[Descending Thoracic Aortic Injury in Flail Chest]. / Poranení sestupné hrudní aorty pri blokové zlomenine zeber.

The authors present a case of 74-year-old female patient who suffered a flail chest in motor vehicle accident. First day after injury a descending thoracic aorta was injured, most likely during manipulation with the patient. This injury was verified by operation, which was indicated 26 hours after the hospital admission, because of a sudden decrease of blood pressure with blood loss over 600 ml through the chest tube. The female patient died during surgery despite all efforts. Due to our experience with this rare case and after literature studying, we would recommend to consider early surgical revision. Based on the close contact of severely displaced sharp edges of ribs to the descending aorta, which was visible on the CT scan. Even through the absence of clear leak of contrast in the CT examination. We could resect these parts of ribs. Key words: flail chest, descending thoracic aortic injury.

[Surgical Treatment of Clavicle Midshaft Fractures - Prospective Randomized Trial]. / Operacní lécba zlomeniny diafýzy klícní kosti ­ prospektivní randomizovaná studie.

PURPOSE OF THE STUDY Comparison of the outcomes of clavicle midshaft fractures using two different surgical techniques, namely intramedullar osteosynthesis using elastic stable intramedullary nailing (ESIN) with medial cap and extramedullar plate osteosynthesis. MATERIAL AND METHODS The prospective randomized trial was conducted at the Department of Trauma Surgery of the Department of Surgery of the University Hospital Hradec Králové in the Czech Republic at the Level I Trauma Center between 2014 and 2018 and compared two types of osteosynthesis of clavicle midshaft fractures. 60 patients were enrolled in the study and were randomly assigned to one of the two groups. In Group 1, the participants were treated by ESIN and in Group 2 by plate osteosynthesis. The operative technique was chosen by the sealed envelope method. According to the randomization list created by a specialised statistical company, every envelope was marked with a unique number and contained the intramedullar "IM", or the extramedullar "EM" sign. RESULTS The observation of statistical parameters by unpaired t test detected significantly different results: a shorter incision using ESIN osteosynthesis (median = 2.9 cm) compared with plate osteosynthesis (median 14 cm, p < 0.001), longer X-ray exposure using ESIN (median = 325 s) compared with plate osteosynthesis (median = 16.5 s, p < 0.001) and radiation dose using ESIN (median = 996 cGy/cm2) compared with plate osteosynthesis (median = 4 cGy/cm2, p < 0.001). The difference in other parameters such as operative time, in-patient length of stay and duration of rehabilitation was not statistically significant. The time to clavicle fracture repair was comparable in both the surgical arms, i.e. approximately 3 months. Also, the duration of incapacity for work was not statistically different. Functional Constant Shoulder Score at a one-year followup is comparable in both the two arms (p = 0.268). The Dunn s method necessitated a longer operative time when treating multifragmental midshaft clavicle fracture by the ESIN compared to simple fractures. No statistically significant difference was detected in the operative time of different procedures and in the number of bone fragments. The functional outcome was excellent in 25 patients (83%) in each method. DISCUSSION Most midshaft clavicle fractures are still treated non-operatively with good outcomes. The indication for surgical treatment is the dislocation of fragments greater than the width of the clavicle bone, the shortening of fragments greater than 2 cm and the angulation of more than 30°. Patient after operative treatment profits from bone healing by absolute or relative stability. In recent years, new intramedullar techniques other than open plate reduction and fixation have emerged. For example, elastic stable intramedullary titan nailing. Both the methods are full-fledged without functional differences in longterm follow-up. CONCLUSIONS We consider the intramedullar osteosynthesis to be the most appropriate surgical approach for simple midshaft spiral, oblique and transverse clavicle fractures and also wedge oblique fractures. Plate osteosynthesis is useful for all types of fractures. No statistically significant difference in the rate of bone healing was observed after intramedullar or extramedullar ostesynthesis, but multifragmentary fractures healed faster when plate osteosynthesis was used. The determining factor for the received radiation dose is solely the surgical method, not the type of fracture. There is a statistically significant difference in shorter X-ray exposure and lower received radiation dose in plate fixation and reduction. The complication rate is comparable in both the methods. Key words: elastic stable intramedullary nailing, midshaft clavicle fracture, ESIN, TEN, titan elastic nail, clavicle plate osteosynthesis, 3.5 LCP clavicular plate, indication for midshaft fracture treatment.

[Role of Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) to Save Life in Bleeding in a Patient with a Pelvic Ring Injury]. / Role balonové endovaskulární okluze aorty (REBOA) pri záchrane zivota u pacientu s krvácením z pánve.

