[Video-assisted parathyroidectomy in the management of patients with primary hyperparathyroidism]

INTRODUCTION

In recent years, different minimally invasive techniques of parathyroidectomy have been described. We performed a retrospective study to evaluate the indications and results of video-assisted parathyroidectomy (Vap) in the management of our patients with primary hyperparathyroidism (PHPT).

MATERIALS AND METHODS

During the last 5 years (1998-2002), we operated on 528 patients with PHPT. Vap was proposed for patients with sporadic PHPT, without associated goiter and without previous neck surgery, in whom a single adenoma was localized by means of sonography and/or sestamibi scanning. Vap was performed by lateral approach with insufflation for patients with adenoma located deeply in the neck and by gasless midline approach for patients with adenoma located anteriorly. A quick parathyroid (qPTH) assay was used during the surgical procedures. Calcemia, phosphoremia and PTH were systematically evaluated in patients on days 1 and 8, 1 month and 1 year after surgery. All patients underwent pre-operative and postoperative investigations of vocal cord movements.

RESULTS

Among 528 patients with PHPT, 228 (43%) were not eligible for Vap: associated nodular goiter (99 cases), previous neck surgery (42 cases), suspicion of multiglandular disease (25 cases), lack of pre-operative localization (48 cases), and miscellaneous causes (14 cases). Vap was performed in 300 patients with sporadic PHPT: 282 lateral access, 17 midline access and 1 thoracoscopy. Median operative time was 50 min (20-130 min). Conversion to conventional parathyroidectomy was required in 42 patients (14%): missed adenomas (11 cases), difficulties of dissection (7 cases), multiglandular disease correctly predicted by qPTH (10 cases); qPTH assay false negative results (3 cases), sestamibi scan false positive results (10 cases) and 1 sonography false positive result. One patient presented definitive recurrent nerve palsy. One patient had a persistent PHPT and one other patient had a recurrent PHPT.

CONCLUSION

Vap can be proposed for more than half of patients with PHPT. In our experience Vap and conventional parathyroidectomy are complementary. Immediate results of Vap are similar to those obtained with conventional parathyroidectomy but no conclusions can be drawn in terms of influence of Vap on the outcome of the patients operated for PHPT.

[Video-assisted minimally invasive parathyroidectomy with lateral approach in patients with primary hyperparathyroidism]

INTRODUCTION

Different minimally invasive techniques of parathyroidectomy have been described. We performed a retrospective study to evaluate the indications and results of video-assisted parathyroidectomy (VAP) in the management of patients with primary hyperparathyroidism (PHPT).

MATERIALS AND METHODS

Between 1998 and 2002, 528 patients were operated on because PHPT. VAP was proposed for patients with sporadic PHPT, without associated goiter and previous neck surgery, in whom a single adenoma was localized. VAP was performed by lateral approach with insufflation for patients with adenoma located deeply in the neck and by gasless midline approach for anteriorly located adenomas. A quick parathyroid (qPTH) assay was used during the surgical procedure. Calcemia, phosphoremia and PTH were systematically evaluated after surgery.

RESULT

Of 528 patients with PHPT, 228 (43%) were not eligible for VAP because associated nodular goiter (99 cases), previous neck surgery (42 cases), suspicion of multiglandular disease (25 cases), lack of preoperative localization (48 cases), and miscellaneous causes (14 cases). VAP was performed in 300 patients with sporadic PHPT: 282 lateral access, 17 midline access and one thoracoscopy. Mean operative time was 50'. Conversion to conventional parathyroidectomy was required in 14% of cases. One patient presented a definitive recurrent nerve palsy. One persistent and one recurrent PHPT were observed.

CONCLUSION

VAP can be proposed for patients with PHPT. Immediate results of VAP are similar to those obtained with conventional parathyroidectomy; no conclusions can be drawn in terms of influence of VAP on the outcome of the patients operated for PHPT.

