Summary

Moyamoya syndrome (MMS) refers to a rare cerebrovascular disorder characterized by progressive stenosis of the intracranial internal carotid arteries and their proximal branches, leading to an increased risk of stroke. While prevalent in Asia, this condition is considerably less common in Western countries, including Europe. The association between MMS and Graves’ disease (GD) has been well documented, primarily in Asian and American populations, notably Latin Americans. In this report, we report the first case of GD with MMS in a Caucasian woman from Western Europe. The precise mechanisms underpinning the correlation between these two conditions remain poorly elucidated but are hypothesized to involve hemodynamic alterations, the toxic effects of anti-thyroid-stimulating hormone receptor antibodies, or a shared genetic predisposition. Our clinical case underscores the significance of thyroid disease screening in suspected MMS cases, as the management of thyroid dysfunction may suffice to improve neurological symptoms.

Learning points

• The association between Graves’ disease (GD) and Moyamoya syndrome (MMS) can manifest in a Caucasian European patient.

• Screening for thyroid disease is essential when MMS is suspected, as treating GD might effectively alleviate neurological symptoms.

• The mechanisms linking GD and MMS remain incompletely understood but may involve hemodynamic shifts, the toxic effect of anti-TSH receptor antibodies, or shared genetic factors.

Summary

Hemichorea–hemiballismus (HCHB) syndrome is a syndrome characterized by choreic movements which are irregular, nonrepetitive, and random movements, and ballismus which are spontaneous and violent movements. HCHB syndrome with a metabolic cause is a rare presentation that can be precipitated by uncontrolled diabetes. Presented here is a case of HCHB syndrome with right-sided neuroimaging findings and contralateral chorea due to uncontrolled type 2 diabetes mellitus. This patient was found to be obtunded with a blood glucose of greater than 500 mg/dL by EMS. After the administration of insulin, she was able to answer clarifying questions of noncompliance with her antihyperglycemic medications. She had a computed tomography without contrast of the head which showed hyperdense lesions in the right caudate nucleus and putamen consistent with HCHB syndrome. She was started on treatment for nonketotic hyperglycemia with insulin. As her mentation improved, she was able to cooperate with physical examination, which revealed irregular and violent movements in the left upper and lower extremities. Her hemichorea and hemiballismus improved with strict glycemic control, and she was able to be discharged to a skilled nursing facility for further rehabilitation. She would later have repeated hospitalizations for poor glycemic control, and repeat neuroimaging would reveal the resolution of hyperdensities after 4 months. HCHB syndrome due to uncontrolled diabetes has been termed diabetic striatopathy and is characterized by poor glycemic control, unilateral striatal hyperdensity on CT imaging, and contralateral choreic movements. Diabetic striatopathy remains a poorly understood disease, and the exact pathophysiologic mechanism has not been definitively elucidated.

Learning points

• Diabetic striatopathy is a relatively new term for metabolic etiology of hemichorea–hemiballismus syndrome and was coined in 2009.

• The triad for diabetic striatopathy is poor glycemic control, unilateral striatal hyperdensity on CT imaging, and contralateral choreic movements.

• Multiple etiologies have been suggested for the cause of diabetic striatopathy including petechial hemorrhage, mineral deposition, myelin destruction, and infarction with reactive astrocytosis; however, the exact mechanism has yet to be determined.

• Antidopaminergic medications may be used to control the choreic movements of diabetic striatopathy; however, the mainstay of treatment is glycemic control, often with insulin therapy.

Summary

The resistance to thyroid hormone syndrome (RTHβ) occurs uncommonly and requires a high level of clinical suspicion and specific investigations to reach a precise diagnosis and to avoid unnecessary and potentially harmful therapies. We report a case of a young male patient referred to our unit for SARS-CoV-2 infection and atrial fibrillation with elevated thyroid hormones and non-suppressed thyroid-stimulating hormone (TSH), for which antithyroid therapy was prescribed. A mood disorder was reported in the medical history. The family history was unknown as the patient was adopted. Thyroid-specific antibodies were undetectable, and thyroid ultrasound revealed a normal thyroid gland without nodules. After the resolution of SARS-CoV-2 infection, the diagnostic workup continued, and the pituitary MRI revealed a small area ascribable to a microadenoma. Due to atrial fibrillation, the execution of the T3 test was contraindicated. The octreotide long-acting release (LAR) test showed an initial reduction of free thyroid hormones levels at first administration, which was consistent with the presence of a TSH-secreting pituitary tumour, although an escape from the response was observed after the following two injections of octreotide LAR. Indeed, the genetic investigation revealed a variant in heterozygosity of the THRβ gene (Pro453Ser), thus leading to an RTHβ diagnosis, and, therefore, medical treatment with triiodothyroacetic acid was initiated. After 2 years from the SARS-CoV-2 infection, the patient continues the follow-up at our outpatient clinic, and no other medical interventions are needed.

