Pediatric recipients of three or more hepatic allografts: results and technical challenges.

BACKGROUND/PURPOSE: Children who require a liver transplant at an early age risk chronic allograft rejection (CAR) and other causes of allograft loss. Multiple retransplants may be required for long-term patient survival. The authors evaluate this approach based on our results and technical difficulties. METHODS: Charts of 7 children who received 3 or more liver transplants from 1989 to the present were reviewed retrospectively. RESULTS: A total of 151 children required liver transplantation at our institution since 1989. Of these, 4 boys and 3 girls (mean age, 6.2 years; range, 3 to 14 years) have received 3 or more allografts. The etiology of liver failure for the penultimate allograft was CAR (n = 6) and hepatic artery thrombosis (HAT; n = 1). Five cases required modification of portal vein or hepatic artery anastomoses. Two patients with vena caval strictures required supradiaphragmatic vena caval reconstruction. The original Roux-en-Y limb was adequate for biliary reconstruction in all cases. Five children currently are alive (survival rate, 71%) with good graft function having had a mean follow-up of 23 months (range, 2 to 48 mos.). CONCLUSIONS: The operative procedure for the multiple hepatic transplant child is challenging. The transplant team must be prepared for intraoperative issues such as extended organ ischemia time during hepatectomy, extensive blood loss, and potential need for creative organ revascularization techniques. Overall, multiple retransplant results are good and justify the use of multiple allografts.

Teratoid Wilms tumor arising as a botryoid growth within a supernumerary ectopic ureteropelvic structure.

We report a case of a teratoid Wilms tumor arising within a supernumerary ectopic ureteropelvic structure in a 7-year-old boy. The tumor was near the right kidney but was completely separate from it. On the contralateral side, the child had a duplication of the ureteral system. Pathologic examination revealed the mass to be completely enveloped by a fibromuscular sac lined by urothelium. The tumor had a botryoid, polypoid architecture and, in addition to areas of classic Wilms tumor, had extensive squamous, mucinous, and columnar elements. Teratoid Wilms tumors are rare and, to the best of our knowledge, have not previously been described as arising either in anomalous urinary structures or at 7 years of age.

Gastrointestinal perforation after pediatric orthotopic liver transplantation.

PURPOSE: The aim of this review was to determine the incidence of gastrointestinal perforation after pediatric liver transplantation and to identify risk factors and clinical indicators that may lead to an earlier diagnosis. METHODS: A retrospective chart review of all children who presented with gastrointestinal perforation after liver transplantation at our institution between January 1, 1987 and August 1, 1996 was performed. RESULTS: One hundred fifty-seven orthotopic liver transplants were performed in 128 children. Fifty-eight reexplorations, excluding those for retransplantation, were performed in 38 children. Ten perforations occurred in six children (incidence, 6.4%). Two children required multiple reexplorations because of several episodes of perforation. The sites of perforation were duodenum (n=1), jejunum (n=8), and ileum (n=1). A single-layer closure was used to repair five perforations, two-layer closures in four, and resection with primary anastomosis in another. The type of repair did not affect the occurrence of subsequent perforations. All the children were less than 18 months old. Four children had undergone prior laparotomy. All children had choledochoenteric anastomoses, but only one had a perforation associated with it. One child sustained bowel injury during the dissection for the liver transplant, but none of the perforations occurred at this site. Bowel function had returned before perforation in five children. Five children were receiving systemic antibiotics at the time of their perforation, and none had been dosed with pulse steroids for rejection. All of the children had significant changes in their temperature. Acute leukopenia developed in one child. A leukocytosis developed in the rest of the children. Abdominal radiographs demonstrated pneumoperitoneum in only one child. All children had positive culture findings from their abdominal drains. Cytomegalovirus developed in one child. Although the diagnosis of gastrointestinal perforation after pediatric liver transplant remains difficult, positive drain culture findings and significant alterations in temperature and leukocyte counts suggest its presence. Pneumoperitoneum is rarely present. CONCLUSION: A high index of suspicion and timely laparotomy, especially in children less than 2 years of age, may be the only way to rapidly diagnose and treat this potentially devastating complication of liver transplant.

Fibrosing colonopathy in children with cystic fibrosis.