Specific pattern of RAS oncogene mutations in follicular thyroid tumors

The prevalence of H-RAS, K-RAS, and N-RAS gene mutations in thyroid tumors according to malignancy and histology is controversial. Differences in methodology and histological classifications may explain discrepant results. To address this issue, we first performed a pooled analysis of 269 mutations garnered from 39 previous studies. Mutations proved significantly less frequent when detected with direct sequencing than without (12.3% vs. 17%). The rate of mutation involving N-RAS exon 1 (N1) and K-RAS exon 2 (K2) was less than 1%. Mutations of codon 61 of N-RAS (N2) were significantly more frequent in follicular tumors (19%) than in papillary cancers (5%) and significantly more frequent in malignant (25%) than in benign (14%) tumors. H-RAS mutations in codons 12/13 (H1) were found in 2-3% of all types of tumors, but H-RAS mutations in codon 61 (H2) were observed in only 1.4% of tumors, and almost all of them were malignant. K-RAS mutations in exon 1 were found more often in papillary than follicular cancers (2.7% vs. 1.6%) and were sometimes correlated with special epidemiological circumstances. The second part of this study involved analysis of 80 follicular tumors from patients living in Marseille (France) and Kiev (Ukraine). We used direct sequencing after PCR amplification of exons 1 and 2 of the three RAS genes. Common and atypical adenomas were separated using strict cytological criteria. Mutations of H1-RAS were found in 12.5% of common adenomas and one follicular carcinoma (2.9%). Mutations of N2-RAS occurred in 23.3% and 17.6% of atypical adenomas and follicular carcinomas, respectively. These results confirm the predominance of N2-RAS mutations in thyroid follicular tumors and their correlation with malignancy. They support the implication of N2-RAS mutations in the malignant progression of thyroid follicular tumors and the assumption that some atypical adenomas are precursors of follicular carcinomas.

The ‘false’ non-recurrent inferior laryngeal nerve

Background

A communication between the middle cervical sympathetic ganglion (MCSG) and the inferior laryngeal nerve (ILN) has been described. The anastomotic branch (sympathetic–inferior laryngeal anastomotic branch; SILAB) is usually thin, but is sometimes larger and has the same diameter as the ILN. The purpose of this study was to evaluate prospectively the frequency of this condition and its implications during neck exploration.

Methods

From November 1998 to October 1999, 791 neck explorations were performed: 677 for thyroid, 99 for parathyroid and 15 for concomitant lesions. Some 1253 ILNs were dissected: 656 (52·3 per cent) on the right and 597 (47·7 per cent) on the left side.

Results

The ILN was identified in all cases. On the right side a non-recurrent ILN (NRILN) was found in three patients (0·5 per cent) and a large SILAB in ten (1·5 per cent). No anomalous branch was found on the left side. The SILAB originated from the superior cervical sympathetic ganglion (SCSG) in two patients and directly from the sympathetic chain (SC) above the MCSG in eight. No branch originating from the MCSG was found. The SILAB connected with the ILN less than 2 cm from the cricoid in all patients.

Conclusion

The SILAB may originate not only from the MCSG but also from the SCSG and directly from the SC. When the SILAB is as large as the ILN, it could be mistaken for a NRILN. Before concluding that the anomalous branch is a NRILN, one should check if it originates from the vagus or from the cervical sympathetic system. Awareness of this anatomical condition during neck exploration may help the surgeon to avoid injuries of an ILN running in the usual pathway.

[Multiple endocrine neoplasia type I or Werner syndrome. What is important to know about surgery of a rate disease]

Multiple endocrine neoplasia type 1 (MEN1) is a rare but misleading disease. The diagnosis is evocated when two main lesions are present (parathyroid, endocrine pancreas, pituary gland) but also when a family tree shows recurrent lesions. Other lesions must be taken into account (adrenal glands, neuroendocrine thymic or bronchic lesions, cutaneous lesions, lipomas, nervous central system tumors). Any surgical cure without knowing the MEN1 background leads to failure. Specific treatment of each lesion is reviewed. Genetic diagnosis is possible but the mutation is not found in all cases. Nevertheless, when the mutation is known in a family, a negative genetic test allows to exclude the disease. Prognosis is related to hepatic metastases and to thymic neuroendocrine tumors which are rare (2.1%) but aggressive. As a general rule, any apparently isolated endocrine lesion such hyperparathyroidism must prompt the surgeon to look for another endocrine lesion and to look for an abnormal family tree with recurent monoglandular or pluriglandular lesions.

