Selective Venous Catheterization Research Articles

Occipital bone and tumor-induced osteomalacia: a rare tumor site for an uncommon paraneoplastic syndrome

IntroductionTumor-induced osteomalacia (TIO) is an uncommon paraneoplastic syndrome due to the overproduction of fibroblast growth factor 23 (FGF23). It is predominantly caused by mesenchymal tumors and cured upon their complete removal. Non-surgical treatment is an alternative option but limited to specific clinical conditions.MethodsWe report a challenging case of TIO caused by a tumor involving the occipital bone. We also performed a literature review of TIO caused by tumors localized at this site, focusing on clinical findings, treatment, and outcomes.ResultsThe patient, a 62-year-old male, presented with a long-lasting history of progressive weakness. Biochemical evaluation revealed severe hypophosphatemia due to low renal tubular reabsorption of phosphate with raised intact FGF23 values. A 68 Ga-DOTATATE PET/TC imaging showed a suspicious lesion located in the left occipital bone that MRI and selective venous catheterization confirmed to be the cause of TIO. Stereotactic gamma knife radiosurgery was carried out, but unfortunately, the patient died of acute respiratory failure.To date, only seven additional cases of TIO have been associated to tumors located in the occipital bone. Furthermore, the tumor involved the left side of the occipital bone in all these patients.ConclusionThe occipital region is a difficult area to access so a multidisciplinary approach for their treatment is required. If anatomical differences could be the basis for the predilection of the left side of the occipital bone, it remains to be clarified.

A case of postmenopausal ovarian hyperandrogenemia diagnosed only by selective catheterization of ovarian vein

Hyperandrogenemia in a postmenopausal woman is usually related to a tumor in either ovaries or adrenal glands. To differentiate between these two endocrine organs is a diagnostic challenge when the tumor size is too small to be detected with the aid of usual imaging modalities. 54 years-old postmenopausal woman with signs of virilization was referred to our institution with serum total testosteron levels of 294 ng/dl. Contrast-enhanced computed tomography (CT) revealed a lesion consistent with the tumor 1 cm in diameter in the adrenal gland and magnetic resonance imaging (MRI) could not confirm this finding. The location of androgen hypersecretion could only be determined after selective venous catheterization and hormonal sampling of both adrenal and ovarian veins. The right ovarian venous total testosterone level was found as > 1009.40 ng / dl. A right-sided ovarian Leydig cell tumor was diagnosed in the specimen of laparoscopic hysterectomy and bilateral salpingo-oopherectomy. This case report underlines the importance to carry on the search with the selective venous catheterisation and hormonal sampling from both the ovarian and the adrenal veins when there is difficulty to demonstrate the true source of androgen hypersecretion in a postmenopausal woman.

Value of selective venous catheterization in the diagnosis of hyperandrogenism

To discuss the clinical utility of ovarian vessel sampling in the context of the evaluation and treatment of ovarian hyperthecosis. Patient presentation in video format, ovarian vessel sampling demonstration, surgical technique explanation, surgical histology discussion and ovarian hyperthecosis review. Academic medical center. A 30-year-old nulligravid female presented with severe hyperandrogenic features, consistent with polycystic ovary syndrome. During the course of her diagnostic evaluation, she underwent selective ovarian and adrenal vein sampling. Assessment of ovarian vessel testosterone levels and review of final histologic findings. Selective ovarian and adrenal vein sampling revealed right ovarian testosterone levels that were 200 times the upper limit of normal. As occult malignancy was a concern, laparoscopy was performed, with nearly complete removal of the right ovarian stroma. Pathology revealed ovarian stromal hyperthecosis without evidence of malignancy. Selective venous sampling is a technically challenging procedure, which may help localize an occult malignancy in limited circumstances. In utilizing selective venous sampling, one must consider the limitations of thetest, potential for false positive results, and possibility of unnecessary surgical interventions.

