RESUMO
A coronary artery aneurysm is an uncommon vascular disorder, and it can be a life-threatening disease when associated with rupture or an embolism. A 52-year-old man was found to have a 50-mm coronary artery aneurysm at the right coronary artery, and the aneurysm was completely occluded by a thrombus. He had no symptoms after arriving at our hospital, and his hemodynamics was stable. Therefore, initially, we administered anticoagulation therapy involving heparin. After therapy, the distal coronary artery was detected when the thrombus dissolved, and elective surgery was planned. Coronary artery bypass grafting, ligation of the inflow and outflow vessels, and resection of the aneurysm were performed. Early anticoagulation therapy and surgical aneurysm resection were effective for treating the completely occluded coronary artery aneurysm. We herein report this rare case of a giant coronary artery aneurysm occluded completely by a thrombus and treated successfully by anticoagulation therapy and surgical aneurysm resection.
RESUMO
Congenital left atrial wall aneurysm is a rare disorder that occurs in a wide range of age groups from infancy to adulthood. Here, we present a case of a congenital left atrial wall aneurysm that was detected in a 19-year-old man who was surgically treated. Although the patient was asymptomatic without any pre-existing conditions, chest radiography performed as part of a routine health examination detected abnormalities in the heart. Contrast-enhanced computed tomography revealed a giant aneurysm measuring 72â¯mmâ¯×â¯56â¯mm that extended from the posteroinferior wall of the left atrium to the posterior surface of the left ventricle. Transthoracic echocardiography revealed mild mitral regurgitation. The patient was diagnosed as having a congenital left atrial wall aneurysm associated with mild mitral regurgitation. The aneurysm was resected through median sternotomy under cardiopulmonary bypass with cardioplegic arrest. During surgery, no structural abnormalities were noted in the mitral valve. After surgery, the patient was discharged without complications. Neither recurrence of the aneurysm nor exacerbation of mitral regurgitation was observed at 1â¯year postoperatively. Learning objective: A congenital left atrial wall aneurysm is a rare disorder. Rupture of the aneurysm is rare. However, when they are left untreated, there are concerns regarding arrhythmias, heart failure, and systemic embolism. Thus, surgical treatment is recommended. Aneurysms are resected under cardiopulmonary bypass. In cases of aneurysms complicated by moderate or severer mitral regurgitation, mitral valve repair is necessary. The prognosis following surgical treatment is favorable.
RESUMO
We report a 63-year-old woman came to our hospital with exertional dyspnea, palpitations, and abdominal distention. Echocardiography showed mitral, aortic, and tricuspid valve insufficiency, for which surgery was indicated. Twenty-six years ago, during dental therapy, she was diagnosed with metal allergy. A patch test demonstrated allergic reactions to manganese, chromium, and zinc. The patient underwent mitral and aortic valve replacement with the On-X prosthetic heart valve, which is primarily made of titanium and devoid of the allergens. She also underwent tricuspid valve repair with a Contour 3D annuloplasty ring, which is made of titanium alloy. She manifested no allergic symptoms three years after surgery. This case elucidates the importance of history taking regarding metal allergy and identification of allergens by patch testing in patients undergoing cardiac surgery involving metal device implantation.
Assuntos
Anuloplastia da Valva Cardíaca , Implante de Prótese de Valva Cardíaca , Próteses Valvulares Cardíacas , Hipersensibilidade , Anuloplastia da Valva Mitral , Insuficiência da Valva Mitral , Insuficiência da Valva Tricúspide , Valva Aórtica/diagnóstico por imagem , Valva Aórtica/cirurgia , Feminino , Próteses Valvulares Cardíacas/efeitos adversos , Humanos , Hipersensibilidade/etiologia , Pessoa de Meia-Idade , Insuficiência da Valva Mitral/cirurgia , Valva Tricúspide/diagnóstico por imagem , Valva Tricúspide/cirurgia , Insuficiência da Valva Tricúspide/diagnóstico por imagem , Insuficiência da Valva Tricúspide/etiologia , Insuficiência da Valva Tricúspide/cirurgiaAssuntos
Insuficiência da Valva Mitral , Veias Pulmonares , Cardiomegalia , Criança , Átrios do Coração/diagnóstico por imagem , Átrios do Coração/cirurgia , Humanos , Valva Mitral/diagnóstico por imagem , Valva Mitral/cirurgia , Insuficiência da Valva Mitral/diagnóstico por imagem , Insuficiência da Valva Mitral/etiologia , Insuficiência da Valva Mitral/cirurgia , Veias Pulmonares/diagnóstico por imagem , Veias Pulmonares/cirurgiaRESUMO
We report the long-term clinical outcome of an 8-month-old infant who underwent tricuspid reconstruction using fresh autologous pericardium for severe tricuspid regurgitation due to defects in the leaflets of the tricuspid valve after ventricular septal defect closure and ablation. Ten years after surgery, the tricuspid function is good with mild regurgitation and mild stenosis. From the age of 8 months to 11 years, the patient's body weight and height increased fourfold and twofold, respectively. Thus, a fresh autologous pericardial patch could be the material of choice for tricuspid leaflet repair in pediatric patients.