[Lessons learned from 274 laparoscopic adrenalectomies]

AIMS

To define the role of minimally invasive video-assisted surgery in the surgical management of adrenal disease and discuss the respective indications of the trans and retroperitoneal video assisted approaches.

MATERIALS AND METHODS

During the last 8 years (1994-2001), 330 adrenalectomies were performed in 305 patients: 274 (83%) laparoscopic approaches and 56 (17%) open approach. Open surgery was reserved for patients presenting with large or malignant tumours (29 cases), multiple and/or extraadrenal phaeochromocytomas (13 cases), previous intraabdominal intestinal surgery (10 cases), and in those requiring concomitant intraabdominal surgery (4 cases). Laparoscopic adrenalectomy was performed using the lateral transperitoneal approach for 89 Conn's syndrome, 67 Cushing's syndrome, 2 virilizing tumours, 51 phaeochromocytomas and 65 non secretory tumours greater than 4 cm in diameter. Nineteen patients underwent bilateral adrenalectomy.

RESULTS

There were no deaths. Twenty patients (7.3%) had a complication. Eleven cases required open conversion (4%) because of difficulties with dissection (8 cases), preoperative suspicion of malignancy (2 cases), and one pneumothorax. The average size of tumours was 34 mm (7-110 mm). There were 18 malignant tumours (6.5%): 8 adrenocortical carcinomas, 1 leiomyosarcoma, and 9 metastases. All patients with hormonally secreting tumours were cured of their endocrinopathy. There was 1 death secondary to hepatic metastases in a patient with an adrenocortical carcinoma.

CONCLUSION

Most adrenal tumours are suitable for video assisted excision. The only absolute contraindication is an invasive carcinoma requiring an extended excision. The lateral, transperitoneal approach is the most suitable for tumours greater than 5-6 cm in diameter. Both the transperitoneal or retroperitoneal approaches are suitable for smaller tumours depending on operator choice and experience. However in the presence of a large right lobe of liver or previous intraabdominal surgery the retroperitoneal approach may be preferable.

Results of laparoscopic adrenalectomy for large and potentially malignant tumors

Endoscopic adrenalectomy is the procedure of choice for patients with small functioning adrenal tumors. For most surgeons invasive adrenal carcinoma is an absolute contraindication for laparoscopic adrenalectomy (LA). Whether LA should be proposed for large (> 6 cm), potentially malignant tumors is questionable. The aim of this study was to evaluate the risks and outcome of LA performed in our department in patients with tumors > 6 cm and potentially malignant. We performed a retrospective study of 216 patients who underwent 233 LAs in our department from 1994 to 2000. We selected 19 patients with a tumor > 6 cm and potentially malignant: 8 nonfunctional tumors, 4 cortisol-secreting tumors, 1 virilizing tumor, and 6 pheochromocytomas. In none of these patients did preoperative investigations demonstrated invasive carcinoma. The median tumor size was 70 mm. LA was performed by a transperitoneal flank approach. Conversion to open adrenalectomy was performed in two patients owing to intraoperative evidence of invasive carcinoma. The median operating time was 150 minutes (range 95-240 minutes). Capsular disruption occurred during the dissection of two pheochromocytomas. There was no postoperative morbidity. Six patients had an adrenocortical carcinoma on pathologic diagnosis: three of the eight nonfunctional tumors, one of the four cortisol-secreting tumors, and one virilizing tumor. One patient presented with liver metastases 6 months after surgery and died. The five other patients are disease-free with a follow-up ranging from 8 to 83 months. The 13 patients with benign lesions (6 cortical adenomas, 1 ganglioneuroma, 6 pheochromocytomas) are disease-free with a median follow-up of 47 months (range 10-81 months). In experienced hands LA can be proposed for large, potentially malignant tumors. Conversion to open adrenalectomy should be performed if local invasion is observed during surgery. At present the risk of intraabdominal recurrence is unknown.