Educational Exhibit Abstract No. 374 - Parathyroid venous sampling: a review of the technique and its utility in localizing parathyroid adenoma

Learning Objectives To discuss the technique of venous catheterization and sampling for localization of parathyroid adenoma. To determine the relevance of parathyroid venous sampling at our institution by performing a retrospective analysis of 29 patients over a 6 year period. Background Selective thyroid venous catheterization and detection of a venous PTH gradient allow for lateralization of parathyroid adenoma. Because of the rare instances that the inferior thyroid vein is not the major venous drainage route, our institution samples multiple other regional veins, to ensure that, if present, a PTH gradient is detected. Clinical Findings/Procedure Details Patients are referred by a single surgeon to a single interventional radiologist for parathyroid venous sampling. Venous samples for intact parathyroid hormone are obtained from multiple veins including: superior thyroid, internal jugular, innominate, inferior thyroid, thymic (if identified), left superior intercostal, SVC (above and below azygos vein), right hepatic, IVC, and bilateral iliac. Results from 29 patients, over a 6 year period, demonstrate that parathyroid venous sampling alone, or in conjunction with 4-D Neck CT, is effective for pre-surgical lateralization of parathyroid adenoma. Conclusion and/or Teaching Points Although an uncommon procedure, it is important to understand the technique and application of parathyroid venous sampling. The procedure is successful at localizing parathyroid adenomas pre-operatively, resulting in shorter operating room times and reduced patient morbidity.

Selective venous catheterization for the localization of phosphaturic mesenchymal tumors

Tumor-induced osteomalacia (TIO) is characterized by renal phosphate wasting, hypophosphatemia, and aberrant vitamin D3 metabolism and is caused by fibroblast growth factor 23 (FGF-23)–producing mesenchymal tumors, which are often difficult to locate. We investigated the utility of selective venous sampling in tumor localization. The primary endpoint was identification of the FGF-23 concentration ratio between the venous drainage of the tumor bed and the general circulation that was diagnostic of the location of an FGF-23-secreting tumor. Fourteen subjects underwent 15 sampling procedures after functional and anatomic imaging studies. Subjects fit into three imaging categories: no suspicious site, multiple sites, and single site (positive controls). FGF-23 levels were measured by ELISA. Suspicious tumors were resected for diagnosis, confirmation, and cure. In subjects with a positive venous sampling study and subsequent cure, a minimum ratio of 1.6 was diagnostic. In 7 of 14 subjects there was suggestive imaging, a diagnostic ratio, and an associated TIO tumor (true positive). Four of these required complicated resection procedures. In 4 of 14 subjects with no suspicious site on imaging studies, an FGF-23 diagnostic ratio was not detected (true negative). Biopsy or resection of a single lesion in 2 of 14 subjects with a diagnostic ratio failed to identify a TIO tumor (false positive). A diagnostic FGF-23 ratio was absent in 1 of 14 subjects whose tumor was a single highly suspicious lesion on imaging studies (false negative). These data yield a sensitivity of 0.87 [95% confidence interval (CI) 0.47–0.99] and a specificity of 0.71 (95% CI 0.29–0.96). Selective venous sampling for FGF-23 was particularly useful in subjects with multiple suspicious sites or an anatomically challenging planned resection but not in the absence of a suspicious lesion on imaging studies. © 2011 American Society for Bone and Mineral Research.

What steps should be considered in the patient who has had a negative cervical exploration for primary hyperparathyroidism?

The key to cure of the patient with persistent primary hyperparathyroidism is a clear understanding of the investigations, operative procedure and pathology related to the initial procedure. Reinvestigation and subsequent surgery should be performed in a specialist unit. A logical pathway of increasingly sophisticated localization studies (MIBI, ultrasound, CT/MRI, selective venous catheterization for PTH) will usually guide the surgeon to the missing parathyroid gland/s. Improved preoperative localization can facilitate the use of a minimally invasive small incision approach. The surgeon must have a detailed knowledge of the nuances of parathyroid embryology and a meticulous surgical technique, not only to identify and safely remove the retained gland/s but also do so without causing unnecessary morbidity. Results of re-operation (84-98% cure) from centres of excellence are highly commendable, yet the use of 'new' technology (that includes intra-operative PTH) has not translated into improved outcomes in all cases. Some parathyroid glands are extremely difficult to find! Re-operative parathyroid surgery is a challenge, sometimes easy, and on other occasions extremely difficult.

