Lymphangiogenesis-mediated shedding of LAM cell clusters as a mechanism for dissemination in lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) affects exclusively women of reproductive age, involves the lungs and axial lymphatic system, and is frequently complicated with renal angiomyolipomas. LAM lesions are generated by the proliferation of LAM cells with mutations of one of the tuberous sclerosis complex (TSC) genes. Recent studies indicate that LAM cells can migrate or metastasize to form new lesions in multiple organs, although they show a morphologically benign appearance. In the previous study, we reported LAM-associated lymphangiogenesis and implicated its role in the progression of LAM. In this study, we further focused on the lymphatic abnormalities in LAM: LAM-associated chylous fluid (5 pleural effusion and 2 ascites), surgically resected diaphragm (1 patient), and axial lymphatic system including the thoracic duct, lymph nodes at various regions, and diaphragmatic lymphatic system (5 autopsy cases). We demonstrated that LAM cell clusters enveloped by lymphatic endothelial cells (LCC) in all chylous fluid examined. We identified LAM lesion in the diaphragm (2 of 5 autopy cases and one surgical specimen), thoracic duct (5 of 5), and lymph nodes (retroperitoneal (5 of 5), mediastinal (4 of 5), left venous angle (5 of 5) with total positive rate of 68% to 88% at each region of the lymph node, but less frequent or none at remote lymph nodes located away from the axial lymph trunk (cervical [1 of 5] and axillary [0 of 5]). LCCs were identified in intra-LAM lesional lymphatic channels where LAM cells proliferate along lymphatic system. In in vitro culture system, LCC can fragment into each proliferating LAM cell. These findings suggest that LAM-associated lymphangiogenesis demarcates LAM lesion into bundle- or fascicle-like structure and eventually shed LCC into the lymphatic circulation and that LCCs play a central role in the dissemination of LAM lesion.     

Chylothorax

PHYSIOLOGY: Chylothorax corresponds to the intrathoracic presence of chyle. Chyle is a lymph of intestinal origin containing the product of digested fat. This lymph joins the blood circulation through the thoracic duct. The thoracic duct receives a part of the lymphatic drainage from the viscera below the diaphragm, from the diaphragm and from the sterno-costal wall. PHYSIOPATHOLOGY: Intrapleural chyle issue is explained by an acquired or spontaneous lesion of the thoracic duct or of one of its collaterals in the thorax. The iatrogenic or spontaneous lesions of the collaterals suggest that the latter are incontinent and have lost their valve capacity, and hence provoke a reflux of chyle from the thoracic duct. The anatomy of the chylothorax (occasionally pathological) can be specified by a pedal lymphography. FROM A THERAPEUTIC POINT OF VIEW: Treatment, essentially medical, can be completed by surgery. The medical treatment is based on re-nutrition and a diet excluding fat, supplemented by medium chain triglycerides. Surgery consists in pleural symphysis and/or suture of the damaged collaterals, or ligature of the thoracic duct. The indications depend on the severity of the chyle leakage and the type of original lesion. The indications therefore depend on the etiology and clinical evolution of each case. These different treatments, isolated or combined, lead to the regression of the effusion in nearly all cases.     

Lymphatic Drainage of the Peritoneal Space: A Pattern Dependent on Bowel Lymphatics

Background Understanding lymph drainage patterns of the peritoneum could assist in staging and treatment of gastrointestinal and ovarian malignancies. Sentinel lymph nodes (SLNs) have been identified for solid organs and the pleural space. Our purpose was to determine whether the peritoneal space has a predictable lymph node drainage pattern. Methods Rats received intraperitoneal injections of near-infrared (NIR) fluorescent tracers: namely, quantum dots (designed for retention in SLNs) or human serum albumin conjugated with IRDye800 (HSA800; designed for lymphatic flow beyond the SLN). A custom imaging system detected NIR fluorescence at 10 and 20 minutes and 1, 4, and 24 hours after injection. To determine the contribution of viscera to peritoneal lymphatic flow, additional cohorts received bowel resection before NIR tracer injection. Associations with appropriate controls were assessed with the χ² test. Results Quantum dots drained to the celiac, superior mesenteric, and periportal lymph node groups. HSA800 drained to these same groups at early time points but continued flowing to the mediastinal lymph nodes via the thoracic duct. After bowel resection, both tracers were found in the thoracic, not abdominal, lymph node groups. Additionally, HSA800 was no longer found in the thoracic duct but in the anterior chest wall and diaphragmatic lymphatics. Conclusions The peritoneal space drains to the celiac, superior mesenteric, and periportal lymph node groups first. Lymph continues via the thoracic duct to the mediastinal lymph nodes. Bowel lymphatics are a key determinant of peritoneal lymph flow, because bowel resection shifts lymph flow directly to the intrathoracic lymph nodes via chest wall lymphatics. Dr. Parungo was the recipient of an award at the SSO meeting.     