The author presents a case study of the use of resuscitative endovascular balloon occlusion (REBOA) as a suitable alternative to thoracotomy and clamping of the descending aorta to control retroperitoneal bleeding in a patient with a pelvic injury. The patient who suffered multiple trauma after car accident, type C pelvic injury and retroperitoneal bleeding among other things, was following the pre-hospital ambulance care transported to the department of emergency medicine, with catecholamine infusion to support the blood flow. After the primary survey following the ATLS principles, the patient was taken for a CT scan. The CT examination revealed also multiple sources of retroperitoneal bleeding. Subsequently, the patient was brought to the operating room, where endovascular balloon occlusion of the descending aorta was performed to temporarily control retroperitoneal bleeding, which provided more time to treat the patient in line with the damage control surgery principles. In bleeding patients who suffered blunt torso traumas and serious haemorrhagic shock, or patients "in extremis", the survival after emergency thoracotomy ranges only around 1%. The to date results of REBOA technique applied in same indications are very promising globally. The survival rate increases multiple times especially in hypotensive patients, without the necessity of their immediate cardiopulmonary resuscitation. Key words:resuscitative balloon occlusion of the aorta, REBOA, haemorrhagic shock, retroperitoneal bleeding.

Disparity between two-dimensional echocardiographic and electroanatomic left and right atrial volumes in patients undergoing catheter ablation for long-standing persistent atrial fibrillation.

Left atrial (LA) volume (LAV) is used for the selection of patients with atrial fibrillation (AF) to rhythm control strategies. Calculation of LAV from the LA diameters and areas by two-dimensional (2D) echocardiography may result in significant error. Accuracy of atrial volume assessment has never been studied in patients with long-standing persistent AF (LSPAF) and significant atrial remodeling. This study investigated correlation and agreement between 2D echocardiographic (Simpson method) and electroanatomic (CARTO, Biosense Webster) left and right atrial (RA) volumes (LAV(ECHO) vs. LAV(CARTO) and RAV(ECHO) vs. RAV(CARTO)) in patients undergoing catheter ablation for LSPAF. The study enrolled 173 consecutive subjects (females: 21 %, age: 59+/-9 years). There was only modest correlation between LAV(ECHO) (92+/-31 ml) and LAV(CARTO) (178+/-37 ml) (R=0.57), and RAV(ECHO) (71+/-29 ml) and RAV(CARTO) (173+/-34 ml) (R=0.42), respectively. LAV(ECHO) and RAV(ECHO) underestimated LAV(CARTO) and RAV(CARTO) with the absolute bias (+/-1.96 standard deviation) of -85 (-148; -22) ml and -102 (-169; -35) ml, respectively, and with the relative bias of -48 (-75; -21) % and -59 (-88; -30) %, respectively (all P<0.000001 for their mutual difference). Significant confounders of this difference were not identified. In patients with LSPAF, 2D echocardiography significantly underestimated both LA and RA volumes as compared with electroanatomic reference. This disagreement was independent of clinical, echocardiographic and mapping characteristics.

[Impaired Healing after Surgery for Femoral Fractures]. / Poruchy hojení po operacní lécbe zlomenin stehenní kosti.