Diagnostic strategies and surgical procedures in persistent or recurrent primary hyperparathyroidism.

The incidence of persistent or recurrent primary hyperparathyroidism reported in the literature lies between 1 and 10%. The main causes are represented by atypical locations or incorrect diagnosis of primary parathyroid hyperplasia. Since primary parathyroidectomy by an experienced surgeon has a success rate of 95%, there is no need for extended imaging studies prior to initial bilateral exploration. After confirming diagnosis of persistent or recurrent hyperparathyroidism exact localization studies are necessary. The most important procedures are ultrasonography, magnetic resonance imaging, technetium Tc99m sestamibi scintigraphy with a combined sensitivity of approximately 90%. In case of negative imaging results selective venous catheterization before reoperation can be performed. Reoperation by an experienced surgeon will be successful in 95% of cases.

Selective venous sampling for androgen‐producing ovarian pathology

Multiple diagnostic modalities may be needed to establish the source of excessive androgen production in women. The role of selective venous catheterization in this process has not been established fully. A study of hyperandrogenaemic subjects and literature review. Four hyperandrogenaemic women and an additional 132 previously reported cases with available testing data and a pathological diagnosis were evaluated. Serum androgens, diagnostic imaging and ovarian venous effluent sampling. Criteria to distinguish ovarian tumours from other ovarian conditions and to localize the lesion(s) were evaluated. Basal peripheral testosterone levels >or= 4.51 nmol/l (>or= 130 ng/dl) discriminated ovarian tumours from benign causes of hyperandrogenism (sensitivity: 93.8%, 95% CI 85.0-98.2; specificity: 77.8%, 95% CI 66.4-86.7). Single lesions produced higher ipsilateral testosterone concentrations (612.6 +/- 162.0 nmol/l; 17 653 +/- 4670 ng/dl) compared to contralateral values (26.4 +/- 5.2 nmol/l; 761 +/- 150 ng/dl). In women with peripheral testosterone >or= 4.51 nmol/l, a right-to-left (R:L) ovarian testosterone ratio >or= 1.44 correctly identified all 18 women with right-sided tumours and misclassified two with bilateral lesions; 12 out of 14 women with left-sided or bilateral lesions had a lower R:L value. When this criterion was combined with a left-to-right (L:R) ovarian testosterone effluent ratio of > 15 to identify left-sided tumours, overall 66% of women were correctly categorized. Peripheral testosterone concentrations identified ovarian androgen-producing tumours, and venous sampling could correctly localize 66% of these, suggesting a role for sampling when imaging studies are not revealing.

Reninoma: case report and literature review

Reninoma is a tumor of the renal juxtaglomerular cell apparatus that causes hypertension and hypokalemia via hypersecretion of renin. We describe a case of reninoma and provide a review of the literature, with a discussion emphasizing the diagnostic evaluation for such patients. The subject had persistent elevation of both plasma renin activity (PRA) and aldosterone. Imaging studies revealed the presence of a lesion in the renal cortex, which was further identified as a renin-producing lesion via selective venous catheterization following administration of an angiotensin-converting enzyme inhibitor (ACE-I). Following partial nephrectomy, the PRA and plasma aldosterone levels declined rapidly and the blood pressure and potassium supplementation requirements normalized. This case demonstrates the utility of both appropriate imaging studies and selective venous catheterization following provocative administration of an ACE-I for diagnosis.

How to localize parathyroid tumors in primary hyperparathyroidism?

