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

Menstrual cycle abnormalities are common in premenopausal females with Cushing’s syndrome, although the underlying mechanism is poorly understood. Signs and symptoms found in Cushing’s syndrome overlap with polycystic ovarian syndrome (PCOS). The patient is a 33-year-old female previously diagnosed by a gynecologist with PCOS and treated with oral contraceptive pills (OCPs) for 2 years. She then discontinued her OCPs without consulting a clinician, resulting in amenorrhea for 6 months, for which she presented. She also had symptoms of depression and anxiety but had no other signs and symptoms of Cushing’s syndrome, except a plethoric face. Initial lab work showed evidence of central hypogonadism (low luteinizing hormone, follicle-stimulating hormone, and estrogen), so a complete anterior pituitary hormone workup was done. Her thyroid-stimulating hormone was also low with a low free T4 level. Prolactin level was normal, but surprisingly, her AM cortisol level was high. The Cushing’s syndrome workup revealed non-suppressed cortisol after a 1 mg dexamethasone suppression test and positive 24-h urine cortisol with suppressed adrenocorticotrophic hormone. A CT scan of her adrenal glands revealed a left adrenal adenoma. She underwent a left adrenalectomy, after which her menstrual cycles became regular again, and pituitary function has recovered.

Learning points

• In Cushing's syndrome, female patients can have menstrual abnormalities due to the high cortisol levels, which can affect gonadotrophin levels.

• We encourage clinicians to include Cushing's syndrome in the differential diagnosis of patients with central hypogonadism.

Summary

ACTH-secreting pituitary adenomas causing Cushing’s disease (CD) typically present with weight gain, whereas weight loss and hypokalemia in endogenous Cushing’s patients are suggestive of ectopic ACTH production. We report a case of CD presenting with atypical features of marked weight loss and hypokalemia. A 75-year-old female was admitted to the hospital with a history of profound weight loss, associated with uncontrolled hypertension, hyperglycemia, severe proximal muscle weakness, and hypokalemia. Subsequent investigations, including 24-h urinary free cortisol, 48-h low-dose dexamethasone suppression test, MRI of the sella, and bilateral inferior petrosal sinus sampling, confirmed CD without any evidence of ectopic ACTH production. She became eucortisolemic with medical therapy of ketoconazole and cabergoline, subsequently regained her weight, and became normokalemic. This case illustrates that patients with CD may present with symptoms and biochemical findings that would otherwise suggest ectopic ACTH production.

Learning points

• Patients with CD do not always present with classical clinical features and may present with symptoms and biochemical findings that would otherwise suggest ectopic ACTH production.

• While most patients with CD typically lose weight after biochemical remission, some patients gain weight after the normalization of cortisol levels.

• This case highlights the need to entertain a broad differential in patients presenting with hypokalemia and weight loss and the need to exclude hypercortisolemia.

Summary

Ovarian hyperstimulation syndrome (OHSS) usually occurs in patients undergoing assisted reproduction techniques and ovulation induction. Its variant, spontaneous ovarian hyperstimulation syndrome, a potentially life-threatening disorder, is uncommon and only a few cases have been reported in association with hypothyroidism. This study analysed five patients with untreated chronic hypothyroidism presenting with multicystic ovaries, isosexual precocious puberty, and delayed bone age; subsequently, the follow-up and regression of ovarian pathology was assessed. Two patients had presented to the emergency department with menorrhagia and hypotension, of these, one had ovarian torsion at presentation. Three patients presented to the outpatient department: one for evaluation of short stature, one for premature menarche, and another with polycystic ovaries. They were all diagnosed with long-standing, untreated chronic hypothyroidism. There was regression of the size of the cystic ovaries on subsequent follow-up. In all these patients, long-standing hypothyroidism had resulted in ovarian hyperstimulation syndrome. The potentially life-threatening complications of this syndrome may be prevented by careful screening and a strong index of clinical suspicion at the outset.