Assuntos
Comunicação Interventricular , Insuficiência da Valva Tricúspide , Humanos , Lactente , Pericárdio/transplante , Valva Tricúspide/diagnóstico por imagem , Valva Tricúspide/cirurgia , Insuficiência da Valva Tricúspide/diagnóstico por imagem , Insuficiência da Valva Tricúspide/cirurgiaRESUMO
A 7-year-old boy with a history of neonatal pulmonary artery banding underwent almost complete closure of a sieve-like "Swiss-cheese" ventricular septal defect, using a combination sandwich patch technique through a right ventriculotomy. Although defects existed in the high-, mid-, and low-trabecular septa, a right ventriculotomy and division of the muscle trabeculations continuing the septal and moderator bands helped delineate the edges of the defects. Although patients with "Swiss-cheese" ventricular septal defects may be candidates for a Fontan operation conventionally, a combination patch technique could be considered the procedure of choice.
Assuntos
Procedimentos Cirúrgicos Cardíacos , Comunicação Interventricular , Septo Interventricular , Criança , Comunicação Interventricular/diagnóstico por imagem , Comunicação Interventricular/cirurgia , Ventrículos do Coração , Humanos , Recém-Nascido , MasculinoRESUMO
Total cavopulmonary connection (TCPC) conversion prevents late complications after the atrio-pulmonary-Fontan procedure. However, the outcomes and effects of TCPC conversion are not fully known. We performed TCPC conversion in 31 patients (2004~2017). Concomitantly, we performed anti-arrhythmia surgery in 28 patients( 90%), atrioventricular valve surgery in 4, and pacemaker implantation in 2. There were no perioperative deaths, but one late death occurred due to protein-losing gastroenteropathy. Five-year survival was 96.8%. Eleven patients were readmitted for various reasons, including arrhythmia in 7 and heart failure in 1. The 5-year cardiac event-free rate was 67.7%. The cardiac index was significantly improved:1.58 l/min/m2 before to 3.57 l/min/m2 after surgery ( p=0.0075). Surgical and midterm outcomes of TCPC conversion were favorable. In the perioperative and late periods, therapeutic intervention was usually for atrial arrhythmia. This study demonstrated that TCPC conversion is an effective therapeutic procedure.
Assuntos
Técnica de Fontan , Cardiopatias Congênitas , Antiarrítmicos , Arritmias Cardíacas , Cardiopatias Congênitas/cirurgia , Humanos , Artéria PulmonarRESUMO
Mid-aortic syndrome (MAS) is a very rare disease characterized by stenosis from the distal of the thoracic aorta to the abdominal aorta, in many case it is found as a result of hypertension and the like, and it needs surgical intervention in early childhood to adolescence. Here, we report a case of MAS which recognized prominent left ventricular myocardial hypertrophy from the early stage and needed surgical intervention in the infancy. We selected patch angioplasty using expanded polytetrafluoro ethylene( ePTFE) graft, and after surgery pressure gradient was disappeared.