The management of primary hyperparathyroidism (PHPT) has dramatically changed in the last 5 yr. Many more patients now undergo focused, limited or minimally invasive parathyroidectomy instead of traditional bilateral neck exploration. This change has taken place because of the improved accuracy of pre-operative localizing studies in selecting patients who have single-gland parathyroid disease (single adenoma) and can therefore have a minimally invasive parathyroidectomy. Sestamibi scanning followed by ultrasound, magnetic resonance imaging (MRI) and computed tomography (CT) scans are most accurate for localizing parathyroid tumors in patients with PHPT. Selective venous catheterization for PTH levels is useful when other localizing studies are negative or discordant in patients with persistent or recurrent PHPT. The routine use of one or more localizing studies commonly identifies the parathyroid tumor in patients with single-gland disease; but if localizing studies are negative or discordant, patients should have intra-operative PTH levels monitored or have a bilateral neck exploration to ensure a high rate of biochemical cure.

Localization and reoperation results for persistent and recurrent parathyroid carcinoma.

Reoperation is safe and benefits patients with persistent and recurrent parathyroid carcinoma. Retrospective study. The mean follow-up time was 8.1 years (median, 7 years; range, 1-23 years). A university tertiary referral center. Eighteen patients treated for parathyroid carcinoma from 1966 to 1999. The mean serum calcium level was 13.7 mg/dL (3.43 mmol/L), and the parathyroid hormone (PTH) level was 1.6 to 20 times the upper limit of normal. Fourteen of 18 patients had persistent or recurrent parathyroid carcinoma and underwent 54 reoperations (28 at our institution). Mean time to recurrence was 4.8 years (range, 1-20 years). Symptoms of hyperparathyroidism were relieved in 86% of patients who had reoperation (P<.05). Reoperation for parathyroid carcinoma (25 locoregional and 3 distant) significantly reduced and normalized the serum calcium and PTH levels in 75% and 62% of the cases, respectively (P<.001). The preoperative serum calcium level was a significant predictor of postreoperative normalization of the serum calcium level but not extent of initial resection, PTH level, time to recurrence, concordance of localization studies, or patient age and sex (P<.01). Surgical complications consisted of 5 unilateral and 1 bilateral permanent recurrent laryngeal nerve palsies (2 intentionally resected en bloc), 1 transient hypoparathyroidism, 1 wound seroma, and 1 tracheoesophageal fistula. The sensitivity rates of sestamibi scan (n = 14), magnetic resonance imaging (n = 15), computed tomographic scan (n = 6), ultrasound (n = 13), and selective venous catheterization with PTH measurement (n = 6) were 79%, 93%, 67%, 69%, and 83%, respectively. Recurrence is common in patients with parathyroid carcinoma. Patients with this disease should have frequent, lifelong follow-up to ensure early detection of recurrence. Although reoperation for persistent or recurrent parathyroid carcinoma provides significant symptomatic relief and normalizes serum calcium and PTH levels in most patients, it is associated with some morbidity. Localizing studies of parathyroid carcinoma are helpful but do not detect all tumor foci.

The Use of Imaging Studies in the Diagnosis and Management of Thyroid Cancer and Hyperparathyroidism

With the variety of radiopharmaceutical agents and refined imaging techniques, thyroid and parathyroid imaging provides much valuable clinical information. The use of imaging is most important in the follow-up of differentiated (DTC) and medullary thyroid cancer (MTC). Patients with DTC are followed with serum thyroidglobulin and 131I whole body scintigraphy when the serum thyroglobulin level is elevated. When the 131I scintigram is negative, 201Tl scintigraphy may best identify the site of recurrent DTC. Alternative radioisotopes, ultrasound, CT, and FDG PET are also useful in localizing the site of DTC metastases. MTC recurrences and metastases are more difficult to image. Selective venous catheterization is the most sensitive and specific method for detecting areas of recurrent MTC. High-resolution ultrasound, CT, MR imaging, and scintigraphy are all capable of, and useful in, detecting macroscopic foci of metastatic tumor. Somatostatin receptor scintigraphy and 99mTc DMSA have been the most frequently used nuclear imaging agents in patients with recurrent MTC. Imaging for hyperparathyroidism remains controversial. Sestambi has become the preferred isotope for parathyroid scintigraphy; whereas high-resolution ultrasound is also frequently used. Preoperative imaging is being used as a method to allow a unilateral neck exploration, more recently, in conjunction with intraoperative 1-84 PTH assay and with intraoperative use of the gamma probe. Most often, parathyroid imaging is performed before reoperation for persistent hyperparathyroidism.