Can sporadic medullary thyroid carcinoma be biochemically predicted? Prospective analysis of 66 operated patients with elevated serum calcitonin levels

Measuring serum calcitonin (CT) in patients with thyroid diseases allows preoperative diagnoses of sporadic medullary thyroid carcinoma (MTC) and C-cell hyperplasia (CCH). The aim of this prospective study was to distinguish biochemically between CCH and MTC. Basal CT (bCT) was determined in 7276 consecutive patients referred for thyroid disease. Patients with recurrent, persistent, or familial MTC were excluded. When bCT was > 10 pg/ml a pentagastrin-stimulated CT (sCT) assay was performed. Patients were routinely operated on when bCT > 30 pg/ml or sCT > 100 pg/ml or when other indications for surgery were present. An extensive search for CCH or microscopic MTC was conducted by immunochemistry. Pathologic findings were correlated with the bCT and sCT values. In this study 66 patients were included. No morphologic alterations of C-cells were observed in 5 patients; 16 patients presented with CCH and 45 with MTC. Statistical analysis revealed a correlation of sCT and overall bCT with tumor size and staging (p <0.001). Considering cutoff values for bCT of < or = 30 pg/ml and for sCT of < or = 200 pg/ml, the positive predictive value of the test to detect MTC was 100% and the negative predictive value 63%. No patients with MTC at stage 2 to 4 had bCT <30 pg/ml or sCT <200 pg/ml. A bCT value of < or = 30 pg/ml or sCT < or = 200 pg/ml (or both) is highly predictive of MTC, requiring total thyroidectomy with lymph node dissection. Values of bCT <30 pg/ml and sCT <200 pg/ml do not distinguish between CCH and MTC at stage 1. In this case total thyroidectomy at least is recommended, and the role of nodal dissection might be discussed.

[Thyrotoxic hypokalemic periodic paralysis. Report of three cases]

AIM OF THIS STUDY

Hypokaliemic thyrotoxic periodic paralysis (HTPP) is an uncommon complication of hypothyroidism. Mostly described among Asian patients, it is rare in the other ethnic groups, in particular in caucasians people. Among the possible mechanisms, modification of potassic flows in relation to anomalies of the sodium-potassium pump were evoked.

PATIENTS AND METHOD

We present the cases of three caucasians patients operated on for HTPP. These patients had all previous history of several paretic episodes. The flask paralytic attacks occurred in a brutal way or were preceded by diffuse myalgias. They reached the proximal muscles, especially in inferior limbs. No patient had any respiratory complications. These three patients underwent total thyroidectomy to treat the symptoms of HTPP.

RESULTS

In the three cases, a total thyroidectomy allowed the recovery of the symptoms. After a four years average period of post-operative follow-up, no patient presented any repetition of HTPP. The hyperthyroidism is the cause of decompensation of the molecular anomaly.

CONCLUSION

In our opinion, surgical treatment (total thyroidectomy) is needed in order to reduce the potential gravity of this pathology.

Primary hyperparathyroidism in MEN 1--how radical should surgery be?

Primary hyperparathyroidism is the most common manifestation of MEN 1 syndrome. The management of these patients is complex due to the underlying disease process, which predisposes patients to persistent and recurrent disease. The surgical treatment of patients with MEN 1 and hyperparathyroidism can therefore be considered to be palliative in nature. The basic principles of surgery include (1) obtaining and maintaining normocalcaemia for the longest time possible, avoiding persistent/recurrent hypercalcaemia, (2) avoiding surgically induced hypocalcaemia, and (3) facilitating future surgery for recurrent disease. Two approaches have been described as the best practice for patients with hyperparathyroidism in MEN 1: subtotal parathyroidectomy, leaving a remnant of no more than 60 mg in the neck, and total parathyroidectomy with immediate autotransplantation of 10-20 1 mm(3) pieces of parathyroid tissue. Both approaches should be combined with efforts to exclude supernumerary glands and ectopic parathyroid tissue by including resection of fatty tissue from the central neck compartment and thymectomy in all patients. Cryopreservation of parathyroid tissue should be performed whenever facilities are available. In patients with persistent or recurrent disease, an attempt to obtain total elimination of cervical parathyroid tissue is justified, combined with cryopreservation of parathyroid tissue. As radical as surgery is for hyperparathyroidism in MEN 1, the surgeon must take steps to avoid permanent hypoparathyroidism, which in young patients may be worse than the disease itself.

