Summary

Middle ear adenomas with neuroendocrine features (ANEF) are rare, with an estimated 150 reported cases. They usually pursue an indolent clinical course. Four reported cases of middle ear ANEF with distant metastases were treated with surgery, external beam radiation therapy (EBRT) and chemotherapy. To date, no successful systemic treatment for malignant behaviour of this rare tumour has been reported. Long-acting somatostatin analogues (SSAs) and peptide receptor radionuclide therapy (PRRT) have been used in well-differentiated metastatic neuroendocrine tumours (NETs), but their use has never been described in cases of metastatic middle ear ANEF. We report two patients with grade 1 middle ear ANEF treated with surgery and EBRT. They had stable disease for several years, until clinical symptoms appeared and extensive metastases were detected on ⁶⁸Ga-DOTA⁰-Tyr³-octreotate (DOTATATE) PET/CT. Treatment with long-acting SSA was started, with stable disease for 1 year. Afterwards, despite undergoing local treatments, both patients presented progressive disease. Due to high-uptake metastases at ⁶⁸Ga-DOTATATE PET/CT, both cases underwent four cycles of PRRT with ¹⁷⁷Lu-DOTATATE, which secured disease control and improvement of quality of life in both. Similar to other well-differentiated NETs, SSA and PRRT could constitute efficacious therapeutic options in metastatic middle ear ANEF. Its neuroendocrine differentiation, potential to metastasize and somatostatin receptor type 2 expression prompt consideration and management of this disease as a neuroendocrine neoplasm.

Learning points

• Our cases oppose the 2017 WHO classification of middle ear adenoma with neuroendocrine features as a benign disease.

• This entity warrants long-term follow-up, as local recurrence or persistence of disease is reported in up to 18% of surgically treated patients.

• PET/CT scan with ⁶⁸Ga-labelled somatostatin analogues (SSA) can be used for staging of metastatic middle ear adenoma with neuroendocrine features.

• Unlabelled SSA and peptide receptor radionuclide therapy (PRRT) with radiolabelled SSA can be the first systemic therapeutic options for patients with advanced middle ear adenoma with neuroendocrine features.

Summary

A 34-year-old woman presented 18 months post-partum with blurred vision, polyuria, amenorrhoea, headache and general malaise. Comprehensive clinical examination showed left superior temporal visual loss only. Initial investigations revealed panhypopituitarism and MRI demonstrated a sellar mass involving the infundibulum and hypothalamus. Lymphocytic hypophysitis was suspected and high dose glucocorticoids were commenced along with desmopressin and thyroxine. However, her vision rapidly deteriorated. At surgical biopsy, an irresectable grey amorphous mass involving the optic chiasm was identified. Histopathology was initially reported as granulomatous hypophysitis. Despite the ongoing treatment with glucocorticoids, her vision worsened to light detection only. Histopathological review revised the diagnosis to partially treated lymphoma. A PET scan demonstrated avid uptake in the pituitary gland in addition to splenic involvement, lymphadenopathy above and below the diaphragm, and a bone lesion. Excisional node biopsy of an impalpable infraclavicular lymph node confirmed nodular lymphocyte-predominant Hodgkin lymphoma. Hyper-CVAD chemotherapy was commenced, along with rituximab; fluid-balance management during chemotherapy (with its requisite large fluid volumes) was extremely complex given her diabetes insipidus. The patient is now in clinical remission. Panhypopituitarism persists; however, her vision has recovered sufficiently for reading large print and driving. To the best of our knowledge, this is the first reported case of Hodgkin lymphoma presenting initially as hypopituitarism.

Learning points

• Lymphoma involving the pituitary is exceedingly rare and, to the best of our knowledge, this is the first reported case of nodular lymphocyte-predominant Hodgkin lymphoma presenting as hypopituitarism.

• There are myriad causes of a sellar mass and this case highlights the importance of reconsidering the diagnosis when patients fail to respond as expected to appropriate therapeutic intervention.

• This case highlights the difficulties associated with managing panhypopituitary patients receiving chemotherapy, particularly when this involves large volumes of i.v. hydration fluid.

