithyroid agent-induced ANCA-associated vasculitis, which shows arthritis similar to AAS.