PURPOSE OF THE STUDY: The aim of the study was to analyse causes of impaired bone healing in femoral fractures and to present options of their management. MATERIAL AND METHODS: This is a retrospective study of the data on complications prospectively collected between 2008 and 2013. The patients admitted for primary treatment at the Trauma Centre of the Faculty of Medicine in Hradec Kralove from January 2008 to December 2013 included 1186 patients with injury severity scores (ISS) > 15 and 1340 patients with new injury severity scores (NISS) >15, all older than 16 years. With the exception of two patients, the primary treatment involved the application of an external fixator as part of damage control surgery. Definitive surgery, regardless of the site of fracture, was performed using unreamed femoral nails (UFN) in 51, distal femoral nails (DFN) in 33, plates in 26, long proximal femoral nail antirotation (PFNA-long) in 14 and nails combined with dynamic hip screw (DHS) plates in five fractures. The analysis revealed both mechanical and biological causes of poor bone healing. RESULTS: Of the 124 patients whose multiple injuries included a fracture of the femur, 11 died within 24 hours in spite of intensive resuscitation. In the remaining 113 patients there were 16 bilateral fractures, 20 fractures of the proximal femur (extraarticular), 72 diaphyseal femur fractures and 26 distal femur fractures. Nine patients sustained segmental femoral shaft fractures. Ten diaphyseal and 14 distal femur injuries were open fractures (13.5% and 54%, respectively). Pseudarthrosis developed in a total of 12 fractures (9.3%); six (7.2%) were diaphyseal fractures, of which three were initially open fractures, and six (21.4%) were distal femur fractures with two initially open injuries. All proximal femur fractures healed completely. DISCUSSION: The frequency of non-union femoral diaphyseal fractures in our patients treated by unreamed intra-medullary nailing is in agreement with the literature data. The frequency of non-union distal femur fractures in our group was slightly higher than is published in the literature. This can be accounted for by the characteristics of our group consisting of patients with multiple severe injuries in whom fractures are due to high-energy trauma; the overall severity of injuries negatively affects the biological potential of a human organism for bone healing. CONCLUSIONS: A successful outcome of femoral fracture repair is based on an understanding of the biomechanical principle, i.e., correct fracture reduction and stable osteosynthesis fitting the morphology of the fracture. Comminuted femoral fractures heal well with the use of a narrow long nail whose working length allows for even distribution of movement at a fracture line amongst the fragments and thus fracture motion load does not exceed 20%. On the other hand, short oblique and transverse fractures are examples of problematic fractures which require maximum possible stability provided by a thick nail with a short working length; this is achieved by reaming the medullary cavity or adding lag screws. In our group of patients these fractures were also the most problematic ones. Generally, nailing remains the golden standard in the management of femoral fractures.

Distribution of mean cycle length in cavo-tricuspid isthmus dependent atrial flutter.

Although cycle length (CL) constitutes a fundamental descriptor of any arrhythmia, there is not larger study describing mean CL in electrophysiologically confirmed cavo-tricuspid isthmus (CTI)-dependent atrial flutter (AFL). We analyzed retrospectively digital recordings of 121 patients (98 men; age 64+/-11 years) referred for radiofrequency ablation of persistent CTI-dependent AFL. Median of mean AFL CL was 240 ms (interquartile range (IQR) of 222-258 ms, overall range of 178-399 ms). The distribution of CL was not normal (Shapiro Wilk test, p<0.001). Both counterclockwise and clockwise (14.9 % of all cases) AFLs were comparable in their CL; 240 (IQR 222-258) ms vs. 234 (217-253) ms, respectively. AFL CL<200 ms and AFL CL<190 ms was noticed in 5 (4.1 %) and 3 cases (2.5 %), respectively. In multivariate regression analysis, age (increase by 6+/-3 ms per decade of age, p=0.036), treatment with specific antiarrhythmic drugs (increase by 11+/-6 ms, p=0.052) and the history of cardiac surgery (increase by 26+/-9 ms, p=0.004) were independently associated with AFL CL. In conclusions, the distribution of AFL CL is not normal. The prevalence of AFL with short CL is low. Short CL<200 ms does not rule out the CTI-dependent AFL, especially in young and otherwise healthy patients.

[Improving of treatment safety in emergency thoracic surgery]. / Zvýsení bezpecnosti lécby v emergentní hrudní chirurgii.

Authors point out a possibility of improving operative results in thoracic surgery with acute state. They prove it with two groups of patients, where preoperative complications are anticipated. The first group consists of the patients with thorax injury and the second group consists of the patients with relapsing pneumothorax. With a blunt thorax injury is the surgical treatment often performed on blood-soaked pulmonary tissue or on parenchyma affected by ARDS. A necessary stapler suture during an atypical reaction is accompanied by bleeding or air-leak from the resected area. To reinforce the suture, there are used various materials for staplers to utilize a padding effect. Sometimes is necessary to use tissue sealants to prevent the air-leak. Traumacel Stapler Seam Protection meets requirements on the stapler suture reinforcement and, moreover, due to its bactericidal and haemostatic effects helps the tissue healing.

[Monitoring the effectiveness of surgical treatment of malignant pleural effusions]. / Monitorace efektivity chirurgické lécby maligních pleurálních výpotku.