PURPOSE: Fibrosing colonopathy is a newly described entity seen in children with cystic fibrosis. The radiological hallmarks are foreshortening of the right colon with varying degrees of stricture formation. High-dose enzyme therapy has been implicated as the cause of this process. The purpose of this study is to review the author's experience with evaluation and treatment of these patients. METHODS: There are currently 380 patients being treated at our CF center. Fifty-five of these patients have been treated with high-dose enzyme therapy (> 5,000 units of lipase/kg). The medical records of these patients, who are at risk for developing fibrosing colonopathy, were reviewed for the presence of recurrent abdominal complaints, and the work-up and treatment of these symptoms. RESULTS: Chronic complaints of abdominal pain, distension, change in bowel habits, or failure to thrive were present in 24 of the 55 patients treated with high-dose enzymes. So far, 18 of these 24 patients have been evaluated by contrast enema. Thirteen of eighteen have been found to have fibrosing colonopathy characterized by foreshortening and strictures of the colon. Additional findings included focal strictures of the right colon (7 of 13), long segment strictures (5 of 13), and total colonic involvement (1 of 13). Nine patients with the most severe symptoms have undergone colon resection, including five segmental right colectomies, three extended colectomies (ileo-sigmoid anastomosis), and one subtotal colectomy with end-ileostomy. Pathological evaluation has shown submucosal fibrosis, destruction of the muscularis mucosa, and eosinophilia. No postoperative complications or deaths occurred. All nine postoperative patients have noted marked symptomatic improvement. Contrast enema follow-up results are available for six patients, and have documented no recurrent strictures to date. Three of four nonoperative patients have less severe symptoms and are currently being treated conservatively. The other family has refused surgery and the patient is being treated symptomatically. CONCLUSION: High-dose lipase replacement has been implicated as the etiology for FC and was present in all of our patients. Our cystic fibrosis center now routinely limits lipase to 2,500 U/kg per dose. We recommend the use of the contrast enemas to evaluate at-risk patients who have chronic abdominal complaints or who present with recurrent bowel obstruction. Colon resection should be performed in those with clinically and radiographically significant strictures with the expectation of a good outcome.

Mesenteric pleomorphic liposarcoma in an adolescent.

We report a case of pleomorphic liposarcoma arising in the root of the mesentery of an adolescent girl. Pleomorphic liposarcoma is an extremely rare tumor in the pediatric age group, and few well-documented cases are found in the literature. To the best of our knowledge, none have been described in the abdomen. The histologic and ultra-structural features of this tumor are described, and the literature concerning pediatric pleomorphic liposarcoma is reviewed.

Paracrine Ca2+ signaling in vitro: serotonin-mediated cell-cell communication in mast cell/smooth muscle cocultures.

Mast cells are tissue-resident immune cells that are capable of signaling many different cell types in vascularized tissue including epithelia and smooth muscle. We have developed an in vitro coculture system in which secretion of serotonin by a mucosal mast cell line (RBL-2H3) can be studied at a single cell level by measuring Ca2+ transients in fura-2 loaded mast cells and serotonin-sensitive A7r5 smooth muscle cells using fluorescence video microscopy and digital image processing. A7r5 cells elevate intracellular Ca2+ via 5HT2 receptors in response to bath-applied serotonin with an ED50 for serotonin of 550nM. Crosslinking IgE receptors with antigen caused Ca2+ transients in the mucosal mast cells. Ca2+ responses in the smooth muscle were detected approximately 30-240 sec after the initiation of the mast cell Ca2+ responses. Smooth muscle Ca2+ responses were dependent on preloading mast cells with serotonin and were blocked by the 5HT2 antagonist ketanserin. The timing and magnitude of the smooth muscle responses indicated that secretion from mast cells can lead to local concentrations of serotonin in the range of 300 nM within 1 min of antigen stimulation. This coculture technique has allowed the first direct demonstration of serotonin-mediated signaling between immune cells and vascular elements.

Rejection after pediatric liver transplantation is not the limiting factor to survival.