Urokinase treatment of sagittal sinus thrombosis with venous hemorrhagic infarction

Selective catheterization of the dural venous sinuses with local infusion of urokinase may be beneficial in patients with venous sinus thrombosis, and has been reported to be safe in patients with venous infarction. However, information regarding safety in the presence of hemorrhage is sparse. Three patients presented with severe, progressive focal neurological symptoms (National Institutes of Health Stroke Scales: 14, 22, and 12) resulting from superior sagittal sinus thrombosis, with evidence of hemorrhage on computed tomographic scans (two intraparenchymal, one subarachnoid). Selective venous catheterization was performed and low-dose urokinase was delivered directly into the thrombus by continuous infusion at 60,000 U/h. Intravenous heparin was administered concurrently. Angiographic patency was restored in all patients. The total duration of urokinase infusion ranged from 36 to 84 hours. There was no major morbidity or mortality related to the procedure. All patients had dramatic clinical improvement during and after the course of therapy, and none had worsening of pre-existing hemorrhage. All patients were independent at 3 months, with minimal or no deficit (National Institutes of Health Stroke Scales: 2, 0, and 2). In selected patients with superior sagittal sinus thrombosis associated with venous hemorrhagic infarction, urokinase appears to be safe and may reverse progressive neurological deterioration. Future prospective study is warranted to further investigate this treatment option, and patients with severe deficits or pre-existing hemorrhages should not be excluded.

Partial or near-total pancreatectomy for persistent neonatal hyperinsulinaemic hypoglycaemia: the pathologist's role.

To determine whether the presence of abnormal B-cell nuclei predicts the existence of a focal or of a diffuse form of persistent neonatal and infantile hyperinsulinaemic hypoglycaemia in a series of 20 infants. Intra-operative frozen sections were performed on small specimens from the pancreatic head, isthmus and tail. In 13 cases, abnormal B-cell nuclei were identified, but even a near-total pancreatectomy was insufficient to cure some of these patients, in whom no focal lesion was detected. On the other hand, abnormal insular B-cell nuclei were not found in seven cases; based on the results of selective venous catheterization, a limited resection was performed, sufficient to cure each patient, and a focal adenomatous hyperplasia was found in each resected specimen. Intra-operative examination of small pancreatic specimens taken from the different parts of the gland allows one to determine the type of lesion (focal or diffuse) in neonatal onset hyperinsulinaemic hypoglycaemia, and to decide on the most appropriate surgical treatment.

Reoperation for persistent or recurrent primary hyperparathyroidism.