Summary

We report a rare case of posterior reversible encephalopathy syndrome (PRES), precipitated by ectopic Cushing’s syndrome, in a patient with a metastatic pancreatic neuroendocrine tumour. A 55-year-old female presented as a hypertensive emergency with seizures and severe biochemical disturbance, including alkalosis, hypokalaemia and hyperglycaemia. MRI showed vasogenic oedema in the parieto-occipital region, consistent with a diagnosis of PRES. She had a significantly raised serum cortisol (>6000 nmol/L) which did not suppress with dexamethasone. Plasma adrenocorticotropic hormone (ACTH) concentrations were neither suppressed nor raised but were consistently within the normal reference range. The unexpected finding of a normal ACTH may be explained by either tumour secretion of unmeasured ACTH-related peptides, immunoassay antibody interference or episodic ACTH secretion. PRES is usually reversible with prompt and appropriate treatment. Hypercortisolism associated PRES is rare and may be associated with a worse outcome.

Learning points

• PRES secondary to ectopic Cushing’s syndrome is very rare.

• PRES in this context may indicate a worse prognosis.

• In ectopic Cushing’s syndrome, if the serum ACTH level is normal, consider testing for ACTH-related peptides or interfering antibodies.

• Further research is required to establish the best treatment approach and to improve patients’ outcomes.

Summary

A 38-year-old female was identified as carrying a heterozygous pathogenic MEN1 variant (c.1304delG) through predictive genetic testing, following a diagnosis of familial hyperparathyroidism. Routine screening for parathyroid and pituitary disease was negative. However, cross-sectional imaging by CT revealed a 41 mm pancreatic tail mass. Biopsy via endoscopic ultrasound confirmed the lesion to be a well-differentiated (grade 1) pancreatic neuroendocrine tumour (pNET) with MIB1<1%. Biochemically, hyperinsulinaemic hypoglycaemia was confirmed following an overnight fast, which was subsequently managed by diet alone prior to definitive surgery. Pre-operative work-up with octreotide SPECT CT demonstrated avid tracer uptake in the pancreatic lesion and, unexpectedly, a focal area of uptake in the left breast. Further investigation, and subsequent mastectomy, confirmed ductal carcinoma in situ pT2 (23 mm) grade 1, N0 (ER positive; HER2 negative). Following mastectomy, our patient underwent a successful distal pancreatectomy to resect the pNET. Loss of heterozygosity (LOH) at the MEN1 locus was found in both the breast tumour and pNET, thereby in keeping with a 'two-hit' hypothesis of oncogenesis, a suggestive but non-definitive clue for causation. To obtain further support for a causative relationship between MEN1 and breast cancer, we undertook a detailed review of the published literature which overall supports the notion that breast cancer is a MEN1-related malignancy that presents at a younger age and histologically, is typically of ductal subtype. Currently, clinical guidance regarding breast cancer surveillance in MEN1 does not exist and further research is required to establish a clinical and cost-effective surveillance strategy).

Learning points

• We describe a case of pNET and breast cancer diagnosed at a young age of 38 years in a patient who is heterozygous for a pathogenic MEN1 variant. Loss of the wild-type allele was seen in both breast tissue and pNET specimen.

• Breast cancer may be an under-recognised MEN1-associated malignancy that presents at a younger age than in the general population with a relative risk of 2–3.

• Further research is required to determine the cost-effectiveness of breast cancer surveillance approach at a younger age in MEN1 patients relative to the general population .

Summary

Succinate dehydrogenase deficiency has been associated with several neoplasias, including renal cell carcinoma (RCC) and those associated with hereditary paraganglioma (PGL)/ pheochromocytoma (PHEO) syndromes, Carney dyad, and Carney triad. Carney triad is a rare multitumoral syndrome characterized by co-existing PGL, gastrointestinal stromal tumor (GIST), and pulmonary chondroma (CHO). We report a case of a 57-year-old male who presented with para-aortic and gastroesophogeal masses, and a right renal superior pole lesion, which were classified as multiple PGLs, a GIST, and a clear cell renal carcinoma, respectively, on pathology following surgical resection. Additionally, a CHO was diagnosed radiologically, although no biopsy was performed. A diagnosis of Carney triad was made. SDHB immunohistochemical staining was negative for the PGL and the GIST, indicating SDH-deficiency. Interestingly, the renal cell carcinoma (RCC) stained positive for both SDHB and SDHA. Subsequent genetic screening of SDH subunit genes revealed a germline inactivating heterozygous SDHA pathogenic variant (c.91 C>T, p.R31X). Loss of heterozygosity was not detected at the tumor level for the RCC, which likely indicated the SDHA variant would not be causative of the RCC, but could still predispose to the development of neoplasias. To the knowledge of the authors this is the first reported case of an SDHA pathogenic variant in a patient with Carney triad complicated by RCC.