Experimental study of lymph node metastasis in thoracic esophageal carcinoma--regarding lymph node metastasis and changes in lymphatic flow by ultrafine charcoal in rabbit esophageal carcinoma model]

Esophageal carcinoma models were created by transplanting VX2 cells to rabbit esophagus endoscopically. By injecting finely divided activated charcoal into normal rabbit esophagus and tumor sites of esophageal carcinoma model, lymph flow was observed directly. Existence of lymph node metastasis was studied in detailed pathology. In 30 rabbits with upper esophageal carcinoma, lymph node metastasis was seen in 77%. Metastasis to bilateral intrathoracic paratracheal lymph node was seen in 50%, and also concentration of lymphatic flows from tumor site was seen. However, there were no metastasis and no lymph flow to abdominal lymph nodes. While, metastasis to cervical lymph nodes showed around 13%. Esophageal lymphatic flows were also seen reaching the cervical area along the esophagus. In 40 models with mid lower esophageal carcinoma, lymph node metastasis were seen in 88%. Metastasis to right and left thoracic paratracheal lymph nodes was 75% and 53%, respectively, and 25% of metastasis went to cardia lymph nodes. The lymph flows were going up and down around these lymph nodes, and reaching to lymph nodes at upper highest mediastinum or left gastric artery. The metastatic rate to the cervical lymph nodes was about 5%. There were no significant differences in lymphatic metastasis between right and left mediastinum. These findings suggest the necessity of radical dissection for both sides of the mediastinum.     

Lymphatic afferents and efferents of lymph nodes of the Barety's space. Anatomic review in adults

Lymph nodes of the Barety's space (LNLB) often involved in lung diseases are known under various names for a long time ago by pathologists. Our study involves 360 cadavers of adult subjects. The injection of a dye was performed by direct catheterization of a pulmonary segment. L.N.L.B. were directly or indirectly coloured (inter connected ganglionary network) more often from the lobes of the right lung, but from the lobes of the left lung too. From L.N.L.B. the lymphatic flow discharges in the venous confluent of the neck in the right side; in 1/4 of the cases a mediastinal efferent joints the left venous confluent too. From the lower lymph nodes of the space efferents can go to lymph nodes which are located right along the arch of the azygos vein (and then to the thoracic duct) and in the left side the group of left suprabronchial lymph nodes (then either to the thoracic duct in the mediastinum, or to the recurrent chain to the neck). At last, it seems that inside the lymph nodes themselves, lymphatic flows exist, the topography and the nature of which change according to the area interested by the injection.     

Lymphatic drainage of the heart]

The study was carried out on 91 adult cadavers to point out clearly the lymphatic drainages of the heart into the blood circulation. 45 right and 63 left ventricles and 9 right and 5 left atria were injected by means of a green modified gerota medium. A right collecting trunk received its afferents from 29 right and 5 left ventricles, ran upwards in front of the ascending aorta, involved the left brachiocephalic nodes and opened into the left subclavicular veins but also in 1 case in 5 into thoracic duct. A left collecting trunk received its afferents from 59 left and 23 right ventricles, ascended along the pulmonary trunk, involved the right paratracheal nodes and opened into the right subclavicular veins. From the right paratracheal nodes were also injected the left tracheobronchial nodes in 14 cases, and then the left brachiocephalic nodes twice, the left paratracheal nodes in 3 cases until the thoracic duct once and directly the thoracic duct in the mediastinum in one case. Afferents from the right atria ran upwards the superior vena cava and involved the right brachiocephalic nodes but connected also with the right paratracheal nodes as did the afferents of the left atria too. The connections with the thoracic duct must be emphasized.     