Indications and results of video-assisted parathyroidectomy by a lateral approach in patients with primary hyperparathyroidism

BACKGROUND

Different minimally invasive techniques of parathyroidectomy have been described. We performed a retrospective study to evaluate the indications and results of video-assisted parathyroidectomy by lateral approach (VAPLA) in the management of our patients with primary hyperparathyroidism (PHPT).

METHODS

From December 1997 to December 2000, we operated on 293 patients with PHPT. VAPLA was proposed for patients with sporadic PHPT in whom a single adenoma was localized by means of sonography or sestamibi scanning, or both. VAPLA was performed on the anterior border of the sternocleidomastoid muscle. A quick parathormone (PTH) assay was used during the surgical procedures.

RESULTS

Of the 293 patients, 127 (43.3%) were not eligible for VAPLA: ipsilateral previous neck surgery (28 cases), associated nodular goiter (59 cases), suspicion of multiglandular disease (15 cases), no preoperative localization (17 cases), and miscellaneous causes (8 cases). VAPLA was performed in 166 patients (56.7%). Conversion to conventional parathyroidectomy was required in 26 patients (15.6%). Morbidity included 2 local hematomas, 1 definitive recurrent nerve palsy, and 4 capsular fractures. All of the 166 patients were normocalcemic, with follow-up ranging from 3 to 33 months.

CONCLUSIONS

VAPLA is safe and effective. It should be reserved for patients with sporadic PHPT, with a small single adenoma clearly localized preoperatively.

The pattern of intestinal substrate oxidation is altered by protein restriction in pigs

BACKGROUND & AIMS

Previous studies indicate that amino acids and glucose are the major oxidative substrates for intestinal energy generation. We hypothesized that low protein feeding would lower the contribution of amino acids to energy metabolism, thereby increasing the contribution of glucose.

METHODS

Piglets, implanted with portal, arterial, and duodenal catheters and a portal flow probe, were fed isocaloric diets of either a high protein (0.9 g/[kg/h] protein, 1.8 g/[kg/h] carbohydrate, and 0.4 g/[kg/h] lipid) or a low protein (0.4 g/[kg/h] protein, 2.2 g/[kg/h] carbohydrate, and 0.5 g/[kg/h] lipid) content. They received enteral or intravenous infusions of [1-13C]leucine (n = 17), [U-13C]glucose (n = 15), or enteral [U-13C]glutamate (n = 8).

RESULTS

CO2 production by the splanchnic bed was not affected by the diet. The oxidation of leucine, glutamate, and glucose accounted for 82% of the total CO2 production in high protein-fed pigs. Visceral amino acid oxidation was substantially suppressed during a low protein intake. Although glucose oxidation increased to 50% of the total visceral CO2 production during a low protein diet, this increase did not compensate entirely for the fall in amino acid oxidation.

CONCLUSIONS

Although low protein feeding increases the contribution of enteral glucose oxidation to total CO2 production, this adaptation is insufficient. To compensate for the fall in amino acid oxidation, other substrates become increasingly important to intestinal energy generation.

Video-assisted parathyroidectomy via the lateral approach vs conventional surgery in the treatment of sporadic primary hyperparathyroidism: results of a case-control study

BACKGROUND

We previously demonstrated that minimally invasive video-assisted parathyroidectomy (VAP) can be performed via a lateral approach on the line of the sternocleidomastoid muscle. The aim of this study was to compare the results of this technique with those of conventional parathyroidectomy (CP) in a case-control study.

METHODS

Over a 2-year period, 80 VAP were attempted. The selection criteria were as follows: sporadic primary hyperparathyroidism, no history of previous neck surgery, no thyroid disease, suggestion of a single adenoma on preoperative imaging. A rapid intraoperative parathyroid hormone (PTH) assay was performed. The procedure was completed successfully in 68 patients. A case-control study of 68 patients who underwent CP for a single adenoma was performed. The controls were matched for age and sex.