Learning points

• RTHβ is a rare genetic syndrome characterised by discrepant thyroid function tests and by a dissociation between the observed hormone levels and the expected patient signs and symptoms.

• Features of thyroid hormone deficiency in TR-ß dependent tissues (pituitary gland, hypothalamus, liver and neurosensitive epithelia), as well as thyroid hormone excess in TR-α-dependent tissues (heart, bone, skeletal muscle and brain), may coexist in the same individual.

• Clinical pictures can be different even when the same variant occurs, suggesting that other genetic and/or epigenetic factors may play a role in determining the patient’s phenotype.

• Differentiating RTHβ from a TSH-secreting pituitary tumour is very difficult, especially when a concomitant pituitary adenoma is detected during diagnostic workup. The injection of long-acting somatostatin analogues can help differentiate the two conditions, but it is important to detect any interference in the dosage of thyroid hormones to avoid an incorrect diagnosis.

• Genetic testing is fundamental to prevent unnecessary and potentially harmful therapies.

• Medical treatment with triiodothyroacetic acid was demonstrated to be effective in reducing thyroid hormone excess and controlling symptoms.

Summary

We report a case of a 59-year-old woman with Cushing’s disease who developed hyperthyroidism following treatment of hypercortisolaemia. The patient with a history of recurrent hospitalisations caused by multi-sited soft tissue abscesses was admitted with sepsis. Both her medical history and physical examination suggested Cushing’s syndrome. The initial hormonal diagnostic process, conducted after sepsis treatment, brought forth conflicting results. However, hormonal assessment repeated 3 months later indicated pituitary hypercortisolaemia, which was confirmed through bilateral inferior petrosal sinus sampling and was successfully treated with transsphenoidal pituitary surgery. Three months after the surgery, the patient was readmitted to our epartment with symptoms of hyperthyroidism, which was confirmed by laboratory tests. Thyroid scintiscans indicated Graves’ disease. However, the absence of anti-thyroid stimulating hormone antibodies suggested other etiologies of hyperthyroidism. Eventually, the patient underwent radioiodine therapy. Currently, her condition is improving and she has had no recurrence of abscesses, severe infections, or hyperthyroidism. In conclusion, while clinical manifestation of hypercortisolaemia might be non-specific, its treatment may trigger the development of autoimmune diseases.

Learning points

• The presence of recurrent severe infections should prompt physicians to consider the possibility of hypercortisolaemia.

• Chronic hypercortisolism is debilitating and can lead to significant disability.

• Dexamethasone suppression testing in patients with active or recent severe inflammatory or infectious illnesses may produce misleading or confusing results.

• Clinicians should be aware of the potential development of autoimmune diseases following successful treatment of hypercortisolaemia.

Summary

A previously healthy 17-year-old female presented to the emergency department with complaints of vomiting, shortness of breath, and tachycardia. She was found to have an elevated blood glucose and was admitted for presumed new onset type 1 diabetes mellitus (T1DM). During the admission, she was noted to have frequent episodes of hypoglycemia despite conservative insulin dosing and high urine output with glucosuria, which seemed out of proportion to her glucose levels and fluid status. She also had persistent hyponatremia despite normalization of blood glucose. Further work-up was initiated to investigate alternative or additional diagnoses to explain these atypical findings. Adrenocorticotropic hormone (ACTH) level was elevated, consistent with the diagnosis of Addison’s disease, which led to the subsequent diagnosis of autoimmune polyglandular syndrome type II (APS-2). This is one of the first reports in the literature of concurrent diagnosis of T1DM and Addison’s disease at initial presentation and demonstrates the importance of not anchoring to one diagnosis.