Immunocytochemical detection of tumour cells in the thoracic duct of patients with an adenocarcinoma of the oesophagus

BACKGROUND: Compared to other hollow viscus organs, the oesophagus has a unique anatomy in which lymphatic channels are abundantly present in the mucosa and submucosa. It has been hypothesized that tumour cells can directly disseminate from these superficial layers into the thoracic duct without passing juxta-tumoral lymph nodes. We investigated whether tumour cells of an oesophageal carcinoma could be detected in the thoracic duct during operative manipulation. METHODS: In patients with an adenocarcinoma of the oesophagus and/or gastro-oesophageal junction, undergoing a transthoracic resection with two-field lymphadenectomy, lymph was collected and cells were immunostained. RESULTS: Tumour cells could be detected in the thoracic duct lymph of only 1 out of 19 patients during operative manipulation. CONCLUSION: Peroperative data from this study do not support the hypothesis that oesophageal carcinoma readily metastasizes directly into the thoracic duct.     

Thoracic duct collaterals of lymphatic and pulmonary origin. Anatomy and chylothorax after pulmonary surgery

Dye injection of lung segments reveals the existence of lymphatic drainage of the lungs generally into cervical venous confluents and more rarely into the arch of the thoracic duct in the neck and also occasionally into the thoracic duct in the mediastinum. Direct drainage of the lymph into the thoracic duct was observed in 10 cases out of a series of 589 injections of lung segments in adult cadavers. In one half of cases, the thoracic duct was injected from the left suprabronchial lymph node chain, the origin of the left recurrent chain, and in one quarter of cases from the lateral anteroposterior right major azygos and left azygo-aortic lymph node chains, not recognised by the classical authors. More rarely, direct lymphatic collaterals drained certain segments of the lower lobes into the thoracic duct via the triangular ligament. Analysis of cases of chylothorax occurring after lung resection and observed in the authors' department or in the literature reveals that most of them can be attributed to a chyle leak from one of these pulmonary lymph collaterals. These pathways are probably also involved in the development of medical or idiopathic chylothorax.     

Superior mediastinal and neck lymphatic mapping in mid- and lower-thoracic esophageal cancer as defined by ferumoxides-enhanced magnetic resonance imaging

Objective: The purpose of this study was to detect lymphatic drainage into the superior mediastinum and neck in thoracic esophageal cancer patients using ferumoxides-enhanced magnetic resonance imaging (MRI), and to have this information assist in determining the appropriate extent of lymphadenectomy. Methods: Nine male patients with T2–T3 mid- and lower-thoracic esophageal cancer with lymph node metastasis were examined. The day before surgery, ferumoxides was endoscopically injected into the submucosal layer of the peritumoral lesion. Thereafter, lymph nodes in the superior mediastinum and neck, which were shown to be ferumoxides-enhanced on MRI, were harvested and evaluated; magnetic force from all harvested lymph nodes was measured ex vivo. Results: MRI of the superior mediastinum and neck revealed l(median) ferumoxides-enhanced lymph nodes in eight (89%) patients, and there was laterality in the lymphatic mapping in both areas. Of the 15 lymph nodes into which drainage was detected by enhanced MRI, 12 (80%) were magnetite-positive. In six patients (67%), magnetic resonance enhanced lymph nodes corresponded completely with the ex vivo magnetite examination, and in 3 patients (33%) there was partial agreement In 3 (60%) of the 5 patients that showed paratracheal and/or supraclavicular lymph node metastases, all of the affected nodes were detected by MRI; in one patient some of the affected nodes were detected. Conclusion: Ferumoxides-enhanced MRI is useful for visualizing lymphatic drainage to the superior mediastinum and neck in thoracic esophageal cancer. It is an adequate procedure to form an estimate on the appropriate extent of lymphadenectomy. Read at the Fifty-sixth Annual Meeting of the Japanese Association for Thoracic Surgery, Symposium, Tokyo, November 19–21, 2003.     