RESULTS

All of the patients were normocalcemic at follow-up. No statistically significant differences between the VAP and the control groups were found for age, sex, pre- and postoperative calcemia and PTH, adenoma weight, operating time, complication rate, or postoperative stay. One VAP patient developed recurrent laryngeal nerve palsy. Patients who underwent VAP required less analgesics (p < 0.0001) and were more satisfied with the cosmetic results (p < 0.0001).

CONCLUSIONS

This study suggests that VAP by the lateral approach has some advantages over CP in terms of postoperative pain and cosmetic results.

Normocalcemia with elevated parathyroid hormone levels after surgical treatment of primary hyperparathyroidism

BACKGROUND

Thirty percent of patients who undergo successful parathyroidectomy for primary hyperparathyroidism show unexplained elevated postoperative serum parathyroid hormone (PTH) levels despite normocalcemia.

METHODS

PTH levels were measured monthly in 97 patients for 6 months after parathyroidectomy. Renal function, 25-OH-vitamin D levels, serum alkaline phosphatase levels, osteocalcin, and bone densitometry were evaluated before and 6 months after surgery. PTH reactivity to calcium loading was tested at the sixth month.

RESULTS

Thirty patients had elevated PTH levels despite normocalcemia after parathyroidectomy. Before surgery, these 30 patients had higher PTH and creatinine levels, lower vitamin D levels, and more extensive bone involvement than those with normal postoperative PTH levels. In patients with normal renal function and normal vitamin D levels, postoperative PTH values correlated with preoperative PTH levels but not with bone disease.

CONCLUSION

In most cases, elevated PTH levels after surgery is an adaptive reaction to renal dysfunction or vitamin D deficiency. If no adaptive cause can be found, persistent hyperparathyroidism must be suspected.

Adrenocortical carcinomas: surgical trends and results of a 253-patient series from the French Association of Endocrine Surgeons study group

Because of the rarity of adrenocortical carcinoma, survival rates and the prognosis for patients who have undergone operation are not well known. The purpose of the French Association of Endocrine Surgery was to evaluate these factors over an 18-year period. A trend study was associated to assess changes in the clinical and biochemical presentations as well as the surgical evolution. A total of 253 patients (158 women, 95 men) with a mean age of 47 years were included. Cushing syndrome was the main clinical presentation (30%), and hormonal studies revealed secreting tumors in 66% of the cases. Altogether, 72% (n = 182) of patients underwent resection for cure, and 41.5% (n = 105) of them had an extensive resection because of metastatic cancer. A lymphadenectomy was performed in 32.5% (n = 89) of the cases. The operative mortality was 5.5% (n = 14). Patients were given mitotane as adjuvant therapy in 53.8% of the cases (n = 135). The results of staging were stage I in 16 patients (6.3%), stage II (local disease) in 126 patients (49.8%), stage III (locoregional disease) in 57 patients (22.5%), and stage IV (metastases) in 54 patients (21.3%). Neither tumor staging nor the rate of curative surgery changed during the study period. More subcostal incisions were performed, and the use of mitotane increased significantly. The 5-year actuarial survival rates were 38% overall, 50% in the curative group, 66% for stage I, 58% for stage II, 24% for stage III, and 0% for stage IV. Multivariate analysis showed that mitotane benefited only the group of patients not operated on for cure. A better prognosis was found in patients operated on after 1988 (p = 0.04), in those with precursor-secreting tumors (p = 0.005), and in those at local stages of the disease (p = 0.0003). Thus mitotane benefited only patients not operated on for cure. Curative resection, precursor secretion, recent diagnosis, and local stage were favorably associated with survival.

Minimally invasive adrenal surgery

The adrenals can be approached endoscopically using either transperitoneal or retroperitoneal access, most surgeons favouring the transperitoneal flank approach with the patient in the lateral decubitus position. Endoscopic retroperitoneal adrenalectomy can be performed via either a posterior or a lateral approach. The main advantage of the retroperitoneal approach in the prone position is that it allows bilateral adrenalectomy without repositioning the patient. Although technically more demanding, endoscopic adrenalectomy provides clear advantages over open procedures for tumours less than 5-6 cm in diameter. The small working space provided by the retroperitoneal approach is a contra-indication for the dissection of tumours over 5-6 cm in diameter. Peritoneal adhesions caused by previous abdominal surgery or a large right lobe of the liver may contra-indicate transperitoneal access. For small benign tumours, the transperitoneal and retroperitoneal routes are safe and effective, and there is no clear advantage of one procedure over the other. Invasive adrenal carcinoma is an absolute contra-indication for endoscopic adrenalectomy. Whether large (>5-6 cm) and potentially malignant tumours should be removed laparoscopically remains debatable.

