A Clinicopathologic and Molecular Analysis of Fumarate Hydratase-deficient Pheochromocytoma and Paraganglioma.

Up to 40% of pheochromocytomas (PCCs) and paragangliomas (PGLs) are hereditary. Germline mutations/deletions in fumarate hydratase ( FH ) cause hereditary leiomyomatosis and renal cell carcinoma syndrome which manifests predominantly with FH-deficient uterine/cutaneous leiomyomas and renal cell carcinomas (RCCs)-tumors characterized by loss of immunohistochemical (IHC) expression of FH and/or positive staining for S-(2-succino)-cysteine. Occasional patients develop PCC/PGL. We investigated the incidence, morphologic, and clinical features of FH-deficient PCC/PGL. We identified 589 patients with PCC/PGLs that underwent IHC screening for FH and/or S-(2-succino)-cysteine. Eight (1.4%) PCC/PGLs were FH deficient (1.1% in an unselected population). The median age for FH-deficient cases was 55 (range: 30 to 77 y) with 50% arising in the adrenal. All 4 with biochemical data were noradrenergic. Two (25%) metastasized, 1 dying of disease after 174 months. Germline testing was performed on 7 patients, 6 of whom had FH missense mutations. None were known to have a significant family history before presentation or developed cutaneous leiomyomas, or FH-deficient RCC at extended follow-up. The patient wild-type for FH on germline testing was demonstrated to have somatic FH mutation and loss of heterozygosity corresponding to areas of subclonal FH deficiency in her tumor. One patient did not undergo germline testing, but FH mutation was demonstrated in his tumor. We conclude that FH-deficient PCC/PGL are underrecognized but can be identified by IHC. FH-deficient PCC/PGL are strongly associated with germline missense mutations but are infrequently associated with leiomyoma or RCC, suggesting there may be a genotype-phenotype correlation. FH-deficient PCC/PGL may have a higher metastatic risk.

An unusual case of Cushing's syndrome due to bihormonal ACTH-prolactin secreting pituitary macroadenoma with rapid response to cabergoline.

A 23-year-old man presenting with florid Cushing's syndrome was found to have high plasma ACTH and very high serum prolactin. Pituitary MRI showed a large invasive macroadenoma. Low-dose cabergoline promptly suppressed both ACTH and prolactin levels within 2 weeks, with unexpected clinical and biochemical hypocortisolism requiring hydrocortisone replacement. Secondary hypogonadism was reversed. Clinical and biochemical remission of his Cushing's syndrome together with significant shrinkage of his macroadenoma has been maintained for 1 year on cabergoline 0.5 mg twice weekly. Reduction in pituitary tumour volume and brisk fall in serum prolactin in response to low-dose cabergoline is regularly observed in patients with macroprolactinomas, but the concurrent fall in the plasma ACTH level and hypocortisolism was a pleasant surprise. We assume that he most likely has a single bihormonal adenoma that is enriched with dopamine-2 receptors.

Neurological manifestations of phaeochromocytomas and secretory paragangliomas: a reappraisal.

OBJECTIVE: To determine the frequency and range of neurological manifestations of phaeochromocytomas and secretory paragangliomas. METHODS: A retrospective review of case notes of patients admitted to Auckland Hospital from 1985 to 2011 with a discharge diagnosis of phaeochromocytoma or secretory paraganglioma. RESULTS: Ninety-three patients were admitted with a phaeochromocytoma or secretory paraganglioma. Sixty-eight patients (73%) had neurological symptoms, but only 15 patients (16%) received a neurological consultation. Neurological manifestations occurred in three main clinical contexts. First, paroxysmal symptoms occurred in 66 of 93 patients (71%). Neurological symptoms were common features of these attacks and included headache (47 patients), anxiety (24 patients), tremulousness (15 patients) and dizziness (12 patients). The headaches typically had an explosive onset. Delay in diagnosis was common. Second, 28 patients (30%) had an acute crisis, which was associated with neurological symptoms in 11 (39%) of the episodes: headache (10 patients); seizures (five patients); strokes (three patients); delirium (three patients) and subarachnoid haemorrhage (one patient). Third, five of six patients with a head and neck secretory paraganglioma had neurological symptoms related to infiltration of the middle ear or compression of cranial nerves. Reversible cerebral vasoconstriction syndrome (RCVS) was documented in three patients. CONCLUSIONS: Neurological manifestations of phaeochromocytomas and secretory paragangliomas were common, and these tumours can present with various neurological manifestations. The paroxysmal symptoms can be incorrectly attributed to other headache syndromes, panic attacks or cerebral vasculitis. RCVS may play a role in the pathogenesis of the neurological symptoms associated with acute crises and paroxysmal attacks.

Rapid development of anterotibial compartment syndrome and rhabdomyolysis in a patient with primary hypothyroidism and adrenal insufficiency.