Chylous reflux in the lungs and pleurae

Lymphangiectasis of varying extent may be present in some cases of chronic pulmonary disease. Often the dilated lymphatic channels are not identified because pulmonary fibrosis and emphysema together with secondary inflammatory changes obscure the lymph vessel pathology. When chylothorax is associated with such chronic pulmonary pathology, attention may be drawn to the lymphatic system. The presence of a chylothorax is usually attributed to obstruction or injury of the thoracic duct, whereas in some cases chylous reflux into the lungs and pleurae via abnormal lymph channels in the lungs and pleurae as well as in the mediastinum may cause the chylothorax. In rare instances a patient may actually expectorate chylous fluid which seeps into the bronchi from the abnormal peribronchial lymphatics. A detailed analysis of reported cases together with some personal experience has demonstrated that pathological changes in the pulmonary and pleural lymphatic vessels are more common than is usually appreciated. The normal remarkable regenerative potential which is usually evident after experimental interruption of the lymphatics apparently is lacking in some humans due to genetic and other factors. Thus pathological changes, difficult to simulate experimentally, may be encountered. Lymphangiectasis is often found not to be limited to a single organ if complete studies of the lymphatic system are made.     

The possibility and prognostic value of secondary lymphatic cancer spread in intrapulmonic metastases of solid tumors

In the period from 1996 to 2007 operations were fulfilled in 120 patients with isolated pulmonary metastases of solid tumors (68 men and 52 women aged from 22 through 77 years): 46 patients with metastases of colorectal cancer, 28 - with cancer of the kidney, 23 - with non-small cell carcinoma of lung, 7 - with breast cancer, 9 - with endometrium cancer, 7 - with melanoma. Altogether there were 128 operations. The operations have revealed lesion of intrathoracic lymph nodes in 29 patients (24%). In most cases (21 patients) they were lesions of lymph nodes of the lung root and intrapulmonary lymph nodes. In 93% of cases (27 patients) localization of the lesion coincided with anatomical pathways of lymph outflow from the affected part of the lung. The survival rate median of the operated patients who had alterations in the lymph nodes was 21 months, in cases with intact lymphatic system it was 37 months. A conclusion is made of possible secondary lymphatic cancer spread from intrapulmonary metastases of solid tumors and its negative influence on results of treatment that allows recommendation of revision of the lymphatic system of the lungs and mediastinum in all cases of surgical treatment of intrapulmonary metastases, and in a number of cases recommendation of anatomical resections of the lung tissue as operation of choice.     

Strategies and outcomes in pulmonary and extrapulmonary metastases from renal cell cancer

Objective: Resected renal carcinoma related lung metastases (LM) are associated with higher survival rates, but surgery for extrapulmonary metastases affords good results too. Patients operated on for extrapulmonary metastases before thoracotomy are at high risk of death. The purpose of our analysis was to explore the surgical impact on the outcome of patients with such association. Methods: We reviewed the data of 15 patients operated for LM and extrapulmonary metastases from 1984 to 2005. We studied demographic and clinical characteristics, surgical results and pathological staging of the primary tumour and LM in search of prognostic factors. Results: Nephrectomy and metastasectomies were synchronous in only one patient. For the others, mean time interval between nephrectomy and surgery for LM was 74.2 months (range 19–228). Metastases were resected synchronously in two patients and metachronously in 13 of them (mean time interval: 28 months). Five-year survival of this group was 32%, median value of 18 months. The prognosis was better when the resected extrapulmonary metastases were located in the perirenal (pancreas, adrenal gland) or intrathoracic structures (lymph nodes, diaphragm) than in distant visceral organs (brain, bone, thyroid gland). The lymphatic drainage for these structures connects with the thoracic duct in a similar manner as kidneys do. Conclusion: Surgery for lung and extrapulmonary renal cell cancer-related metastases provides favourable results and is indicated when complete resection can be achieved. The role of the lymphatic system must be explored by further investigations.     

Thoracoscopic thoracic duct sealing with LigaSure in two children with refractory postoperative chylothorax

PURPOSE: Chylothorax is an uncommon complication of cardiac surgery. We report two cases of the thoracoscopic management of persistent postoperative chylothorax by thoracic duct thermofusion and section with the LigaSure device. MATERIALS AND METHODS: A 6-year-old boy and a 3-year-old girl developed persistent chylothorax following an aortic coarctation repair and a Fontan procedure, respectively. The former presented with a left chylothorax due to direct surgical injury, and the latter, a right chylothorax due to indirect lymphatic rupture secondary to increased venous pressure. In both patients, voluminous chylous drainage persisted for more than 3 weeks despite maximal medical treatment. Ultimately, a right thoracoscopic coagulation and section of the thoracic duct with the 5-mm LigaSure device was performed. The LigaSure is a computer-controlled bipolar diathermy system designed to seal blood vessels up to 7 mm in diameter, with no specific recommendations regarding the lymphatics. RESULTS: The lymph leakage ceased within 2 days in the first patient and immediately in the second one, with no recurrence after oral intake resumption on day 5. Both patients are free of recurrence at 1 year. CONCLUSION: Thoracoscopic coagulation and section of the thoracic duct above the diaphragm with the LigaSure device appears to be a simple, effective, and safe therapeutic option for treatment of refractory postoperative chylothorax in children.     