To analyse the causes and outcome of reoperations for persistent or recurrent primary hyperparathyroidism (HPT). We reviewed the medical records of 38 patients who underwent reoperation between December 1965 and April 1997 for persistent or recurrent primary HPT. During this period of time, 1448 patients underwent operation for primary HPT, 294 for renal HPT and 58 for questionable disease, i. e. a total of 1800. In the 1448 cases of HPT, 22 patients were reoperated after a first cervicotomy in the institution, i. e. a first reoperation rate of 1.5%. Sixteen patients were referred after unsuccessful parathyroid surgery. Six patients were reoperated on twice and one patient seven times for a graft-dependent recurrence. Reasons for failed parathyroid operations included tumour tissue in ectopic location (75%) or tumour tissue that had not been seen in normal position (19%), parathyreomatosis (2%), parathyroid cancer (2%) and graft-dependent hypercalcaemia (2%). Of the ectopic glands, 45 % were intrathymic, 12.5% intrathyroidal, 7.5% retro-oesophageal, 7.5% in the carotid sheath, 5% interthyrotracheal, 5% in the mediastinum (extrathymic), 5% in the aorto-pulmonary window, 2.5% undescended, 2.5% overdescended and 2.5% intertracheooesophageal. Of the patients, 38% had uniglandular lesions, 60% multiglandular lesions, and 2% parathyroid cancer. The histologically confirmed cause of HPT was adenoma in 50% of cases, hyperplasia in 38% and "normal" but overweight glands in 9.5%. Of the 38 patients studied, 15 presented one or more supernumerary glands (fifth to eighth gland). Reoperation was performed through a cervical incision in 82% of cases and using a mediastinal approach in 18% (8 median sternotomies, 1 thoracoscopy). The success rate of the reoperations was 92%. A total of 8% of patients suffered permanent unilateral vocal cord paralysis; 5% are definitely hypocalcaemic. The sensitivities of preoperative localization studies ranged from 69% for sestamibi scan and 63% for selective venous catheterization to 16% for computed tomography. Repeated parathyroidectomy can be avoided in more than 98% of patients if an experienced surgeon performs bilateral cervical exploration during the initial parathyroid operation. For patients with persistent or recurrent primary HPT, preoperative localization studies and a focused surgical approach can result in a 92% success rate with a minimal complication rate.

Outcome of surgical therapy in asymptomatic primary hyperparathyroidism

Surgery for symptomatic hyperparathyroidism remains the standard therapy. Asymptomatic primary hyperparathyroidism (pHPT) is being diagnosed with increasing frequency owing to broad serum testing. Indications for surgery in this setting are controversial. For evaluation of surgical safety we performed a retrospective analysis of our patients who were being operated on for asymptomatic pHPT. From January 1988 until August 1995, 243 patients were treated for pHPT and registered prospectively at our unit. Seventy-six patients were classified as asymptomatic. In all, 75% of the patients were female; the mean age was 62 years. In this group, 87% of the patients had cervical sonography in order to localize the adenoma. Highly selective venous catheterization was required in cervical reexplorations. Statistical analysis for potential prognostic factors for the clinical outcome was performed. Successful cervical exploration was possible in 71 patients (94.7%). With 4 patients remaining hypercalcemic, the rate of persistency was 5.2%. Localization procedures were correct in 58% for cervical ultrasound and 77% for selective venous catheterization. Postoperative morbidity included one permanent recurrent laryngeal nerve palsy and 2 patients with hemorrhage who were treated by reoperation. While one case of permanent hypoparathyroidism was well controlled by oral supplementation, 18 patients recovered from temporary hypoparathyroidism. No postoperative mortality occurred. Risk factor analysis revealed only cervical reexplorations for HPT to be associated with a higher morbidity (P = 0.02). Surgery for asymptomatic pHPT can be performed with reasonable safety. Cervical reexplorations in asymptomatic patients should be reserved for special indications. Apart from this small group, all patients should be evaluated for surgery.

Results of selective venous site-specific catheterization in occult C-cell carcinoma of the thyroid gland

Medullary thyroid carcinoma (MTC) can--even in recurrent cases--only be treated surgically. Therefore, preoperative localization of the tumor is essential. From April 1986 through April 1997, 137 patients with MTC were operated on at our clinic. In 22 patients with recurrent tumor which had not been radiologically localized, 28 selective venous catheterizations (SVC) with determination of calcitonin levels were carried out. In 23 examinations a suspected tumor could be identified (nine cervical unilateral, seven mediastinal, four cervical unilateral and mediastinal, one cervical bilateral and mediastinal, one liver, one cervical unilateral and liver). In 18 cases surgery was performed for recurrence (nine cervical revisions, one mediastinal dissection, six cervicomediastinal dissections, two laparotomies). In 15 of 18 cases, tumor tissue was found in the previously suspected area. In ten cases serum calcitonin levels dropped postoperatively by 6%-75%. A normalization of the hormone level was achieved only once by yet another operation. During further follow-up, five of the reoperated patients died from their disease. The other 17 patients are being followed up, whereby calcitonin levels are elevated but there is no clinical or radiological evidence of tumor. Although in the patient cohort presented a normalization of serum calcitonin could be achieved only once, the authors consider SVC useful because it is the only means of localization of tumor tissue in cases of negative radiologic studies and therefore allows a planned approach to the operation procedure in these cases.