BACKGROUNDS: Recurrent pleural effusion occured in 10% of cancer patients. Repeated thoracocentesis or drainage may be complicated by pneumothorax, haemothorax or pleural cavity infection. Thoracoscopic talc poudrage is one of the most effective pleurodesis technique in patients with malignant pleural effusions. The effectiveness of such pleurodesis is reaching the 70 to 90%. This surgical approach also allows to take a biopsy for histological verification of the process. An effort to predict the success rate of chemical pleurodesis on the basis of the body's general inflammatory reaction rate, which is determined by the dynamics of values of humoral and cellular inflammatory parameters in both serum and in pleural effusion. PATIENTS: In the period 6/2008-12/2009 we applied biotalcum to 14 patients with malignant pleural effusions. The group of patients consisted of 10 male patients and 4 female patients of average age 71 years. Indication to include patients in the group was a second or further thoracic puncture, shortening of the interval between interventions, estimated time of survival > 3 months and the possibility of operation under selective pulmonary ventilation. METHOD: We performed the collection of pleural effusion and blood serum at 12-hour intervals. The first collection was performed preoperatively before biotalcum application, and then during the time of losses from thoracic drainage bigger than 150 ml in 24 hours. The duration of thoracic drainage was 4 days +/- 1 day. The success of the treatment was observed by ultrasound scan before drainage removal; during the first three months always at intervals of 1 month and then after 3 and 6 months, depending on the progression of a disease. RESULTS: No reccurence occured when the P-CRP (pleural) and S-CRP (serum) ratio exceeded 60% during the first 48 hours after pleurodesis. On the other hand, when the ratio fall bellow 30-35%, the effusion relapsed frequently. CONCLUSION: The P-CRP/S-CRP ratio as a promising marker of talc pleurodesis effectiveness and monitoring both P-CRP and S-CRP levels is inexpensive and acceptable method for clinical practice. The pleural effusion caused by malignant mesothelioma appeares to be resistant to talc pleurodesis.

[Videothoracoscopy, standard and uncommon indications]. / Videotorakoskopie, standardní a méne casté indikace.

The authors' communication deals with standard cases of the application of thoracoscopy in the diagnostics and treatment. On the Cardiological Clinic of the Medical School of the Charles University and University Hospital in Hradec Králové they performed in the period 2000-2004 153 out of 837 operations using thoracoscopy (18.3%) and 22 using video assisted thoracoscopy (2.6%). Apart from the standard indications the authors mention two rare thoracoscopies when extracting a foreign body from the thorax and lungs.

[Long-term results of surgical treatment in lung cancer]. / Dlouhodobé výsledky chirurgické lécby plicní rakoviny.

The surgical treatment of lung cancer has got a long tradition at our department. The aim of this work is to evaluate the group of 3,857 patients from the years 1948-1997. The special analysis has been performed of the group of 1572 patients from the years 1974-1997 undergoing lung resection. Evaluating our operation policy a strong trend from pneumonectomy to less extensive operations can be found. The introduction of bronchoplastic operations and modern diagnostic methods has substantially improved the possibility of surgical treatment. The utilization of TNM system enabled to compare the different groups of patients according to the unified classification. The long term survival was directly related to the stage and histological type of disease. The five years period survived 33% of patients in whom the lung resection was performed during the period 1974-1997. The operative hospital mortality has been substantially reduced to 1.7%. Even though it is our duty to provided the surgical treatment to all the patients if the resection is still possible the best results are to be expected in patients in the first stage of disease. Therefore the early diagnosis followed by adequately sized resection without delay offers the best chance for the patients long term survival.

[Control of blood loss with topical administration of aprotinin after pulmonary tissue decortication and pleurectomy]. / Ovlivnení krevních ztrát po dekortikaci plicní tkáne a pleurektomii lokální aplikací aprotininu.

The authors were prospectively monitoring postoperative blood loss in 23 patients, in which decortication of the lung tissue and pleurectomy was performed and in which 500,000 KIU of aprotinin was applicated locally to the operating field before closing chest. The study was performed between the years 1998 and 2001. The amount of blood loss was compared to that of a group of 23 patients who underwent the same type of surgery between 1991 and 1998 without use of aprotinin. The postoperative blood loss was monitored 6, 12 and 24 hours after completing the surgery. Postoperative blood loss was lower in the group of patients in which aprotinin was used which was found to be statistically significant compared to the group of nonaprotinin patients.

DNA topoisomerase II-alpha in pulmonary carcinoid tumors.