BACKGROUND: Anterior compartment syndrome (ACS) and rhabdomyolysis are rare complications of hypothyroid myopathy. We report the case of a young man with rapid onset of ACS who presented with simultaneous primary hypothyroidism and adrenal insufficiency associated with acute renal failure, hyponatremia, and hyperkalemia. PATIENT FINDINGS: A 22-year-old man presenting with a one-month history of tiredness, hyperpigmentation, and cramps in his calves was found to have severe bilateral foot drop. Investigations revealed severe primary hypothyroidism and adrenal insufficiency, renal failure, and evidence of rhabdomyolysis with myoglobinuria. Abnormal biochemical findings included serum sodium of 110 mM, serum potassium of 6.9 mM, and serum creatine kinase (CK) of >25,000 IU/L. Magnetic resonance imaging (MRI) of his legs showed changes of myonecrosis confined to anterior tibial muscles typical of ACS. After treatment with intravenous fluids, potassium-lowering therapies, thyroxine, and hydrocortisone, his renal and metabolic function returned to normal, but irreversible bilateral foot drop persisted. SUMMARY: A young man with primary hypothyroidism, adrenal insufficiency, hyponatremia, and hyperkalemia presented with severe myopathy, such that muscle necrosis, apparently confined to the anterior tibial compartment on MRI, led to rhabdomyolysis, acute renal failure, and irreversible bilateral peroneal nerve damage. It is possible that other patients with primary hypothyroidism and marked elevations of CK without widespread myopathy or rhabdomyolysis may demonstrate evidence of differential muscle effects in the anterior compartment when assessed by MRI, but that this patient also had adrenal insufficiency raises the possibility that this was a contributing factor. CONCLUSIONS: Severe thyroid myopathy and rhabdomyolysis may be associated with anatomic susceptibility to ACS, particularly in the presence of concomitant adrenal insufficiency. MRI examination reveals a distinctive appearance of myonecrosis confined to the anterior compartment.

Mortality and morbidity in Cushing's syndrome in New Zealand.

OBJECTIVE: Untreated Cushing's syndrome (CS) is associated with significant morbidity and mortality. However, recent operative series suggest low morbidity and mortality for CS, whereas population-based surveys report elevated mortality rates. We investigated the mortality and morbidity of CS in New Zealand. DESIGN: A nationwide retrospective survey of patients with CS between 1960 and 2005 managed at the four main endocrinology services. PATIENTS: A total of 253 patients with CS were identified, excluding adrenal carcinoma and malignant ectopic CS. MEASUREMENTS; The primary outcome was the standardized mortality ratio (SMR), comparing the observed number of deaths with the expected number for the population matched for age, sex and duration of follow-up. Secondary outcomes were the change in prevalence of co-morbidities at presentation and at final follow-up. RESULTS: The approximate prevalence and incidence of CS was 79/million and 1·8/million/y. The mean age at presentation was 39 year, and median duration of follow-up was 6·4 year (range 0-46). Overall, 89% achieved biochemical cure at last follow-up, with >90% achieving biochemical cure for CS from adrenal adenoma and pituitary causes. Thirty-six patients died during follow-up compared with 8·8 expected deaths (SMR 4·1, 95%CI 2·9-5·6). While hypertension, sexual dysfunction, myopathy and mild psychiatric illness were significantly reduced after treatment, hypertension, diabetes mellitus, moderate or major psychiatric illness, and osteoporosis were common at final follow-up. CONCLUSION: CS is associated with both high mortality and a high prevalence of co-morbidities, even when biochemical cure rates are between 80% and 90%.

Hot flushes, hypertension and haemodialysis.

Hypertension is common in patients with end stage renal disease. However, in patients non-responsive to standard measures to control the blood pressure, non-renal causes should be considered. We present the case of a patient on haemodialysis with difficult to control blood pressure.

A case of low cortisol-binding globulin: use of plasma free cortisol in interpretation of hypothalamic-pituitary-adrenal axis tests.

We investigated a patient with suspected hypopituitarism who showed subnormal cortisol responses to stimulation tests with adrenocorticotrophic hormone (ACTH) and hypoglycaemia, but normal ACTH and 11-deoxycortisol responses in the metyrapone test. Cortisol-binding globulin (CBG) was measured by enzyme-linked immunosorbent assay (ELISA), and was used to calculate plasma free cortisol and free cortisol index. The patient had a low plasma CBG concentration. Reinterpreted in terms of free cortisol and free cortisol index, his responses to ACTH were normal. We conclude that despite subnormal total cortisol responses to ACTH and hypoglycaemia, the patient had a normal hypothalamic-pituitary-adrenal (HPA) axis. Measurement of CBG concentration and calculation of free cortisol or free cortisol index can help avoid false interpretations of dynamic tests of the HPA axis based on plasma total cortisol.

Novel succinate dehydrogenase subunit B (SDHB) mutations in familial phaeochromocytomas and paragangliomas, but an absence of somatic SDHB mutations in sporadic phaeochromocytomas.

Phaeochromocytomas arising in adrenal or extra-adrenal sites and paragangliomas of the head and neck, in particular of the carotid bodies, occur sporadically and also in a familial setting. In addition to mutations in RET and VHL in familial disease, germline mutations in SDHD and SDHB genes that encode subunits of mitochondrial complex II have also been associated with the development of familial phaeochromocytomas. To further investigate the role of SDHD and SDHB in the development of these tumours we determined the occurrence of germline SDHD and SDHB mutations in four patients with a family history of phaeochromocytoma with associated head and neck paraganglioma, one patient with a family history of phaeochromocytoma only and two patients with apparently sporadic extra-adrenal phaeochromocytoma, one of whom had early onset disease. Secondly, we investigated whether somatic SDHB mutations correlated with loss of heterozygosity at 1p36 in a subgroup of 11 sporadic and three MEN 2-associated RET-mutation-positive phaeochromocytomas. Novel SDHB mutations were identified in the probands from four families and two apparently sporadic cases (six of seven probands studied), including two missense mutations, a single nonsense and frameshift mutation, as well as two splice site mutations, one of which was shown to have partial penetrance resulting in 'leaky' splicing. Further, five intronic polymorphisms in SDHB were found. No SDHD mutations were identified. In addition, no somatic SDHB mutations were found in the remaining allele of the 11 sporadic adrenal phaeochromocytomas with allelic loss at 1p36 or the three MEN 2-associated RET-mutation-positive phaeochromocytomas. Therefore, we conclude that SDHB has a major role in the pathogenesis of familial phaeochromocytomas, but the possible role of SDHB in sporadic tumours showing allelic loss at 1p36 has yet to be ascertained.