Atypical Histopathological Aspects of Common Types of Lung Cancer-Our Experience and Literature Review

Lung cancer is among the most common oncological diseases regarding incidence and mortality, with most of these having epithelial origins. Pathological reporting of these tumors is conducted according to the 5th edition of the World Health Organisation (WHO) classification of thoracic tumours. This study aims to draw the pathologist's attention to four rare, atypical microscopic aspects that some of the most common types of lung malignancies reveal upon standard evaluation (hematoxylin-eosin stain) that make histopathological diagnosis challenging: acantholytic, pseudoangiosarcomatous, signet ring cell, and clear cell features. Each of these aspects was exemplified by a case diagnosed in the pathology department of the "Marius Nasta" Institute. Furthermore, we analyzed the classification dynamics of different WHO editions and used PubMed to review articles written in English and published in the last eleven years on this subject. Pathologists should be familiar with these unusual aspects to avoid misdiagnoses and to ensure the correct classification of tumors, which is extremely important because these tumor phenotypes have been associated with specific molecular alterations and a worse clinical evolution. There is a need to clarify the histogenesis and associated genetic mutations, given the fact that the rarity of these tumor phenotypes makes their study difficult. Some authors consider these to be overlapping entities; however, we do not encourage this, as they may exhibit different prognoses and various molecular alterations with important therapeutic implications. The signet ring cell feature was associated with ALK rearrangement in lung adenocarcinoma; thus, these patients can benefit from tailored therapy with ALK-tyrosine kinase inhibitors (ALK-TKI). Recent studies associated clear cell morphology with FGFR3-TACC3 fusion, suggesting that patients with this diagnosis may be potentially eligible for FGFR inhibitors. We described, for the first time, the pseudoangiosarcomatous pattern in a case of lung adenocarcinoma; to our knowledge this aspect has only been described until now in the context of squamous cell carcinomas.

P898 Role and evolution of the right ventricle in heart failure patients treated with cardiac resynchronization therapy delivered by left ventricle pacing alone

Funding Acknowledgements

This work was supported by CREDO Project - ID: 49182, financed through the SOP IEC -A2-0.2.2.1-2013-1 cofinanced by the ERDF.

Background

Cardiac resynchronization therapy (CRT) is an effective treatment for patients with heart failure (HF) with reduced ejection fraction. Biventricular pacing is the most common mode of delivering CRT. However, several studies have demonstrated non-inferiority of LV pacing alone. There are several trials about the role and evolution of right ventricle (RV) systolic function in CRT patients delivered by biventricular pacing showing that RV function is an independent predictor of long-term outcome following CRT, and improvement in RV function after CRT.

Purpose

To examine if RV function and dimensions prior to CRT could have an impact on CRT response and assessment of the evolution of RV function after 1 year follow up in patients with LV pacing alone.

Methods

22 patients with a mean age of 63 ± 10.6 years including 9 (40,9%) females and 13 man (59,1%), with HF (EF < 35%, LBBB > 120 ms, or non-LBBB > 150 ms, with NYHA II to IV) were enrolled and underwent CRT implantation LV pacing alone . Each patient benefited from standard two dimensional (2D) echocardiography, tissue Doppler imaging, with assessment of Left ventricular (LV) end-diastolic (LVEDV), and end-systolic volumes (LVESV), ejection fraction, RV maximum basal (RVD basal), TAPSE, fractional area change (FAC), and tricuspid lateral annular systolic velocity (S′) , RV TEI index , RV systolic pressure using Bernoulli equation, at inclusion before CRT and 12 ± 2 months after CRT implantation. Patients presenting with reductions of LVESV of >15% were termed volumetric responders for further statistical analysis and patients with reduction of NYHA class were termed clinical responders.

Results

14 patients (63.63 %) cases were volumetric responders and 21 patients were clinical responders showing an improvement in NYHA class at one year. 1 patient died. Among echocardiographic parameters of RV: RVD basal , TAPSE , FAC , TEI index, RV systolic pressure (p < 0.01) were good predictors for volumetric response proving that a dilated RV with poor systolic function may be a predictor for non response to CRT even in patients with LV alone pacing. TAPSE and FAC have the best AUC for prediction of response to CRT therapy.We proposed cutoff values for predicting response versus non response to CRT therapy TAPSE 16.6mm (AUC 0.827, 95% CI, p < 0.05, sensibility 100%, specificity 71.4% ) and FAC 36% (AUC 0.826, 95%CI, p < 0.05, specificity 91%, sensibility 66%) and RVD basal 37,5mm (AUC 0.805, 95%CI, p = 0.03, sensibility 63%, specificty 85%). In volumetric non-responders, RV function improves at one year follow up with an increase in TAPSE (p = 0.008) and a decrease of RV TEI index (p = 0.04).

Conclusions

LV pacing alone CRT improves RV systolic function and may account for clinical benefit in patients without LV function improvement at one year follow-up. RV systolic function and dimensions before CRT implantation could predict response to LV pacing alone CRT therapy.