Breast cancer in multiple endocrine neoplasia type 1 (MEN1).

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 .

Refractory spontaneous hypoglycaemia: a diagnostic conundrum

A frail 79-year-old lady with dementia presented with a 2-year history of frequent falls. Recurrent hypoglycaemic episodes were diagnosed and treated with continuous glucose infusion in multiple hospital admissions. Hypoadrenalism and hypothyroidism were ruled out. Whilst hypoglycaemic (blood glucose 1.6 mmol/L), both plasma C-peptide and proinsulin concentrations, were inappropriately elevated at 4210 pmol/L (174­960) and >200 pmol/L (0­7) respectively with plasma insulin suppressed at 12 pmol/L (0­180). Whilst reported cases of proinsulinoma are typically pancreatic in origin, radiological investigations of the pancreas in this patient did not identify abnormalities. Unexpectedly contrast CT identified a heterogeneously enhancing mass (6.6 cm) at the lower pole of the left kidney consistent with renal cell carcinoma. Non-islet cell tumour-induced hypoglycaemia has been associated with renal malignancy; however, a serum IGF2:IGF1 ratio measured at <10 effectively excludes this diagnosis. Concomitantly on the CT, extensive peripherally enhancing heterogeneous mass lesions in the liver were identified, the largest measuring 12 cm. A palliative approach was taken due to multiple comorbidities. On post-mortem, the kidney lesion was confirmed as clear cell renal carcinoma, whilst the liver lesions were identified as proinsulin-secreting neuroendocrine tumours. In conclusion, the diagnosis of proinsulinoma can be missed if plasma proinsulin concentration is not measured at the time of hypoglycaemia. In this case, the plasma insulin:C-peptide ratio was too high to be accounted for by the faster relative clearance of insulin and was due to proinsulin cross-reactivity in the C-peptide assay. In addition, the concomitant malignancy proved to be a challenging red herring. Learning points: •• Even in non-diabetics, hypoglycaemia needs to be excluded in a setting of frequent falls. Insulin- or proinsulinsecreting tumours are potentially curable causes. •• Whilst investigating spontaneous hypoglycaemia, if plasma insulin concentration is appropriate for the hypoglycaemia, it is prudent to check proinsulin concentrations during the hypoglycaemic episode. •• Proinsulin cross-reacts variably with C-peptide and insulin assays; the effect is method dependent. In this case, the discrepancy between the insulin and C-peptide concentrations was too great to be accounted for by the faster relative clearance of insulin, raising the suspicion of assay interference. The C-peptide assay in question (Diasorin liaison) has been shown to be 100% cross reactive with proinsulin based on spiking studies with a proinsulin reference preparation. •• Whilst reported cases of proinsulinoma and 99% of insulinomas are of pancreatic origin, conventional imaging studies (CT, MRI or ultrasound) fail to detect neuroendocrine tumours <1 cm in 50% of cases. •• The concomitant renal mass identified radiologically proved to be a red herring. •• In view of the rarity of proinsulinoma, no conclusive association with renal cell carcinoma can be established.

Marked hyperandrogenicity in a 60-year-old woman.

Markedly elevated androgen levels can lead to clinical virilization in females. Clinical features of virilization in a female patient, in association with biochemical hyperandrogenism, should prompt a search for an androgen-producing tumor, especially of ovarian or adrenal origin. We herein report the case of a 60-year-old woman of Pakistani origin who presented with the incidental finding of male pattern baldness and hirsutism. Her serum testosterone level was markedly elevated at 21 nmol/L (normal range: 0.4-1.7 nmol/L), while her DHEAS level was normal, indicating a likely ovarian source of her elevated testosterone. Subsequently, a CT abdomen-pelvis was performed, which revealed a bulky right ovary, confirmed on MRI of the pelvis as an enlarged right ovary, measuring 2.9 × 2.2 cm transaxially. A laparoscopic bilateral salpingo-oophorectomy was performed, and histopathological examination and immunohistochemistry confirmed the diagnosis of a Leydig cell tumor, a rare tumor accounting for 0.1% of ovarian tumors. Surgical resection led to normalization of testosterone levels. LEARNING POINTS: Hirsutism in postmenopausal women should trigger suspicion of androgen-secreting tumorExtremely elevated testosterone level plus normal DHEAS level point toward ovarian sourceLeydig cell tumor is extremely rare cause of hyperandrogenicity.