Assuntos
Hipertrofia Ventricular Esquerda/cirurgia , Aorta Abdominal , Aorta Torácica , Constrição Patológica/etiologia , Humanos , Hipertensão/complicações , Hipertrofia Ventricular Esquerda/fisiopatologia , Lactente , SíndromeRESUMO
A 14-year-old boy presented to our institution with a diagnosis of acute type A dissection. He was diagnosed with Loeys-Dietz syndrome and underwent aortic valve sparing repair at the age of 9 years. Emergency total arch repair with elephant trunk (ET) was performed successfully; echocardiogram before discharge showed normal left ventricular function and size. However, he was readmitted 1 month after discharge with significant left ventricular dysfunction and dilatation. The small folded ET caused a pressure gradient between the upper and lower body, which might deteriorate left ventricular function. Urgent balloon arterioplasty was performed to unfold the ET graft, resulting in no improvement of left ventricular function. ET removal and descending aorta replacement with an 18-mm graft was performed eventually. Left ventricular function and brain natriuretic peptide gradually improved after approximately 2 years of follow-up.
Assuntos
Implante de Prótese Vascular/efeitos adversos , Cardiomiopatia Dilatada/etiologia , Síndrome de Loeys-Dietz/cirurgia , Doença Aguda , Adolescente , Implante de Prótese Vascular/métodos , Humanos , Síndrome de Loeys-Dietz/diagnóstico por imagem , Masculino , Reoperação/métodos , Tomografia Computadorizada por Raios XRESUMO
OBJECTIVES: Bilateral pulmonary artery banding (bil-PAB) has been developed as a part of a hybrid procedure for hypoplastic left heart syndrome (HLHS). We use this procedure for palliation of complex congenital heart disease, particularly in patients with arch anomaly. We reviewed our experience with bil-PAB. METHODS: Sixty-six consecutive cases between 2003 and 2014 were reviewed retrospectively. RESULTS: Fifty-one patients (77%) had single ventricle physiology (HLHS: 37, HLHS variant: 13, others: 1). Twelve patients had biventricular physiology [5 interrupted aortic arch with ventricular septal defect (VSD); 4 coarctation of the aorta with VSD; 2 truncus arteriosus; 1 other]. In 3 patients, it was difficult to determine if the physiology was single ventricle or biventricle due to borderline left ventricle size. Age and body weight at the time of operation were 4.3 ± 3.4 days and 2.7 ± 0.5 kg, respectively. Overall hospital mortality was 11% (7/66). Of the 42 patients from 2010, only 1 with multiple anomalies died between bil-PAB and the second-stage operation. Thirteen patients (20%) required reoperation of bil-PAB. The mean waiting time for the next operation was 44.3 ± 42.8 days. The body weight at the second-stage operation was 3.2 ± 0.8 kg. Seven (11%) patients developed patent ductus arteriosus obstruction during the waiting period. Twenty-four patients were 2.5 kg or less; 20 patients in this group progressed to the second-stage operation and of these 19 gained body weight. Forty-two patients were above 2.5 kg, but of these only 23 patients gained body weight. Ten patients underwent bil-PAB because of shock and 8 of these recovered from shock. In 2 borderline cases, the patients underwent the Norwood procedure and 1 patient had arch repair and VSD closure. CONCLUSIONS: Bil-PAB could be applied to a wide variety of complex diseases. Our mortality rates with bil-PAB improved significantly post-2010. Good indications for bil-PAB were shock and situations where it was unclear whether the physiology was single ventricle or biventricular. Body weight gain was difficult to predict, but patients weighing less than 2.5 kg could be expected to gain body weight after the procedure.
Assuntos
Síndrome do Coração Esquerdo Hipoplásico/cirurgia , Artéria Pulmonar/cirurgia , Humanos , Recém-Nascido , Procedimentos de Norwood/métodos , Reoperação , Resultado do Tratamento , Tronco Arterial/cirurgia , Aumento de PesoRESUMO
We herein report a case of a hypoplastic left heart syndrome variant complicated with partial anomalous pulmonary venous connection to the left innominate vein. We left the vertical vein at the time of the bidirectional Glenn procedure, and ligated the vertical vein at the time of the total cavopulmonary connection procedure, without reconnecting the vertical vein to the left atrium. Because of the development of an interlobar vein draining from the left upper lung into the lower lung after the bidirectional Glenn procedure, the circulation of the left upper lung was preserved after the total cavopulmonary connection procedure.