Learning points

• The succinate dehydrogenase enzyme is encoded by four subunit genes (SDHA, SDHB, SDHC, and SDHD; collectively referred to as SDHx), which have been implicated in several neoplasias and are classified as tumor suppressor genes.

• Carney triad is a rare multiple-neoplasia syndrome presenting as an association of PGLs, GISTs, and CHOs.

• Carney triad is most commonly associated with hypermethylation of SDHC as demonstrated in tumor tissue, but approximately 10% of cases are due to pathogenic SDHx variants.

• Although SDHB pathogenic variants are most commonly reported in SDH-deficient renal cell carcinoma, SDHA disease-causing variants have been reported in rare cases.

Summary

We present a 60-year-old woman who underwent successful surgical resection (partial pancreatectomy) for a low grade non-functioning pancreatic neuroendocrine tumour (pNET), with no biochemical or radiological features of recurrence on follow-up visits for 5 years. Fourteen years after the initial surgery, she developed spontaneous severe hypoglycaemic episodes which required hospitalisation, with subsequent investigations confirming the diagnosis of a metastatic insulin-secreting pNET (insulinoma). Medical management of her severe spontaneous hypoglycaemic episodes remained challenging, despite optimum use of diazoxide and somatostatin analogue therapy. Based on a discussion at the regional neuroendocrine tumour multidisciplinary team meeting, she underwent an elective hepatic trans-arterial embolization which was unfortunately unsuccessful. She ended up requiring an emergency right hemihepatectomy and left retroperitoneal mass resection which finally stabilised her clinical condition.

Learning points:

• Ours is only the seventh case report of a previously benign pNET presenting as a functional insulin secreting metastatic tumour. However, it is the first case report, in which the metastatic functional pNET presented after such a long hiatus (14 years).

• There is currently no clear consensus regarding the length of follow-up of non-functional pNET which are deemed cured post-surgical resection, with most guidelines advocating a median follow up of 5 years (1). The delayed presentation in our case suggests additional considerations should be made regarding optimal post-operative surveillance duration based on the age of the patient, location of the tumour, lymph node spread and Ki-67 index.

• Hepatic artery embolization and/or partial hepatectomy remains a treatment option for pNET patients with significant hepatic metastasis.

Learning points:

• Metastatic PTC should be considered in the differential diagnosis of a recurrent solitary cystic cervical lymph node.

• A dedicated thyroid ultrasound is the preferred modality for identifying thyroid lesion over computed tomography.

• There is a risk of non-diagnostic cytology following FNA for cystic neck lesions, largely predicted by the cyst content of the nodule.

Learning points:

• Severe Cushing syndrome can be effectively treated with fluconazole to achieve a significant improvement of hypercortisolism prior to bilateral adrenalectomy.

• Intravenous fluconazole is an alternative treatment when ketoconazole is not tolerated and etomidate is not available.

• Fluconazole is well tolerated with mild side effects. Hepatotoxicity is usually mild and resolves after drug discontinuation.

Learning points:

• In rare cases, glucagonoma may present with cardiac failure as the dominant feature. Significant cardiac impairment may occur in the absence of other features of glucagonoma syndrome due to subclinical chronic hyperglucagonaemia.

• A diagnosis of glucagonoma should be considered in patients with non-ischaemic cardiomyopathy, particularly those with other features of glucagonoma syndrome.

• Cardiac impairment due to glucagonoma may not respond to somatostatin analogue therapy, even in the context of biochemical improvement.

• All patients with a new diagnosis of glucagonoma should be assessed clinically for evidence of cardiac failure and, if present, a baseline transthoracic echocardiogram should be performed. In the presence of cardiac impairment these patients should be managed by an experienced cardiologist.

Learning points:

• Diagnosis of Cushing’s syndrome during pregnancy is complicated by several physiological alterations in hypothalamic–pituitary–adrenal axis regulation occurring in normal pregnancy.

• Cushing’s syndrome (CS) exacerbation during pregnancy can be associated with aberrant expression of LHCG receptor on primary adrenocortical tumour or hyperplasia in some cases, but not in this patient.

• Placental-derived ACTH, which is not subject to glucocorticoid negative feedback, stimulated cortisol secretion from this adrenal adenoma causing transient CS exacerbation during pregnancy.

• Following delivery and tumour removal, suppression of HPA axis can require several months to recover and requires glucocorticoid replacement therapy.