Preoperative mapping of lymphatic drainage from the tumor using ferumoxide-enhanced magnetic resonance imaging in clinical submucosal thoracic squamous cell esophageal cancer

BACKGROUND: In thoracic esophageal cancer, lymph node metastases distribute widely from the neck to the abdominal area as a result of a complex periesophageal lymphatic network. The aim of the present study was to evaluate the potential clinical utility of a new method of mapping lymphatic drainage from tumors using ferumoxide-enhanced magnetic resonance imaging (MRI). METHODS: Twenty-three patients with clinical submucosal thoracic squamous cell esophageal cancer were examined. Ferumoxides were injected endoscopically into the peritumoral submucosal layer, after which their appearance in the lymph nodes in the neck, superior mediastinum, and abdomen was evaluated using MRI. RESULTS: Flux of ferumoxides from tumors was detected in all 23 patients. Among the 20 patients with middle and lower thoracic esophageal cancers, there was no lymphatic drainage to the neck in 5 (25%) patients, none to the neck and superior mediastinum in 4 (20%), and none to the abdomen in 2 (10%), which could enable the extent of lymph node dissection to be reduced. We diagnosed clinical negative lymph node metastasis (N0) in 17 patients; the remaining 6 patients were diagnosed with clinical lymph node metastasis. Two patients (12%) diagnosed clinical N0, showed pathologic lymph node metastasis. Ferumoxide-enhanced MRI detected an influx of contrast agent into the metastatic node in both patients. CONCLUSIONS: Ferumoxide-enhanced MRI lymphatic mapping enables detection of the direction and area of lymphatic flux. It thus has the potential to improve our ability to gauge the appropriate extent of treatment in clinical submucosal squamous cell esophageal cancer.     

Chylothorax complicating pulmonary resection

Background. Chylothorax complicating pulmonary resection (CCPR) is infrequent and surgical treatment is for the most part avoided. The purpose of this study is to analyze the clinical and therapeutic characteristics of this complication.

Methods. From March 1981 to June 2001, 26 cases of CCPR (24 men and 2 women; mean age 57 years) were treated in two departments of thoracic surgery. Twenty-five cases complicated lung resection for lung cancer (lobectomy n = 14, bilobectomy n = 3, pneumonectomy n = 8) and 1 case followed lobectomy for a benign lesion. Medical history, location, and characteristics of the chylothorax, lymphography, and clinical evolution after medical or surgical therapy were studied.

Results. Medical history was never predictive of CCPR. Chylothorax was right sided in 18 cases and left sided in 8 cases. The total amount of chyle ranged from 1.9 L to 27.9 L per patient with a mean of 7.9 L (pneumonectomy 12.3 L and lobectomy 6.3 L). In 15 patients (pneumonectomy n = 2 and lobectomy n = 13) mean quantity of daily chyle was 0.3 L. All these patients recovered with conservative therapy except for 2 patients who underwent drainage and talc slurry (n = 1) and video-assisted lysis of adhesions (n = 1). In the remaining 11 patients (pneumonectomy n = 6 and lobectomy n = 5) mean quantity of daily chyle was 1 L. The chylous leak was seen at lymphography (n = 4), during reoperation (n = 2), or at lymphography and reoperation (n = 3). The location was clearly identified at the level of thoracic duct tributaries in all cases. In 4 postlobectomy cases (4 of 7), surgery was not performed because of the therapeutic usefulness of lymphography. Reoperation was necessary in 6 cases (postpneumonectomy n = 5, postlobectomy n = 1) and consisted of duct ligation (n = 2), leak suture (n = 3), and fibrin glue (n = 1).