Assuntos
Anormalidades Múltiplas , Veias Braquiocefálicas/cirurgia , Técnica de Fontan , Síndrome do Coração Esquerdo Hipoplásico/cirurgia , Veias Pulmonares/cirurgia , Veias Braquiocefálicas/anormalidades , Veias Braquiocefálicas/diagnóstico por imagem , Veias Braquiocefálicas/fisiopatologia , Pré-Escolar , Feminino , Humanos , Síndrome do Coração Esquerdo Hipoplásico/diagnóstico por imagem , Síndrome do Coração Esquerdo Hipoplásico/fisiopatologia , Ligadura , Flebografia , Circulação Pulmonar , Veias Pulmonares/anormalidades , Veias Pulmonares/diagnóstico por imagem , Veias Pulmonares/fisiopatologia , Resultado do TratamentoRESUMO
Congenital occlusion of the left main coronary trunk is a life-threatening abnormality, and its optimal management remains controversial. This report describes a case of successful patch angioplasty with auto-pulmonary artery for a 12-year-old boy with congenital left main trunk occlusion. We divided the main pulmonary artery, harvested a pulmonary artery wall strip, and performed patch angioplasty of the occluded left main trunk ostium. We were able to clearly expose the left main trunk behind the pulmonary artery because the obstruction was divided for the patch material. The postoperative course was uneventful, and coronary angiography at 4 months after surgery showed excellent patency of the left main trunk. The auto-pulmonary arterial wall was easy to handle during angioplasty, and its favorable durability has been established both in the Ross procedures and in an arterial switch procedure. Therefore, we conclude that patch angioplasty using a piece of the pulmonary arterial wall represents a good alternative to conventional coronary artery bypass grafting.
Assuntos
Angioplastia/métodos , Oclusão Coronária/cirurgia , Anomalias dos Vasos Coronários/cirurgia , Artéria Pulmonar/transplante , Criança , Angiografia Coronária , Oclusão Coronária/congênito , Vasos Coronários/cirurgia , Humanos , MasculinoRESUMO
Aortico-left ventricular tunnel (ALVT) is a rare congenital anomaly presenting abnormal connection between the ascending aorta and the left ventricle. In most reported cases, the aortic end of the tunnel is above the right coronary sinus. Cases of ALVT related to the left aortic sinus are extremely rare. We herein report a case diagnosed preoperatively as ALVT arising from the left aortic sinus. The actual diagnosis observed at surgery was aortic valve insufficiency with a left ventricular outflow tract aneurysm. We successfully performed aortic valve repair and plication of the left ventricular aneurysm.
Assuntos
Insuficiência da Valva Aórtica/cirurgia , Erros de Diagnóstico , Aneurisma Cardíaco/diagnóstico , Cardiopatias Congênitas/diagnóstico , Aorta/diagnóstico por imagem , Insuficiência da Valva Aórtica/diagnóstico , Insuficiência da Valva Aórtica/diagnóstico por imagem , Ecocardiografia Transesofagiana , Aneurisma Cardíaco/diagnóstico por imagem , Aneurisma Cardíaco/cirurgia , Cardiopatias Congênitas/diagnóstico por imagem , Ventrículos do Coração/diagnóstico por imagem , Humanos , Lactente , MasculinoRESUMO
BACKGROUND: Atrial tachyarrhythmias are frequent complications in the late period after the Fontan procedure, and important risk factors for a poor prognosis. The impact of Fontan conversion and arrhythmia surgery in failed Fontan patients has been described in many reports. OBJECTIVE: We evaluated our experience with Fontan conversion procedures, concomitant arrhythmia surgery, and pacemaker implantation. METHODS: We reviewed the hospital records of 25 consecutive patients who underwent a Fontan conversion procedure from January 2004 to March 2012. Twenty-four patients had arrhythmia surgery using cryoablation and radiofrequency ablation at the time of conversion. A bilateral atrial maze procedure was performed in 6 patients, right-side maze in 15, and isthmus block in 3. Three patients with a diagnosis of corrected transposition of the great arteries underwent simultaneous pacemaker implantation electively. RESULTS: There was no early death and one late death during a mean follow-up period of 21.2 months. Three tachyarrhythmia recurrences developed, and there were 4 occurrences of sinus bradycardia. Five of these patients required postoperative pacemaker implantation. CONCLUSION: The mid-term results of Fontan conversion and arrhythmia surgery in our institute were satisfactory. The occurrence of unexpected postoperative pacemaker requirement was high in the patients who underwent a right atrial or bilateral atrial maze procedure. Pacemaker or lead implantation is recommended for patients planned to undergo a right-side or full maze procedure.