Fifty-four pulmonary carcinoid tumors of surgically treated patients were diagnosed according to modified Arrigoni histological criteria (WHO 1999). Forty-seven typical (TC) and seven atypical carcinoids (AC) formed the basic groups. Four subgroups were selected from the TCs and consisted of cases with higher tumor size (T2) or those associated with nodal involvement (N1), tumor satellites, and tumorlets. Subgroup tumors were regarded as affections with possible increased proliferation potential. The proliferate activity was examined immunohistochemically by topoisomerase II-alpha (clone SWT3D1) on paraffin material and calculated by the number of positive nuclei per 10 HPF. The topoisomerase expression was found to be statistically different in both principal groups made up of typical and atypical carcinoids with a mean value of 49 and 135 positive nuclei per 10 high power field in TC and AC, respectively. The remaining subgroups of the TCs associated with examined characteristics (larger tumor diameter, metastases, satellites, tumorlets) were not found to be statistically different. The topoisomerase II-alpha is a marker giving valuable information about the diagnosis of pulmonary typical and atypical carcinoids.

[Surgical treatment of lung cancer]. / Chirurgická lécba plicní rakoviny.

The surgical treatment of lung cancer has got a long tradition at our department. The aim of this work is to evaluate the group of 3,727 patients from the years 1948-1995. The special analysis has been performed of the group of 1,456 patients from the years 1974-1995 undergoing lung resection. Evaluating our operation policy a strong trend from pneumonectomy to less extensive operations can be found. The introduction of bronchoplastic operations and modern diagnostic methods has substantially improved the possibility of surgical treatment. The utilization of TNM system enabled to compare the different groups of patients according to the unified classification. The long term survival was directly related to the stage and histological type of disease. The five years period survived 32% of patients in whom the lung resection was performed during the period 1974-1995. The operative hospital mortality has been substantially reduced to 2%. Even though it is our duty to provide the surgical treatment to all the patients if the resection is still possible the best results are to be expected in patients in the first stage of disease. Therefore the early diagnosis followed by adequately sized resection without delay offers the best chance for the patients long term survival.

[Proliferative activity in pulmonary carcinoids]. / Proliferacní aktivita plicních karcinoidu.

AIM: On the basis of known Ki-67 dependence on tumor malignancy in some lesions, we compared this marker expression quantitatively in pulmonary typical and atypical carcinoid tumors and attempted to predict their biological behavior especially in cases associated with tumorous lymphadenopathy, satellites, and carcinoid tumorlets. METHOD: Using material from surgically treated patients, we examined 54 cases of pulmonary carcinoids divided into five groups. 1. Forty-two typical carcinoids (TC), 2. Twelve atypical carcinoids (AC) diagnosed according to modified Arrigoni's criteria (Travis et al., 1998), 3. Thirty-two TC without metastases, satellites, and tumorlets (M, S, T), 4. Eight AC without M, S, T, and 5. Fourteen TC and AC associated with M, S, T. Groups 3, 4, and 5 were formed of cases selected from group 1 and 2. The proliferate activity was evaluated by Ki-67 (MIB-1, Immunotech France, 1:25). Its nuclear labeling was counted in more than 50 HPF and calculated as a number of positive nuclei in 10 HPF. The Fisher exact test was used for statistical analysis. RESULTS: The Ki-67 nuclear expression was found in 19 (45%) out of 42 TC and in 9 (75%) out of 12 AC. In the set of TC without metastases (M, S, T), the Ki-67 positive labeling was found in 14 (44%) out of 32 cases (group III) and in six (75%) out of eight AC (group IV). In all TC and AC tumors with M, S, T (group V), the Ki-67 expression was encountered in 8 (57%) out of 14 cases. The Fisher exact test showed no significant difference between all examined groups. CONCLUSION: No statistically significant difference was found in Ki-67 expression in pulmonary typical and atypical carcinoids. It appears to be a factor which can not be used for tumor prognosis prediction or adjuvant therapy indication in surgically treated patients.

Long- and medium-chain triacylglycerols in nutritional support of liver regeneration of partially hepatectomized rats.

An appropriate choice for a suitable diet during liver regeneration still remains an enigma. To investigate the effect of isocaloric enteral feeding with medium-chain triacylglycerols (MCT) and long-chain triacylglycerols (LCT) supplement (MCT+LCT, 40%:60% w:w) (178 kJ/kg b.w./24 h), rat liver regeneration was studied 24 and 72 h after partial hepatectomy. The liver DNA synthesis 24 h after partial hepatectomy was significantly higher in the MCT+LCT-supplemented rats (30.2+/-8.2 x 10(3) dpm/mg liver DNA) compared to MCT-treated animals (18.1+/-5.7 x 10(3) dpm/mg liver DNA). Liver protein synthesis was non-significantly elevated both 24 and 72 h after surgery in MCT+LCT-supplemented rats (13.7+/-1.1 and 10.9+/-3.1 x 10(3) dpm/mg liver protein). Seventy-two hours after partial hepatectomy, the hepatocyte mitotic activity was significantly increased in MCT+LCT- supplemented group vs. LCT- or MCT-fed rats (3.3+/-0.7 vs. 1.9+/-0.7 or 1.0+/-0.6 mitoses per 1000 hepatocytes), thus exhibiting an increased proliferative potential. The results showed a qualitative difference according to the proportion of MCT to LCT in the enteral supplements. Overfeeding with MCT decreased body weight, increased liver weight by its fatty infiltration, increased rat mortality rate and reduced spontaneous caloric intake. We conclude that the balanced supplement of MCT+LCT (40%:60% w:w) preserves liver regeneration, whereas overfeeding with MCT seems to be deleterious.