Liver transplantation became a very successful therapy when cyclosporin A was introduced as an immunosuppressive agent. In an effort to evaluate the contribution of difficult or uncontrolled allograft rejection to mortality, the authors determined the most important factors that limited survival after liver transplantation. Eighty-two children received a total of 94 liver transplants from January 1987 to the present. Patients' records were reviewed for complications that contributed to morbidity and mortality and to assess which complications were preventable. Twelve patients died (15%), nine within 6 weeks of liver transplantation. The chief contributing cause of death was hepatic artery thrombosis (one patient), brain death after liver transplantation for fulminant hepatic failure (two patients), primary allograft nonfunction or dysfunction (two patients), allograft rejection (three patients), or other problems (four patients). Overall, hepatic artery thrombosis occurred in 3.1%, allograft rejection in 57%, fulminant hepatic failure in 7%, and donor organ dysfunction in 7%. Allograft rejection contributed directly to the cause of death in three children (4%). The authors conclude that few deaths after pediatric liver transplantation are caused by failure of immunosuppression. A high survival rate can be achieved after transplantation by eliminating the correctable complications that most frequently occur in the early postoperative period.

Isolated liver transplantation for liver failure in patients with short bowel syndrome.

The ultimate prognosis for patients with short bowel syndrome (SBS) has become progressively more favorable over the past decade. Advances in long-term total parenteral nutrition (TPN) have allowed this group of patients to meet nutritional needs while the process of intestinal adaptation occurs. Unfortunately, a subgroup of patients with SBS have hepatic failure (HF), most often secondary to TPN-induced cholestasis. Combined small bowel and liver transplantation (LT) offers a sound anatomic solution for cases of HF with SGS, but it remains experimental at this time. We propose that an isolated LT is a viable alternative mode of therapy for the patient with HF and SBS. The following characteristics were reviewed for five patients with SBS and HF who underwent LT: age at transplantation, weight, liver function, survival, intestinal length, volume of feeding before surgery, and current feeding tolerance and liver function. Four boys and one girl, aged 5.5 to 15 months (average, 11.9), had LT. The total bilirubin level at the time of transplantation was 14.4 to 37 mg/dL (average, 24.7). The patients weighed between 3.8 and 12 kg (average, 8.0), and feeding tolerance ranged from no enteric to complete enteric feeding (average, < 33% of calories by enteric feeding). Bowel loss was attributed to necrotizing enterocolitis in two cases, volvulus in two, and birth hypoxia in one. Bowel length ranged from 60 to 120 cm (average, 88.6). Four children (80%) survived LT, and the average follow-up period was 9.3 months. Three (75%) are home; one is on combined hyperalimentation and enteral feeding, and two are on full enteric feeding. One remains in a chronic care facility, on combined enteral and intravenous feeding. The average daily enteral feeding now comprises more than 70% of caloric requirements. The total bilirubin level is .6 to .8 mg/dL (average, .71). Isolated LT for HF in the patient with SBS effectively restores liver function, allowing time for further intestinal adaptation.

Undifferentiated (embryonal) sarcoma arising in conjunction with mesenchymal hamartoma of the liver.

The histogenesis of the undifferentiated (embryonal) sarcoma of the liver has been much debated. Originally, some investigators suggested that the tumor could originate from a mesenchymal hamartoma. Others doubted this hypothesis. The demonstration of alpha-1-antitrypsin in some tumors and of cytokeratins in others gave rise to new theories suggesting that the tumor was either a fibrous histiocytoma or a sarcomatoid hepatocellular carcinoma. As a new development in this search for the genesis of the undifferentiated (embryonal) sarcoma of the liver, this report describes a case that seems to substantiate, for the first time, the original hypothesis histogenetically linking the undifferentiated (embryonal) sarcoma and the mesenchymal hamartoma. The case is that of a 12-yr-old girl who developed an undifferentiated (embryonal) sarcoma of the liver in conjunction with a mesenchymal hamartoma. Furthermore, in places, the tumor exhibited striking epithelial differentiation as well as immunoreactivity for cytokeratins, alpha-1-antitrypsin and vimentin. Immunoreactivity for alpha-fetoprotein was limited to the areas of epithelial differentiation.

Monotherapy with cyclosporine for chronic immunosuppression in pediatric liver transplant recipients.