Learning points

• Long-standing, untreated primary hypothyroidism may result in spontaneous ovarian hyperstimulation syndrome.

• A high index of suspicion is required for an early and accurate diagnosis.

• The requirement for interdepartmental collaboration between gynaecology and endocrinology departments is essential for the successful management of this life-threatening but easily treatable disorder.

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

Multiple endocrine neoplasia type 1 (MEN1) requires a high level of suspicion, and late diagnosis can lead to dire outcomes. Genetic counselling is an important part of management, with a lack of evidence surrounding an optimal approach in Aboriginal Australian populations. Our case surrounds a remote-dwelling 48-year-old Aboriginal Australian female who was reviewed by an inpatient endocrine team in 2020 for persistent hypercalcaemia on a background of a parathyroidectomy in 2011 for primary hyperparathyroidism (PHPT), while she was admitted to a local hospital for acute chronic abdominal pain. Relevant medical history included multiple pulmonary embolisms/deep vein thrombosis, myocardial infarction, atrial fibrillation, chronic thromboembolic pulmonary hypertension, right heart failure, human T-lymphotropic virus 1, recurrent abdominal pain, and gastro-oesophageal reflux disorder. Gastroscopies from 2013 and 2015 demonstrated chronic gastritis with hundreds of gastric polyps. Subsequent laboratory studies, neuroendocrine tumour (NET) screening, and CT imaging demonstrated a recurrence of PHPT and a new diagnosis of Zollinger–Ellison syndrome. A 68-gallium-DOTATATE PET/CT was in keeping with metastatic NET. Pituitary studies were normal. Genetic testing confirmed a rare heterozygous variant of c.207dupC in exon 2 of the MEN1 gene. Treatment was symptom based due to terminal comorbidities. Genetic counselling was attempted; however, cultural and logistical barriers were identified and the family declined further testing. Unfortunately, she died in 2021 from multifactorial respiratory failure. This case highlights the need for better approaches to genetic counselling systems for remote Aboriginal Australians and emphasizes the importance of early recognition and the challenges faced in remote areas in making such rare diagnoses.

Learning points

• Remote healthcare systems often lack access to adequate specialist care, resulting in delayed diagnosis of rare conditions and leading to morbidity and mortality.

• Further research and work need to be done to provide culturally appropriate genetic counselling systems in remote Aboriginal Australians.

• A high index of suspicion is required to diagnose MEN1.

• Consider MEN1 in any patient diagnosed with primary hyperparathyroidism, with age <40, and/or with the presence of multiglandular disease or with the presence of Zollinger–Ellison syndrome.

• MEN1 may be under-recognized in Aboriginal Australians.

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

Congenital adrenal hyperplasia (CAH) is one of the most common inherited rare endocrine disorders. This case report presents two female siblings with delayed diagnosis of non-classical CAH 3β-hydroxysteroid dehydrogenase type 2 (3βHSD2D/HSD3B2) despite early hospital admission and apparent CAH manifestations such as infections, hirsutism, menstrual disturbances, and PCOS phenotype. Initially, sister 1 was misdiagnosed with PCOS and then 11-hydroxylase deficiency (CYP11B1), based on ultrasound, biochemical findings, and negative genetic testing for 21-hydroxylase deficiency (CYP21A2). Additional diagnostic workup was performed when sister 2also presented with symptoms of androgen excess. Genetic testing for CAH/steroid disorders finally revealed that both siblings were compound heterozygous for two variants in the HSD3B2 gene: a frameshift variant, c.558dup, p.(Thr187Hisfs*17) and a novel missense variant, c.65T>C, p.(Leu22Ser). A Synacthen test showed an insufficient cortisol increase. In vitro studies of the variants in a cell model revealed loss of function for the p.(Thr187Hisfs*17) and partial activity for p.(Leu22Ser) confirming non-classic CAH. Overlapping symptomatology and lack of specialized knowledge on steroid biosynthesis and associated rarest forms of CAH may explain the delayed diagnosis. However, with newer diagnostic methods comprising a less biased approach, very rare forms of non-classical CAH may no longer be overlooked in the future.