Assuntos
Fibrilação Atrial/cirurgia , Estimulação Cardíaca Artificial , Ablação por Cateter , Criocirurgia , Técnica de Fontan/efeitos adversos , Marca-Passo Artificial , Taquicardia Supraventricular/cirurgia , Adolescente , Adulto , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/etiologia , Ablação por Cateter/efeitos adversos , Criança , Criocirurgia/efeitos adversos , Feminino , Humanos , Masculino , Recidiva , Reoperação , Fatores de Risco , Taquicardia Supraventricular/diagnóstico , Taquicardia Supraventricular/etiologia , Fatores de Tempo , Resultado do Tratamento , Adulto JovemRESUMO
A 60-year-old woman was referred to the Department of Cardiovascular Surgery of Social Insurance Chukyo Hospital for the rupture of a postinfarction papillary muscle. The rupture was in the posterior part of the anterolateral papillary muscle, in which more than two-thirds of its posterior leaflet was prolapsed. Mortality from the surgical repair of a papillary muscle rupture is quite high. For this case, we resuspended the uninfarcted papillary muscle heads case to preserve mitral ventricular continuity because the mitral annulus was quite small and more than two-thirds of the posterior leaflet were detached from the papillary muscle. The post-operative course of the patient was uneventful. Resuspension of uninfarcted papillary muscle is a useful technique to repair a rupture in the papillary muscle.
Assuntos
Ruptura Cardíaca Pós-Infarto/cirurgia , Implante de Prótese de Valva Cardíaca , Insuficiência da Valva Mitral/cirurgia , Valva Mitral/cirurgia , Músculos Papilares/cirurgia , Angiografia Coronária , Ecocardiografia Transesofagiana , Feminino , Ruptura Cardíaca Pós-Infarto/complicações , Ruptura Cardíaca Pós-Infarto/diagnóstico , Humanos , Pessoa de Meia-Idade , Valva Mitral/diagnóstico por imagem , Insuficiência da Valva Mitral/diagnóstico , Insuficiência da Valva Mitral/etiologia , Músculos Papilares/diagnóstico por imagem , Músculos Papilares/lesões , Resultado do TratamentoRESUMO
A 79-year-old woman was referred to undergo surgery for a type A dissection. The patient had a history of previous coronary artery bypass. She was in shock and had a hematoma surrounding the ascending aorta and the heart. In this case, a coronary sinus cardioplegia cannula was placed under a short period of circulatory arrest via a small atriotomy, and the atriotomy was closed immediately to establish selective cerebral perfusion.
Assuntos
Dissecção Aórtica/cirurgia , Ruptura Aórtica/cirurgia , Implante de Prótese Vascular , Ponte de Artéria Coronária , Seio Coronário/fisiopatologia , Parada Cardíaca Induzida/métodos , Idoso , Dissecção Aórtica/complicações , Dissecção Aórtica/diagnóstico por imagem , Dissecção Aórtica/fisiopatologia , Ruptura Aórtica/diagnóstico por imagem , Ruptura Aórtica/etiologia , Ruptura Aórtica/fisiopatologia , Aortografia/métodos , Ponte Cardiopulmonar , Catéteres , Circulação Cerebrovascular , Feminino , Parada Cardíaca Induzida/instrumentação , Hematoma/etiologia , Hematoma/cirurgia , Humanos , Veia Safena/transplante , Esternotomia , Fatores de Tempo , Tomografia Computadorizada por Raios X , Resultado do TratamentoRESUMO
We present a case of severe hemolysis following a mitral valve repair, which was successfully treated by removing the annuloplasty ring. The etiology of the hemolysis appeared to be a small regurgitant jet at the level of the annuloplasty ring.