Children who survive liver transplantation (LT) suffer the adverse effects of life-long immunosuppression. In an attempt to minimize these effects, we have instituted a program of tapering immunosuppression, resulting in chronic monotherapy for children after LT. Seventy-three children ages 4 months to 19 years received LT between January 1987 and December 1992. Patient survival was 85% (62/73), with graft survival of 73%, at one year. Triple therapy with prednisone, cyclosporine, and azathioprine begun at transplant was tapered as follows: 1-2 mg/kg prednisone at discharge was reduced by .2 mg/kg every 2 months until a .2 mg/kg total was reached. Alternate-day steroids (.2 mg/kg) were begun at 1 year and discontinued at 1.5 years. AZA (1 mg/kg) was begun posttransplant and discontinued after any serious viral illness or by 1 year. Currently 37 survivors are > 18 months post-LT and were considered candidates for monotherapy. Monotherapy was attempted in 28 (76%), and 25 of these remain on monotherapy an average of 2 years later. All have normal liver function. After monotherapy and alternate-day steroids were achieved, 66% of children < 5th percentile for height at the time of transplant improved to greater than the 5th percentile. There were 3 (11%) patients who rejected while on monotherapy an average of 1.15 years after it was started. These patients had the following predisposing factors that decreased cyclosporine levels and led to rejection: common bile duct stricture, chronic and intermittent antibiotic administration for urinary tract infection, and noncompliance. In the 9 potential candidates not tapered to monotherapy, 6 have had recurrent acute or chronic rejection; 2 of these now receive FK506. We conclude that the majority of stable pediatric LT recipients may be safely tapered to chronic cyclosporine monotherapy. Increased growth is a major benefit of decreased steroid dosing in these children. Cyclosporine absorption and adequate levels are crucial for success of this approach.

Simple technique for determination of the correct length of percutaneous tunnelled catheters in neonates and children.

A simple technique for determining the correct catheter length in percutaneous tunnelled catheters in infants and young children has been devised that virtually guarantees accurate catheter tip placement. Sixty-six patients, aged newborn to 5 years (mean, 1.6 years) have successfully undergone this technique. It is safe, simple, precise, quick, and cost effective. It requires only a hemostat, a suture, and the supplies provided in the prepackaged catheter kit. This technique should be used whenever a percutaneous technique for accessing the vein is used and fluoroscopy is available.

Calcium signaling in endothelia: cellular heterogeneity and receptor internalization.

The vasoactive factors thrombin, bradykinin (BK), and ATP are released in response to tissue damage and inflammation and act on endothelium to modulate vascular perfusion. We have investigated the second messenger response of endothelium activated by these agonists and, in particular, the mechanism of desensitization to BK. Fura-2 fluorescence ratio imaging of calf pulmonary artery endothelial cells (CPAE) revealed 5- to 10-fold increases on intracellular Ca (Cai) in response to these agents. Maximal doses caused Cai to increase from 52 to 248 nM (thrombin), 556 nM (BK), and 643 nM (ATP). Agonists elicited a rapid (within 30 s) increase of Cai due to release of Ca from intracellular stores followed by a secondary elevation of Cai dependent on entry of external Ca. The temporal characteristics of the Cai responses to all agonists were heterogeneous from cell to cell, and, interestingly, repeated stimulation gave identical signature responses from individual cells, although the amplitude of the Cai response decreased to thrombin and especially bradykinin but not for ATP. This decrease was agonist specific because ATP elicited large increases of Cai after thrombin or BK desensitization. Maximal desensitization was obtained with BK applied for 5-10 min followed by a rest of < 10 min before restimulation. Although desensitization primarily reduced the elevation of Cai due to the release of the internal store, entry of extracellular Ca was also reduced. Cells responded heterogeneously to desensitization in that those with prominent extracellular Ca entry responded most strongly upon a second stimulation with BK. Because desensitized cells still responded to ATP with an increase of Cai, the desensitization was controlled at a step prior to the activation of phospholipase C. Desensitization occurred by a reduction of BK receptor number; a 10-min BK pretreatment reduced [3H]BK binding to receptors by 70% (from 14,600 receptors/cell, Km = 5 nM, to 5,300). As surface receptor numbers decreased, internalized receptors increased as assayed by an acetic acid wash. The time course of the receptor internalization was similar to the decrease in Cai response to BK. We conclude that the vasoactive agonists thrombin, BK, and ATP increase the second messenger Cai in endothelial cells and that a desensitized Cai response occurs with BK, but not with ATP, due to downregulation and endocytosis of the BK receptor.

