Neoplasms of the Lung MCQs

Differential cyanosis (cyanosis only in lower extremities) is seen in a patient with patent ductus arteriosus (PDA) when there is reversal of shunt. There is a right-left shunt from the pulmonary artery to the aorta just distal to the left subclavian artery. This is Eisenmenger's syndrome. Coarctation causes radiofemoral delay and a lower blood pressure in the leg as compared to the arm. It may be associated with PDA but there is no suggestion in this patient. Continuous machinery murmur is the classic murmur of PDA but when the shunt reverses (as in patients with a large PDA and/or pulmonary disease) the murmur becomes softer and shorter. When Eisenmenger's syndrome has developed surgery is associated with a very high mortality. Reference: Harrison's Principles of Internal Principles, 20 th edition, ch:264 pg:1838,1839

Ebstein's anomaly is associated with maternal exposure to lithium carbonate in the first trimester . It causes malformed tricuspid valve leading to tricuspid regurgitation. Option 1 - VSD is the most congenital heart disease. Option 2 - In the vast majority of cases of neonates with complete heart block the cause is unknown but in the minority it may be caused by autoimmune disease, particularly Anti-Ro antibodies, in the mother. Option 4 -In hypoplastic left heart syndrome, LV hypolasia occurs as the left sided chambers fail to develop and blood enters the systemic circulation from the right ventricle via the pulmonary artery and a patent ductus arteriosus. Reference: Braunwald's heart disease 12 th edition, page no.1559

Nearly 90% of SCLCs harbor mutations in TP53 and RB1. Reference: Harrison's Principles of Internal Medicine, 21 st ed, Ch: 78, Pg: 597

CD 56, NCAM, synaptophysin and Chromogranin are neuroendocrine markers and will be positive in small cell carcinoma lung. Nap-A and TTF 1 are other immunohistochemical markers that can be used in the diagnosis of lung cancer. Primary lung adenocarcinoma (Nap-A positive, TTF-1 positive) Primary lung squamous cell carcinoma (Nap-A negative, TTF-1 negative) Primary SCLC (Nap-A negative, TTF-1 positive). Cytokeratins 7 and 20 used in combination can help narrow the differential diagnosis; nonsquamous NSCLC, SCLC, and mesothelioma may stain positive for CK7 and negative for CK20, whereas squamous cell lung cancer often will be both CK7 and CK20 negative Reference: Harrison's Principles of Internal Medicine, 21 st ed, Ch: 78, Pg: 596

Explanation: Marfan syndrome is an autosomal dominant connective tissue disorder caused by mutations in the FBN1 gene on chromosome 15, which encodes fibrillin-1 , an important component of elastic fibres. Defective fibrillin leads to abnormal connective tissue, causing skeletal (tall stature, long limbs), ocular (lens subluxation), and cardiovascular manifestations (aortic root dilation, dissection) . Explanation of other options: FGFR3 (Option B): Mutation causes achondroplasia , leading to short-limb dwarfism, not Marfan's tall stature. COL1A1 (Option C): Mutations cause osteogenesis imperfecta , characterised by brittle bones, blue sclera, and hearing loss. TSC1 (Option D): Mutation causes tuberous sclerosis , a neurocutaneous syndrome with cortical tubers, seizures, and skin lesions.

Cyanotic heart disease with decreased pulmonary blood flow: TOF Pulmonary atresia with intact ventricular septum Tricuspid atresia Double outlet right ventricle TGA with Pulmonary stenosis and VSD Ebstein anomaly Cyanotic heart disease with increased pulmonary flow: D TGA D TGA with intact ventricular septum TGS with VSD L TGA DORV with PS DORV with malposition of arteries (Taussig Bing anomaly) Total anomalous pulmonary venous return Tricuspid atresia Single ventricle Hypoplastic left heart syndrome

Cyanotic congenital heart diseases Tetralogy of Fallot (most common) Persistent truncus arteriosus Transposition of great arteries Total anomalous pulmonary venous connection Tricuspid atresia Ebstein anomaly Eisenmenger syndrome Pulmonary arteriovenous malformation Examples of non-cyanotic heart diseases include ASD, VSD, PDA, coarctation of aorta, pulmonary stenosis etc. Reference: Harrison's Principles of Internal Principles, 20 th edition, ch:256 pg:1804,1805

Syndromes associated with PDA: Edward syndrome (Trisomy 18- ASD, VSD) Patau syndrome (Trisomy 13 - ASD, VSD) Cri du chat syndrome (deletion of 5p) Noonan syndrome (Pulmonary stenosis, HCM, ASD) Congenital rubella syndrome Cardiac manifestations of Marfan syndrome include Mitral valve prolapse, Aortic root dilatation, Aortic regurgitation, Aortic dissection (rarely) Reference: Harrison,s Principles of Internal Principles, 20 th edition, ch:264 pg:1833