Conclusions. CCPR is rare and appears to respond well to medical treatment owing to the fact that the thoracic duct is generally patent as the leak is due to injury of its tributaries. When surgery is considered, lymphography may help to select cases in which conservative medical therapy should be continued. However, in a small number of cases, usually after pneumonectomy, surgery remains mandatory.     

Lymphatic removal of dialysate from the peritoneal cavity of anesthetized sheep

Several investigators have suggested that the lymphatic circulation reduces ultrafiltration in continuous ambulatory peritoneal dialysis (CAPD). The purpose of this study was to assess lymphatic drainage of the peritoneal cavity directly in anesthetized sheep under dialysis conditions. Lymph was collected from the caudal mediastinal lymph node and the thoracic duct, both of which are involved in the lymphatic drainage of the ovine peritoneal cavity, and from the prescapular lymph node, which is not involved in peritoneal lymphatic drainage. Fifty ml/kg volumes of a mildly hypertonic dialysis solution (Dianeal 1.5%) containing 25 microCi 125I-human serum albumin were instilled into the peritoneal cavity, and lymph flows and the appearance of labeled protein in the lymphatic and vascular compartments were monitored for six hours. Following the instillation of dialysis fluid there was a tendency for lymph flow rates from the thoracic duct to increase but these changes were not significant. However, flow rates from the caudal lymphatic demonstrated significant increases, especially in the final three hours of the monitoring period. Only about 8% of the radiolabeled albumin was removed from the peritoneal cavity over six hours (that is, 92% was left in the peritoneal space). Of the albumin removed, approximately 17% of this was drained by abdominal visceral lymphatics into the thoracic duct. About 25% passed through the diaphragm into the caudal mediastinal lymph node and into efferent lymph. Since the efferent lymphatic duct of the caudal mediastinal node empties directly into the thoracic duct, about 42% of all protein removed from the peritoneal cavity of the sheep was ultimately transported to the thoracic duct.(ABSTRACT TRUNCATED AT 250 WORDS)     

Post-esophagectomy chylous leakage from a duplicated left-sided thoracic duct ligated successfully with left-sided video-assisted thoracoscopic surgery

Three months after esophagectomy for esophageal cancer, a 58-year-old man presented with fluid trapped in his upper mediastinum due to chylous leakage from a duplicated left-sided thoracic duct that remained after excision of the main thoracic duct. Classical lymphangiography using lipiodol confirmed the presence of duplicated thoracic ducts. Conservative treatments were not effective, and then we performed ligation of the left-sided thoracic duct with left-sided video-assisted thoracoscopic surgery. Anatomic variations of the thoracic duct can result in chylous leakage after thoracic surgery. Even if the patient has anomaly of the thoracic duct, classical lymphangiography is useful for detecting locations of the thoracic duct precisely, allowing for certain ligation of the duct with video-assisted thoracoscopic surgery.     

Unique distribution patterns of metastatic lymph nodes in patients with superficial carcinoma of the thoracic oesophagus.

BACKGROUND: Lymph node metastasis is commonly found in carcinoma of the thoracic oesophagus, even when the tumour invades only the submucosa. Although lymph node status greatly influences the outcome, the pattern of early lymphatic spread has not been investigated, and the role of lymph node dissection is still a matter of controversy. METHODS: A series of 110 patients with superficial carcinoma who underwent systematic extended lymph node dissection was investigated retrospectively. RESULTS: Lymph node involvement was found in 0 per cent (none of nine), 23 per cent (five of 22) and 49 per cent (38 of 78) of tumours that invaded the lamina propria, muscularis mucosa and submucosa respectively. Anatomically distant lymph nodes (recurrent nerve nodes and perigastric nodes) were involved more frequently than other intrathoracic nodes adjacent to the main tumour. Only three patients had involvement limited to the intrathoracic group, and in carcinoma that invaded only the muscularis mucosae, all metastatic nodes were located at the thoracocervical junction or in the abdomen. The 5-year survival rate was 89 per cent in the node-negative group and 54 per cent in the node-positive group (P < 0.0003). CONCLUSION: The recurrent nerve nodes and perigastric nodes are the principal proximal regional lymph nodes involved in superficial carcinoma of the thoracic oesophagus. Systematic lymph node dissection, which included these nodes, yielded an acceptable and favourable outcome in patients with node-positive superficial carcinoma.