Successful splenorenal shunt for emergent control of variceal bleeding in a small child.

A 8.6-kg, 10-month-old boy with idiopathic cavernous transformation of the portal vein developed variceal hemorrhage refractory to nonoperative management. A distal splenorenal shunt was performed while the bleeding was controlled with balloon tamponade. Hemorrhage was successfully controlled with no recurrent bleeding and the shunt remains patent at 1 year of follow-up.

Intracellular pH regulation in IEC-6 cells, a cryptlike intestinal cell line.

Regulation of intracellular pH, pHi, was studied using microspectrofluorimetry of the pH-sensitive, fluorescent dye 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein in the rat intestinal crypt cell line, IEC-6. In N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES)-buffered solutions with pHi 7.25, treatment with a pulse of NH4Cl caused cells to acidify and then recover to control level. Because recovery was Na dependent, blocked by 1 mM amiloride, and unaffected by the presence and absence of Cl, it was likely because of a Na+-H+ exchanger. Cells were also acid loaded by changing from HEPES to HCO3-CO2-buffered solutions. pHi again recovered, but 1 mM amiloride reduced the rate of H+ efflux by only 47%. This HCO3-dependent, amiloride-insensitive H efflux required Na+ but not Cl- and was completely blocked by 200 microM [H2] 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS). We conclude that a Na+-HCO3- cotransporter was operative. Cl-free solutions caused pHi to increase from 7.19 to 7.41; this effect required the presence of exogenous HCO3-CO2 but not Na and was blocked by 200 microM [H2]DIDS. A Cl- -HCO3- exchanger is the most likely explanation for these data. All the pHi regulatory mechanisms are operative in NaCl-HCO3-CO2-buffered solutions. The Na+-H+ and Na+-HCO3- mechanisms are acid extruders, whereas the Cl- -HCO3- exchanger is an acid loader. These transporters may be important for generating HCO3 secretion by intestinal crypt cells.

pH regulation in hepatoma cells: roles for Na-H exchange, Cl-HCO3 exchange, and Na-HCO3 cotransport.

Regulation of intracellular pH (pHi) was studied in Fu5, a rat hepatoma cell line that maintains a variety of differentiated functions. Microspectrofluorimetry of the pH-sensitive dye 2',7'-biscarboxyethyl-5(6)-carboxyfluorescein (BCECF) was used to measure pHi in 10-15 cells growing on cover glasses that were mounted in a flow-through chamber on the stage of a microscope. In N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES)-buffered solutions, pHi was 7.14, and intrinsic buffer capacity was inversely related to pHi. Amiloride (0.1 mM) caused pHi to decrease by 0.33 pH units in 4 min. Recovery from an acid load (using either NH4 prepulse technique or Na-free solutions) was completely blocked by amiloride. In HCO3-CO2-buffered solutions, pHi was 7.15, and buffer capacity was relatively insensitive to pHi between pHi of 6.6 and 7.2. Amiloride caused pHi to decrease by only 0.09 units. Recovery from an acid load was Na dependent, occurred in Cl-free solutions, and was totally blocked by the combination of amiloride plus 0.5 mM dihydro-4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (H2DIDS); recovery occurred when either amiloride or H2DIDS was removed. Removal of external Cl caused a rapid, H2DIDS-blockable alkalinization that was faster in HCO3-CO2 than in HEPES. The apparent Km for Clout for relaxation of Cl-free alkalinization was 4.5 mM. Rate of HCO3 transport during Cl-free treatment increased at alkaline resting pHi. It is concluded that Fu5 cells have two Na-dependent base-loading mechanisms and an acid-loading Cl-HCO3 exchanger. In solutions containing HCO3-CO2, the Na-H exchanger accounts for approximately 40% of recovery from an acid load, and a Na-HCO3 cotransporter accounts for the remainder. Recovery from an alkaline load appears to occur through the activity of the Cl-HCO3 exchanger.

Intravenous digital subtraction angiography: its use in evaluating vascular injuries in children.