Assuntos
Implante de Prótese de Valva Cardíaca , Próteses Valvulares Cardíacas/efeitos adversos , Hemólise , Anuloplastia da Valva Mitral , Valva Mitral/cirurgia , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/cirurgia , Falha de Prótese/etiologia , Idoso , Feminino , Humanos , Resultado do TratamentoRESUMO
We examined the effectiveness of combination therapy for biventricular pacing after cardiac surgery. We performed biventricular pacing in seven patients until April 2003. The diagnosis of the patients was ischemic cardiomyopathy (ICM) in four patients and dilated cardiomyopathy (DCM) in three patients. The implantation method of biventricular pacing was performed with a myocardial electrode through a median sternotomy. DDD-R and SSI-R were used to perform biventricular pacing. A Y-adapter was connected to a generator so that the 2 leads could be implanted in both the right ventricles (RV) and left ventricles (LV). The clinical symptoms were New York Heart Association (NYHA) classification of 3.7+/-0.3 preoperatively and 1.8+/-0.6 postoperatively, showing a significant improvement (p<0.001). The cardiac index (CI) was 1.9+/-0.2 L/min/m2 preoperatively and 3.0+/-0.6 L/min/m2 postoperatively (p<0.05). The pulmonary capillary wedge pressure (PCWP) was 19.5+/-2.6 mmHg preoperatively and 13.6+/-2.0 mmHg postoperatively, showing a significant improvement (p<0.05). The intracardiac potential and threshold values were: left atrium 1.9+/-1.0 mV, threshold value (PW: 0.45 msec) 2.1+/-0.6 V, LV 4.9+/-4.23 mV, threshold value (PW: 0.45 msec) 2.2+/-1.51 V, and RV 3.6+/-0.9 V, threshold value (PW: 0.45 msec) 2.0+/-0.7 V. The LV and RV threshold values were high. The QRS interval improved from 158.4+/-18.0 msec preoperatively to 110+/-13.4 msec postoperatively, showing a significant reduction. This combination therapy when compared to the use of the biventricular pacing method used at the current time, does have the risks of cardiac surgery, but the clinical symptoms and hemodynamic performance improvement are great.
Assuntos
Estimulação Cardíaca Artificial/métodos , Cardiomiopatias/terapia , Cardiomiopatia Dilatada/terapia , Insuficiência Cardíaca/terapia , Isquemia Miocárdica/terapia , Adulto , Idoso , Cardiomiopatias/cirurgia , Cardiomiopatia Dilatada/cirurgia , Eletrocardiografia , Eletrodos Implantados , Feminino , Insuficiência Cardíaca/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Isquemia Miocárdica/cirurgiaRESUMO
Between January 1993 and December 2001, we employed percutaneous cardiopulmonary support (PCPS) in 35 patients. PCPS was used for postcardiotomy in 25 of these patients who could not be weaned from cardiopulmonary bypass (CPB) because of severe cardiogenic shock. In the other 10 patients, PCPS was used for a non-surgical disease. Twenty-nine patients (82.9%) were weaned from PCPS, and 28 (80.0%) survived. The other 7 patients (20.0%) died due to postoperative complications. The causes of death were multiple organ failure (MOF) due to wound bleeding, low cardiac output syndrome (LOS), myonephropathic metabolic syndrome (MNMS) with severe lower limbs ischemia, cerebrovascular accident (CVA), and sepsis. The first cause for the complications was postoperative sustained severe heart failure. To improve the survival rate, it was necessary to prevent bleeding and begin PCPS at an earlier stage.
Assuntos
Baixo Débito Cardíaco/terapia , Ponte Cardiopulmonar , Choque Cardiogênico/terapia , Adulto , Idoso , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Ponte Cardiopulmonar/efeitos adversos , Ponte Cardiopulmonar/instrumentação , Ponte Cardiopulmonar/métodos , Feminino , Humanos , Balão Intra-Aórtico , Masculino , Pessoa de Meia-Idade , Oxigenadores de Membrana , Estudos RetrospectivosRESUMO
We report a case of a 70-year-old male smoker with a single primary tumor 2.5 x 3.0 cm in size in the right lung lower lobe. A transbronchial lung biopsy revealed squamous cell carcinoma of the lung. We performed right lower lobectomy with lymph node dissection (ND2a). The resected specimen consisted of three different cell types; small cell carcinoma, adenocarcinoma and squamous cell carcinoma (in a ratio of 70: 20: 10). Each cancer cell types had metastasized to different lymph nodes. The final diagnosis was a combined small cell carcinoma in the lung. Combined small cell carcinoma is uncommon, but is nevertheless a well-described diagnostic category in lung cancers.