Surgery for bullous emphysema.

The present indications for surgery are mainly large or increasing bullae that result in compression of apparently good lung tissue, and the complications of bullous diseases such as pneumothorax. The results of local resection of localized giant bullae are dramatic. The resection of small bullae generally has little effect on lung function. Lobectomy should not be done until bullae have been removed locally and the remaining lung has been tested by positive ventilation. The indications for the resection of large bullae in the presence of diffuse emphysema require very careful individual study. Pulmonary function tests are mandatory but computed tomography is the single most useful method of assessing the extent of the bullous disease and the underlying lung disease. If the underlying lung is diffusely cystic then any surgical treatment is palliative only.

[Results of open valvotomy in congenital stenosis of the aortic valve]. / Výsledky otevrené valvotomie pro kongenitální stenózu aortální chlopne.

Between 1977 and 1992 at the Cardiosurgical Clinic of the Faculty Hospital in Hradec Králové on account of congenital valvular aortic stenosis 142 patients were subjected to catheterization. Valvotomy of a stenotic aortic valve was performed in 69 patients. The submitted paper evaluates the progression of aortic stenosis based on investigations of the aortic gradient and the area of the aortic orifice in repeatedly catheterized patients before and after valvotomy and evaluates also the results of surgery after a 1-15-year interval after surgery.

[Satellite cells in pulmonary carcinoid tumorlets and carcinoids]. / Satelitní bunky v plicních karcinoidových tumorletech a karcinoidech.

Pulmonary tissue of twenty-four patients with carcinoid tumorlets and twenty-three typical carcinoid tumors was studied immunohistochemically for stellate-shaped S-100 protein positive (sustentacular) cells. Sustentacular cells (SCs) have been calculated per 10,000 tumorlet or carcinoid elements. The presence of SCs was proved in 18 subjects (75%) of all examined tumorlet cases with quantitative frequency between 13 and 196 SCs per 10,000 tumorlet cells. These elements were also found in 18 carcinoid tumors (79%) of all 23 investigated cases with quantitative frequency between 5 and 927 SCs per 10,000 carcinoid cells. The cluster analysis showed two separate clusters in both groups of lesions with strikingly high frequency of SCs, i.e., from 66 up to 196 SCs/10,000 tumorlet elements and from 138 up to 923 CSs/10.000 carcinoid cells, respectively. SCs may not be used as an indicator of biological behaviour of pulmonary neuroendocrine tumors for their a broad frequency spectrum in examined benign lesions, i.e. tumorlets and typical carcinoid tumors.

S-100 protein positive (sustentacular) cells in pulmonary carcinoid tumorlets: a quantitative study of 24 cases.

Stellate-shaped S-100 protein positive sustentacular cells (SCs) appear to correlate inversely with the degree of tumor malignancy in some neuroendocrine tumors. Therefore, the SCs have been investigated in carcinoid pulmonary tumorlets and subsequently examined quantitatively in order to provide a basis for estimation of this phenomenon in tumorlet related lesions, especially carcinoids and neuroendocrine carcinomas. Pulmonary tissue from twenty-four patients with carcinoid tumorlets was studied immunohistochemically for S-100 protein positive SCs together with glial fibrillary acidic protein, actin, desmin, vimentin and cytokeratins. Tumorlet SCs were calculated per 10,000 tumorlet elements. The presence of SCs was proven in 18 subjects (75%) of all examined cases with quantitative frequency between 13 and 196 SCs per 10,000 tumorlet elements. The histogram showed three separate clusters of cases. Cluster 2 and cluster 3 with strikingly high frequency of SCs, i.e. from 66 up to 196 SCs per 10,000 tumorlet cells, may represent the biphasic differentiation potential of tumorlet elements. The mentioned lesions could be regarded as the possible precursors of pulmonary paragangliomas or paraganglioid carcinoids.