A pitfall in diagnosing Cushing's disease: ectopic ACTH-producing pituitary adenoma in the sphenoid sinus.

PURPOSE: To show a rare case of Cushing's disease and possible cause of failed transsphenoidal surgery. METHOD: We report on a 50-year-old woman suffering from ACTH-dependent Cushing's syndrome. Endocrinological work-up including low-dose/high-dose dexamethasone test (Liddle-test) and CRH test were clearly compatible with pituitary origin. Although an MRI showed no pituitary tumor, CRH-stimulated petrosal sinus sampling revealed a significant central-peripheral gradient in ACTH concentrations, rendering Cushing's disease very likely. The patient underwent transsphenoidal surgery with negative exploration of the pituitary gland. After intraoperative re-evaluation of the preoperative MRI, a "polyp" at the bottom of the sphenoid sinus was identified. The intraoperative microscopic aspect as well as instantaneous sections and cytology of a biopsy confirmed an adenoma, which was then removed. Histological analysis demonstrated an ACTH-producing pituitary adenoma adjacent to respiratory mucous membrane consisting of ciliated epithelium with submucous connective tissue. Postoperatively, ACTH concentrations were decreased and intermittent hydrocortisone substitution treatment was initiated. At the 3-month follow up, Cushing's stigmata were found to be alleviated and the hydrocortisone dosage could be reduced. CONCLUSION: Ectopic pituitary adenoma tissue causing Cushing's disease is extremely rare but a potential cause for surgical failure or re-evaluation.

Double-phase Tc-99m MIBI scintigraphy in secondary hyperparathyroidism relapsing after parathyroidectomy and removal of a parathyroid autograft.

A 53-year-old woman with chronic renal failure had secondary hyperparathyroidism relapsing after undergoing a second parathyroidectomy and excision of an autologous parathyroid graft that had been implanted after her first parathyroidectomy. Double-phase scintigraphy with Tc-99m MIBI disclosed pathologic MIBI uptake in the right anterior thorax where the parathyroid transplant had been placed. Histopathologic examination of three nodules excised from this region yielded hyperplastic parathyroid tissue. This case report further illustrates the value of double-phase Tc-99m MIBI scintigraphy in atypical cases of hyperparathyroidism.

Hemofiltration in myoglobinuric acute renal failure.

The frequency of myoglobinuric renal failure is estimated between 8 and 20%. Despite early onset of therapy often the use of renal substitution by hemodialysis or hemofiltration is required. This study of the clinical course of nine patients with myoglobinuric acute renal failure reveals continuous arterio-venous hemofiltration (CAVH) to have an effective clearance for myoglobin. Thus, the time until recovery of renal function as well as the frequency of secondary complications in rhabdomyolysis induced acute renal failure can be distinctly reduced.

[Rare variants and unusual course of Cushing's syndrome]. / Seltene Varianten und Verlaufsformen des Cushing-Syndroms.

Cushing's syndrome is a rarely observed disease with a poor prognosis when not treated appropriately. Knowledge of clinical features of the different forms of the disease together with a specific and subtle method of cortisol detection is indispensable for an early out-patient diagnostic program. In this study the characteristic features of the rare benign and malignant forms of Cushing's syndrome are presented in typical case-reports. As it has been proven in clinical experience, the necessary diagnostic measures for clarification of the syndrome consists of only few methods reliable concerning their diagnostic validity. The success of any curative treatment of the benign forms or any palliative measure of the malignant forms essentially depends on early diagnosis and differentiation of the various appearances of Cushing's disease.

Differences in plasma and tissue aluminum concentrations due to different aluminum-containing drugs in patients with renal insufficiency and with normal renal function.

The gastrointestinal absorption of aluminum from orally administered aluminum-containing drugs is well documented. Retention of the absorbed aluminum leads to elevated levels of this metal in the tissue of patients with renal failure. We studied two groups of dialysis patients who had received equal amounts of the different aluminum-containing phosphate-binders Aludrox and Antiphosphat. It has recently been shown that Antiphosphat releases only a few aluminum ions in an environment of low pH. Consistent with this finding, we found the aluminum levels to be significantly higher in the plasma, bone, and hair of patients who had received Aludrox as phosphate binder. Subjects with normal renal function excreted most of the ingested and absorbed aluminum. No data are available concerning the tissue load of the element in these subjects. We studied two groups of patients with normal renal function who had received antacid drugs prior to neurosurgery on a brain tumor. The first group of patients were treated with an aluminum-rich antacid (Maalox 70); the other group received an aluminum-poor drug (magaldrate) for 10 days prior to the operation. Analysis of the brain-tissue removed revealed twofold higher aluminum levels in the patients who had received Maalox 70. These results indicate that administration of aluminum-containing drugs leads to a tissue load of aluminum in patients with an impaired renal function as well as in those with a normal function. The extent of the aluminum load depends on the aluminum content and the liberation rate of the drug.

Localization procedures in pheochromocytoma and neuroblastoma.

Localization procedures are required in catecholamine-producing tumors after clinical and biochemical confirmation. Computed tomography, ultrasound and/or 131I-metaiodobenzylguanidine (131I-MIBG) scintigraphy was performed in patients with pheochromocytoma, neuroblastoma and metastases of carcinoid tumors. Whereas computed tomography and ultrasound reflect morphological abnormalities, adrenomedullary scintigraphy depends on hormonal activity and other factors. 131I-MIBG scintigraphy has the advantage of detecting extraadrenal, multilocular and malignant pheochromocytomas. Especially small lesions and tumor tissue in bone marrow in children with neuroblastoma can be visualized more easily.

Primary aldosteronism: diagnosis and noninvasive lateralization procedures.

In 72 patients with primary aldosteronism who were classified on the basis of adrenal pathology after adrenalectomy, analysis of routine clinical and laboratory data, of supine and upright plasma aldosterone, and of plasma renin activity were of limited value in differentiating patients with aldosterone-producing adenoma(s) (APA, n = 59) from those with idiopathic adrenal hyperplasia (IAH, n = 13). Normokalemic aldosteronism occurred in 6 patients (3 APA, 3 IAH). A correct classification of the adrenal lesion(s) was obtained in 80% of the patients by computed tomography and only in 69% by adrenal scintiscan. In addition, adrenal scintiscan was hampered by a relatively high rate of incorrect results independent of whether dexamethasone was used or not. Small adenomas (less than 1 cm) and more often adrenal hyperplasia may escape visualization by computed tomography.