[Hyperparathyroidism induced by lithium. A new case]

INTRODUCTION

Lithium salts, used for the first time in 1949, had proved to be a highly effective preventive measure in bipolar illness. The first report of lithium-induced hyperparathyroidism was suggested by Garfinkel et al. in 1973. About 40 cases have been reported since, suggesting an enhancement of occurrence of hyperparathyroidism in patients cured by lithium carbonate. We report here a new case discovered by a systematic measurement of calcemia after a surgical intervention for a hip joint prosthesis.

EXEGESIS

Unusual metabolic features associated with this case of hyperparathyroidism include low urinary calcium excretion, normal cyclic AMP excretion and lack of calcic nephrolithiasis. The mechanism probably results from lithium linking with the calcium receptor on the parathyroid and then stimulating PTH secretion. In the same way it could enhance the tubular reabsorption of urinary calcium. Lithium withdrawal is often inefficient in clinical and laboratory test abnormalities and surgery is usually required.

CONCLUSION

It is very important to recognise this particular secondary effect of lithium therapy because clinical symptoms of hypercalcemia can simulate a worsening of the bipolar illness.

Lactase synthesis is pretranslationally regulated in protein-deficient pigs fed a protein-sufficient diet

The in vivo effects of protein malnutrition and protein rehabilitation on lactase phlorizin hydrolase (LPH) synthesis were examined. Five-day-old pigs were fed isocaloric diets containing 10% (deficient, n = 12) or 24% (sufficient, n = 12) protein. After 4 wk, one-half of the animals in each dietary group were infused intravenously with [(13)C(1)]leucine for 6 h, and the jejunum was analyzed for enzyme activity, mRNA abundance, and LPH polypeptide isotopic enrichment. The remaining animals were fed the protein-sufficient diet for 1 wk, and the jejunum was analyzed. Jejunal mass and lactase enzyme activity per jejunum were significantly lower in protein-deficient vs. control animals but returned to normal with rehabilitation. Protein malnutrition did not affect LPH mRNA abundance relative to elongation factor-1alpha, but rehabilitation resulted in a significant increase in LPH mRNA relative abundance. Protein malnutrition significantly lowered the LPH fractional synthesis rate (FSR; %/day), whereas the FSR of LPH in rehabilitated and control animals was similar. These results suggest that protein malnutrition decreases LPH synthesis by altering posttranslational events, whereas the jejunum responds to rehabilitation by increasing LPH mRNA relative abundance, suggesting pretranslational regulation.

[Immunodetection of thyroid peroxidase in the diagnosis of follicular variants of thyroid papillary cancer]

STUDY AIM

The aim of this retrospective study was to assess the role of thyroid peroxidase immunodetection in the cytological diagnosis of follicular variants of thyroid papillary cancer (FVTPC) which are difficult to identify by standard cytology.

PATIENTS AND METHODS

Between 1991 and 1998, 3,505 thyroid fine needle aspiration biopsies were performed by thyroid peroxidase immunocytochemistry and 1,576 patients were operated on. Out of a total of 227 thyroid papillary cancers (TPC), 42 (18.5%) were diagnosed as FVTPC. The results of standard cytology and thyroid peroxidase immunodetection were compared with the histological findings.

RESULTS

The rate of false negatives for TPC in standard cytology was 11% (25/227 cases), with 40% of these false negatives being FVTPC; ten out of 42 (23.8%) cases of FVTPC were not identified by standard cytology. However, cytology with thyroid peroxidase immunodetection diagnosed 224 out of the 227 TPC (99%), and all the FVTPC were correctly identified (100%).

CONCLUSION

FVTCP are the most frequent source of false negatives in standard cytology. Thyroid peroxidase immunodetection allows most of these errors to be avoided, and correctly identifies 99% of TPC including FVTPC.