Learning points

• This case shows the importance of considering multiple diagnoses and investigating atypical signs and symptoms.

• This case highlights the importance of a thorough history including review of systems.

• Hyponatremia and recurrent hypoglycemia in a person with type 1 diabetes should raise suspicion for adrenal insufficiency.

• This case makes us consider the screening for Addison’s disease in a person with new onset type 1 diabetes in addition to autoimmune thyroid disease and celiac disease.

• People with an autoimmune disease should be monitored for other autoimmune diseases in the future.

Summary

RET mutations are implicated in 60% of medullary thyroid cancer (MTC) cases. The RET-selective tyrosine kinase inhibitor selpercatinib is associated with unprecedented efficacy compared to previous multi-kinase treatments. Langerhans cell histiocytosis (LCH) is a clonal histiocytic neoplasm usually driven by somatic BRAF mutations, resulting in dysregulated MAPK signalling. We describe a 22-year-old woman with metastatic MTC to regional lymph nodes, lung and liver. Tumour tissue harboured a somatic pathogenic RET variant p.(M918T) and selpercatinib was commenced. She experienced sustained clinical, biochemical and radiological responses. Two years later, she developed rapidly progressive apical lung nodules, prompting biopsy. Histopathology demonstrated LCH with a rare BRAF variant p.(V600_K601>D). The lung nodules improved with inhaled corticosteroids. We hypothesize that selective pressure from RET blockade may have activated a downstream somatic BRAF mutation, resulting in pulmonary LCH. We recommend continued vigilance for neoplasms driven by dysregulated downstream MAPK signalling in patients undergoing selective RET inhibition.

Learning points

• Patients with RET-altered MTC can experience rapid disease improvement and sustained disease stability with selective RET blockade (selpercatinib).

• LCH is a clonal neoplasm driven by MAPK activation, for which the most common mechanism is BRAF mutation.

• Both MTC and pulmonary LCH are driven by dysregulated MAPK signalling pathway activation.

• We hypothesise that the RET-specific inhibitor selpercatinib may have caused the activation of dormant LCH secondary to selective pressure and clonal proliferation.

Summary

Total testosterone, which is peripherally converted to its biologically active form dihydrotestosterone (DHT), is the first-line hormone investigation in hyperandrogenic states and infertility in premenopausal women. Polycystic ovary syndrome (PCOS), the most common cause of hyperandrogenism and infertility in young women, is often associated with mild elevations of total testosterone. Whereas very high levels of total testosterone (>2–3 SD of normal reference), are most often associated with hyperandrogenic signs, menstrual irregularity, rapid onset of virilization, and demand a prompt investigation. Herein, we report a case of a 32-year-old woman who was referred to the endocrinology outpatient clinic due to secondary amenorrhea and extremely high testosterone levels without any virilization signs. We initially suspected pitfalls in the testosterone laboratory test. Total serum testosterone decreased after a diethyl-ether extraction procedure was done prior to the immunoassay, but testosterone levels were still elevated. An ovarian steroid-cell tumor (SCT) was then revealed, which was thereby resected. Twenty-four hours post surgery, the total testosterone level returned to normal, and a month later menstruation resumed. This case emphasizes that any discrepancy between laboratory tests and the clinical scenario deserves a rigorous evaluation to minimize misinterpretation and errors in diagnosis and therapeutic approach. Additionally, we describe a possible mechanism of disease: a selective peripheral target-tissue response to high testosterone levels that did not cause virilization but did suppress ovulation and menstruation.

Learning points

• Total testosterone is the most clinically relevant hormone in investigating hyperandrogenic states and infertility in premenopausal women.

• Very high total testosterone levels in women (>2–3 SD of normal reference) are most often associated with hyperandrogenic signs, menstrual irregularities, and a rapid onset of virilization.

• In women with very elevated testosterone levels and the absence of clinical manifestations, laboratory interference should be suspected, and diethyl ether extraction is a useful technique when other methods fail to detect it.

• Ovarian steroid cell tumors (SCT) encompass a rare subgroup of sex cord-stromal tumors and usually secrete androgen hormones. SCTs are clinically malignant in 25–43% of cases.