Angiography is often essential in the evaluation of patients with suspected vascular injuries. However, arterial cannulation has a significant inherent complication rate, especially in small patients. Therefore, a less invasive method of evaluating children with such injuries is desirable. We report nine children (age range, 9 months to 16 years; median, 7 years) in whom intravenous digital subtraction angiography (IV-DSA) was used to evaluate suspected vascular injuries. IV-DSA showed a false aneurysm in two children, one managed by ligation alone and the other by resection with primary anastomosis. One child was found to have an arteriovenous fistula, which was treated by ligation. An iliac occlusion, following an arteriogram to evaluate a liver tumor, was documented by IV-DSA and successfully managed with aggressive anticoagulant therapy. Demonstration of a normal vascular tree avoided exploration in four children. A planned skin flap was abandoned in a child who suffered an electrical injury when IV-DSA showed lack of adequate vascular supply. In all nine cases, the IV-DSA obviated the need for intraarterial angiography. In addition to avoiding arterial cannulation, IV-DSA required significantly less radiation and less time to perform than conventional arteriography. Motion artifact, vessel overlap, and some loss of minute detail are some of its potential shortcomings. IV-DSA is an effective method of screening children with suspected vascular injuries. In addition, our experience has shown that IV-DSA can be the definitive diagnostic procedure, although intraarterial angiography may be necessary in selected cases.

Glucocorticoids confer normal serum/growth factor-dependent growth regulation to Fu5 rat hepatoma cells in vitro. Sequential expression of cell cycle-regulated genes without changes in intracellular calcium or pH.

Glucocorticoid hormones induced a stringent dependence on serum for the in vitro proliferation of Fu5 rat hepatoma cells by suppressing the growth rate and final quiescent cell density. Treatment of dexamethasone-suppressed quiescent Fu5 with serum plus insulin caused a rapid reinitiation of cellular proliferation and DNA synthesis that peaked at 16 h. RNA dot blot analysis of this time course showed that the transcript levels for the proto-oncogenes c-fos, c-myc, and c-rasKi peaked at 0.5, 2, and 4 h, respectively, while expression of c-rasHa and ornithine decarboxylase transcripts rose steadily during 16 h. Microspectrofluorimetric measurements of cytosolic calcium (Ca2+i) with fura-2 showed that insulin and serum, alone or in combination, elicited no changes in Ca2+i over a 50-min time course, although ATP, which is not a mitogen, induced large increases in Ca2+i. Cytosolic pH, pHi, was also measured using 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein. Insulin and serum, alone or in combination, did not cause pHi to increase in either 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) (pHi 7.17)- or HCO3/CO2 (pHi 7.19)- buffered media. Acid-loading of cells with NH4Cl indicated that both quiescent and proliferating Fu5 cells have equally active, amiloride-sensitive Na/H exchangers. Therefore, induction of DNA synthesis and proto-oncogene expression occurs in Fu5 epithelial tumor cells in the absence of any short term increases of pHi or Ca2+i.

Respiratory complications in cervical thymic cysts.

Thymic cysts are considered uncommon lesions in the differential diagnosis of pediatric neck masses. They have been described as asymptomatic and of little clinical consequence. Recent reports have stressed the possibility of respiratory compromise associated with these lesions. We reviewed our experience with cervical thymic cysts with emphasis on respiratory problems. Ten pediatric patients underwent surgery and were found to have cervical thymic cysts. Ages ranged from newborn to 14 years. There were four boys and six girls. Two were found to have the thymic cysts at time of neck exploration for Grave's disease and hyperparathyroidism. Of the remaining eight patients, all had mobile cystic masses, located anterior to but extending beneath the lower third of the sternocleidomastoid muscle. The size of the mass ranged from 3.0 to 8.5 cm. Preoperative diagnosis included cystic hygroma/branchial cleft cyst (five), lymphoma (one), teratoma (one), and thymic cyst (one). All had a history of rapidly developing neck mass. Seven of the eight gave a history of upper respiratory tract infection (URI) prior to the development of the mass. Five had imaging studies that showed tracheal compression. Three of these required airway management in the early postoperative period. All were excised through a neck incision, with two requiring sternal extension. Histology showed cholesterol crystals, Hassall's corpuscles, and giant cell reaction diagnosis of thymic cysts. There has been no recurrence and no permanent respiratory sequela in the ten patients. Cervical thymic cysts are benign lesions that may be more common than literature suggests.(ABSTRACT TRUNCATED AT 250 WORDS)