Pheochromocytoma in multiple endocrine neoplasia type 2: a prospective study

OBJECTIVE

The aim of this prospective study is to update our knowledge of the chronology of pheochromocytoma occurrence in multiple endocrine neoplasia type 2 (MEN 2), and to better manage MEN 2 patients after the genetic diagnosis.

DESIGN

Eighty-seven non-index gene carrier MEN 2 patients were included in this prospective study: 84 patients with MEN 2A (from 52 families) and 3 with MEN 2B (from 3 families).

METHODS

Medullary thyroid carcinoma (MTC) was diagnosed by measuring plasma calcitonin in basal conditions or after pentagastrin stimulation. The search for pheochromocytoma consisted of clinical evaluation, 24 h determination of urinary catecholamines and adrenal imaging. The mean age at genetic diagnosis of MEN 2 was 14.0+/-7.0 years, the mean duration for the follow-up was 7.6+/-2.8 years.

RESULTS

All 87 patients had a MTC detected at the same time as the genetic diagnosis was made. Urinary catecholamine measurements led to the diagnosis of pheochromocytoma and a combination of imaging techniques enabled the correct localization of both unilateral or bilateral adrenal involvement. Pheochromocytoma was detected simultaneously with MTC in only seven patients, and seven others were detected throughout the follow-up. Of the 14 patients with pheochromocytoma, 11 had bilateral involvement: nine were initially bilateral and two became so during follow-up.

CONCLUSION

This study demonstrates that in MEN 2, MTC is the lesion which appears earliest. Pheochromocytoma develops later during the evolution of the disease, and necessitates regular clinical and biological monitoring throughout follow-up. Determination of urinary and/or plasma catecholamines and metanephrines should be performed to detect pheochromocytoma. Imaging techniques lead to the detection of both unilateral and bilateral pheochromocytoma, thus making video-assisted laparoscopic adrenalectomy possible.

[Intravagal parathyroid ectopia]

AIM OF THE STUDY

The presence of an ectopic parathyroid gland is the commonest cause of persistent hyperparathyroidism (HPT). High cervical ectopic glands represent 0.21 to 9% of these cases. Only 3 cases of high intravagal sites have been described. The authors report two new cases of persistent HPT caused by an intravagal parathyroid gland.

PATIENTS AND METHOD

In a series of 1,712 cases of HPT operated over the last 25 years (1,307 primary HPT and 405 secondary or tertiary HPT), two cases (0.12%) of persistent HPT were caused by a high intravagal parathyroid gland. One case corresponded to primary HPT and the other case corresponded to tertiary HPT. One patient underwent three operations and the other patient underwent four operations.

CONCLUSION

Intravagal thyroid tissue may cause HPT. This very rare site must be considered among the other high cervical ectopic sites in the pre- and intraoperative assessment of hyperparathyroidism, particularly in cases of persistent or recurrent hyperparathyroidism.

The "false" nonrecurrent inferior laryngeal nerve

BACKGROUND

Communicating branches between the cervical sympathetic system and the inferior laryngeal nerve (ILN) have been described. They usually originate from the middle cervical sympathetic ganglion (MCSG). These branches (sympathetic-inferior laryngeal anastomotic branch [SILAB]), usually thin, sometimes have the same diameter as the ILN. In this study we prospectively evaluated the frequency of this condition and its implications during surgical neck exploration.

METHODS

From November 1998 to October 1999, 791 patients underwent surgical neck exploration, and 1253 ILNs were dissected: 656 on the right side (52.3%) and 597 on the left side (47.7%).

RESULTS

On the right side, a nonrecurrent ILN was found in 3 cases (0.46%), and a large SILAB was found in 10 cases (1.5%). The SILAB originated from the superior cervical sympathetic ganglion in 2 cases and directly from the sympathetic trunk above the MCSG in 8 cases. No anomalous branch was found on the left side.

CONCLUSIONS

The SILAB may originate not only from the MCSG but also from the superior cervical sympathetic ganglion or directly from the sympathetic trunk. When the SILAB is as large as the ILN, it could be mistaken for a nonrecurrent ILN. The awareness of this anatomic condition during neck dissection may help to avoid injuries of the genuine ILN running in the usual pathway.