• A selective response of peripheral target tissues to testosterone levels, with clinical manifestations in some tissues and no expression in others, may reflect differences in the conformation of tumor-produced testosterone molecules.

Summary

Struma ovarii is an ovarian teratoma that comprises 2–5% of all ovarian teratomas. Malignant transformation of struma ovarii occurs in less than 5% of all cases, and metastatic disease is even rarer. We report two cases initially diagnosed with benign struma ovarii that presented malignant transformation, specifically highly differentiated follicular carcinoma of the ovary (HDFCO), some years after the first diagnosis. Case 1 concerns a 37-year-old female featuring HDFCO of the right ovary with multiple metastatic foci, who was diagnosed with benign struma ovarii 14 years ago. Case 2 concerns a 26-year-old female diagnosed with HDFCO of the left ovary. This patient was initially diagnosed with benign struma ovarii 6 years ago that recurred 4 years after the diagnosis. Both patients were treated with surgery, adjunctive total thyroidectomy, and radioactive iodine (¹³¹I) therapy.

Learning points

• Malignant transformation of struma ovarii is very rare (<5%).

• Diagnosis of HDFCO without extra ovarian dissemination is difficult due to the resemblance of its histological appearance with normal thyroid tissue.

• There is no consensus on the postoperative treatment of malignant struma ovarii (MSO). Clinical and histological features of MSO should be assessed for the postoperative treatment decisions.

• TSH suppression and thyroglobulin level measurements are necessary for patient follow-up.

Summary

Approximately 80% of adrenal incidentalomas are benign, and development into adrenal cortical cancer is extremely rare. This is a major reason behind clinical guidelines recommending surveillance of incidentalomas for a relatively short duration of up to 5 years. Surveillance of lesions less than 1 cm is not routinely recommended. A 70-year-old lady was diagnosed with a non-hyperfunctioning 8 mm right adrenal lesion. She underwent annual biochemical and radiological assessment for 5 years before surveillance was extended to 2-yearly intervals. The lesion was stable in size, and radiological characteristics were consistent with a benign adenoma. Seven years after the initial detection of the adrenal lesion, she developed acute abdominal pain. Imaging revealed a 7 cm right adrenal lesion, which was surgically resected and histologically confirmed to be adrenal cortical cancer. She died 1 year later. Clinical guidelines have moved towards a shortened duration of surveillance of incidentalomas. Even though malignant transformation is a rare event, it is possible that this will result in a delayed diagnosis of adrenal cortical cancer, a highly aggressive malignancy with a poor prognosis. To our knowledge, this is the first published case of an adrenal lesion of less than 1 cm developing into adrenal cortical cancer.

Learning points

• Adrenal incidentalomas are increasingly common.

• Clinical practice guidelines exist to aid in differentiating benign and malignant lesions and assessing functional status.

• Transformation of adrenal incidentalomas to adrenal cortical carcinomas is a rare but recognised event.

Summary

Thyroid cancer is one of the most common manifestations of Cowden syndrome, yet the syndrome is rare. The incidence of Cowden syndrome is 1 in 200,000. The diagnosis can be made clinically when patients present with a combination of symptoms such as mucocutaneous lesions with a strong personal or family history of thyroid, breast, endometrial, and colorectal cancer. A high index of suspicion is required to provide a clinical diagnosis utilizing major and minor criteria. Once a clinical diagnosis is made, genetic testing for a PTEN mutation, a tumor suppressor gene, is recommended. Cancer surveillance should be performed for those with positive genetic testing as well as those with negative genetic testing who still meet clinical diagnostic criteria. We present two cases of Cowden syndrome: one case involving an increasing number of thyroid nodules in a patient with known Cowden syndrome and another patient with a strong family history of cancer, personal history of follicular thyroid cancer, and numerous colonic polyps on screening colonoscopy. These cases demonstrate how early diagnosis of Cowden syndrome can help detect early cancer in both the patient and affected relatives.

Learning points

• Diagnosing Cowden syndrome helps pre-risk stratification for early cancer screening.

• The diagnosis of Cowden syndrome can be made with a combination of major and minor criteria: any two major criteria with or without a minor criterion; one major and one minor criterion; or three minor criteria.

• Patients who meet the diagnostic criteria for Cowden syndrome should undergo genetic screening.