Reoperation for Persistent or Recurrent Primary Hyperparathyroidism

To analyze the causes and outcomes of reoperation for persistent or recurrent primary hyperparathyroidism. Medical records of 102 patients with persistent or recurrent primary hyperparathyroidism who underwent reoperation by 1 surgeon between 1985 and 1995. Only patients with persistent or recurrent primary hyperparathyroidism were selected; patients with secondary hyperparathyroidism, parathyroid cancer, familial hyperparathyroidism, and previous thyroid operations were omitted. Performed by a single unblinded researcher. Reasons for failed parathyroid operations included tumor in ectopic position (53%), incomplete resection of multiple abnormal glands (37%), adenoma in normal position missed during previous surgery (7%), and regrowth of previously resected tumor (3%). Of the ectopic glands, 28% were paraesophageal, 26% in the mediastinum (nonthymic), 24% intrathymic, 11% intrathyroidal, 9% in the carotid sheath, and 2% in a high cervical position. Eighty-three percent of ectopic glands were accessible via cervical incision. The success rate of reoperations was 95%. One patient (1%) became permanently hypocalcemic after reoperation; 1 patient (1%) suffered permanent unilateral vocal cord paralysis. The sensitivities of preoperative localization studies were as follows: technetium Tc 99m sestamibi scan, 77%; magnetic resonance imaging, 77%; selective venous catheterization for intact parathyroid hormone, 77%; thallium-technetium scan, 68%; ultrasonography, 57%; and computed tomography, 42%. Repeated parathyroidectomy can be avoided in more than 95% of patients if an experienced surgeon performs bilateral cervical exploration during the initial parathyroid operation. For patients with persistent or recurrent primary hyperparathyroidism, preoperative localization studies and a focused surgical approach can result in a 95% success rate with minimum complications.

Selective Venous Catheterization and Plasma Catecholamine Analysis in the Diagnosis of Phaeochromocytoma

Selective Venous Catheterization and Plasma Catecholamine Analysis in the Diagnosis of Phaeochromocytoma

Evaluation of Somatostatin as a Plasma Tumor Marker in Medullary Thyroid Carcinoma

Somatostatin (SRIF) immunoreactivity has been frequently reported in tumor tissues of cell types, belonging to the APUD system, including medullary thyroid carcinoma (MTC). However, the value of SRIF as a plasma tumor marker for MTC is controversial. We have measured SRIF plasma levels in 35 patients with different stages of MTC to evaluate the use of SRIF as a plasma tumor marker compared to the current "gold standard" calcitonin (CT). The median SRIF value in healthy controls was 36.5 pg/mL, the upper limit of normal was defined at the controls. The median value was 28 pg/mL (p = 0.37, Mann-Whitney U test). Five patients in the control group and three in the MTC group had SRIF levels that exceed the 95th percentile. SRIF and CT levels correlated only weakly (0.38), as determined by the Spearman rank order correlation test. Pentagastrin stimulation led to a diagnostic increase in SRIF levels in only one of five MTC patients. During selective venous catheterization, diagnostic gradients for CT, allowing tumor localization, could be demonstrated, whereas measurement of SRIF levels did not aid in tumor detection. Although SRIF immunostaining may be valuable as an additional marker in the histochemical diagnosis of MTC, SRIF has no value as a plasma tumor marker in the diagnosis of this disease.