Learning points

• Non-classic 3βHSD2 is likely underdiagnosed.

• Late diagnosis of mild non-classic 3βHSD2 does occur and one should be aware of this diagnosis.

• Early diagnosis of NCCAH may prevent many consequences such as severe hirsutism, prolonged menstrual irregularities, infertility, or even adrenal crisis with severe infections.

• Comprehensive steroid profiling and genetic testing should be used earlier, especially when in doubt about a diagnosis.

Summary

Riedel’s thyroiditis is the rarest form of thyroiditis, occasionally resulting in rapid thyroid enlargement and potential tracheal obstruction. Here, we detail the case of an 81-year-old woman with a medical history including Hodgkin lymphoma, Hashimoto’s thyroiditis, and multinodular goiter. She presented to the emergency room with stridor, cervical swelling, and breathing difficulties for over 2 days. CT scans revealed substantial thyroid enlargement causing significant glottal and tracheal compression, to a minimum tracheal diameter of 7 mm. Due to the severity of the compressive symptoms, orotracheal intubation and mechanical ventilation were deemed necessary. Surprisingly, despite the initial suspicion of malignancy given the rapid growth in the elderly, subsequent cytological and histological evaluations indicated a benign form of invasive fibrous thyroiditis – Riedel’s thyroiditis. Although surgical intervention was advised, the patient declined and opted for endobronchial treatment with a prosthetic stent and subsequent treatment with systemic glucocorticoids. Following successful treatment, she was discharged within a week and resumed normal activities without respiratory distress. This case is noteworthy for its rapid benign mass growth, rare emergent presentation, and the patient’s advanced age.

Learning points

• The rapid enlargement of the thyroid gland in elderly patients poses a diagnostic challenge, stemming from the higher occurrence of aggressive thyroid carcinomas.

• Despite the clinical presentation, a comprehensive diagnostic workup, including fine-needle aspiration and core-needle biopsy, is crucial for accurately distinguishing between benign and malignant causes of thyroid nodule enlargement.

• This case report illustrates diverse treatment options for Riedel’s thyroiditis, and the importance of individualized treatment plans based on the degree of airway obstruction, patient preferences, and response to initial interventions.

• Clinicians should contemplate the inclusion of glucocorticoids in the therapeutic regimen for Riedel’s thyroiditis, particularly in cases where surgical intervention is not feasible or declined by the patient.

Summary

Multiple endocrine neoplasia type 2 (MEN2) is a hereditary cancer syndrome caused by germline-activating pathogenic variants in the RET proto-oncogene. MEN2A is the most common subtype, with a risk for medullary thyroid cancer (MTC), pheochromocytoma (PHEO), and primary hyperparathyroidism (PHPT), whereas MEN2B is less common and associated with MTC and PHEO along with mucosal neuromas. Little is known about the specific RET germline heterozygous variant K666N. This variant has been described in very few families, and in most cases, patients were diagnosed with a very indolent MTC as the only feature. There is one case of MTC and bilateral PHEO. The RET K666N variant is not stratified yet by the American Thyroid Association, and data are limited on pathogenicity; therefore, appropriate screening and treatment of asymptomatic RET K666N carriers are unclear. Here, we report a family with a heterozygous germline RET K666N variant. The proband was identified when she experienced cardiogenic shock and multi-organ failure after an elective hysterectomy and subsequently was found to have PHEO, with genetic testing revealing the RET K666N germline variant. Patient consent was obtained through IRB protocol COMIRB #15-0516.

Learning Points

• The specific RET germline heterozygous variant K666N is rare and described in very few families, and in most cases, patients were diagnosed with a very indolent MTC as the only feature. Our proband is much younger and has PHEO, MTC, and PHPT.

• The RET K666N germline variant appears to be a low penetrance variant for MEN2.