Left Lung Agenesis with Bicuspid Aortic Valve

Address for correspondence: Dr. Shachi Jain Taran E-mail: shachitaran@yahoo.co.in Dr. Shachi Jain Taran, MBBS, MD, Assistant Professor, Department of Paediatrics, Sri Aurobindo Medical College and PG Institute, Indore, India, 2Dr. Ravindra Kumar, PhD, Central Research Laboratory, Sri Aurobindo Medical College and PG Institute, Indore, India, 3Dr. Manish Lodha, MD, Department of Radiodiagnosis, Synergy Hospital, Indore, India. Abstract


Introduction
M ajor congenital anomalies of lung such as hypoplasia and agenesis are very rare en ty and seldom being reported 1 . They have varied clinical presenta on ranging from totally asymptoma c to severe respiratory insuffi ciency. Lung agenesis and or hypoplasia o en misdiagnosed or underdiagnosed on radiograph because of its similarity with other more common medical condi ons like collapse, pleural eff usion, mucous plug, foreign body and pnuemonectomy etc.

The Case
A 17 year old female presented to our clinic with complaints of backache since 5-6 days a er some weightli ing. On examina on she had mild drooping of le shoulder and scoliosis with convexity towards right in high thoracic spine. On respiratory system examina on chest movement on le side were decreased with decreased vocal fremitus and dull note on percussion. Ausculta on showed breath sounds were absent in most of the le lung fi elds but there was no respiratory distress. Trachea and heart were shi ed to le side. X-ray Chest [ Fig 1A], spine AP and lateral revealed opaque le hemithorax with crowding of ribs in superior area with mild scoliosis. On taking history retrospec vely she had history of fa gue but there was no history of dyspnea, weight loss, loss of appe te, or any other respiratory symptom. Since clinical examina on and x-ray fi ndings were not matching. Pa ent was advised computed tomography scan chest which revealed crowding of ribs on le side, medias nal shi to le , le pleural cavity absent, le lung, le main bronchus and le pulmonary artery not seen, le diaphragm high up [ Fig 1B to 1E]. Trachea was on right side with compensatory emphysema and hypertrophy of right lung, right pulmonary artery and its branches were normal. Bony cage was normal except for crowding of ribs on le side. All these fi nding were compa ble with le pulmonary agenesis. Pulmonary func on test result was sugges ve of restric ve lung disease. On 2D echocardiography, bicuspid aor c valve and only two pulmonary veins draining into le atrium were seen. Main pulmonary artery bifurca on could not be visualized. No other congenital anomaly was found.

Discu ssion
Agenesis of lung is extremely rare congenital anomaly fi rst described by De Pozze, who discovered it accidently in 1673 at the autopsy of an adult female 2 . It is thought to have an incidence of approximately 1 in 100000 children 3 . In India fi rst case was reported by Muhamed in 1923 which was also an autopsy fi nding 4 . With the advancement of diagnos c modali es detec on of such cases during life has risen considerably.
Lung agenesis is the result of failure of the development of respiratory system from foregut during embryogenesis. Type and severity of defect depend on the me of insult during organogenesis. Arrest at the stage of primi ve lung bud produces bilateral lung agenesis. The insult at later stage may lead to unilateral agenesis. Lobar agenesis occurs when development arrest happens in one side of older embryo. Pulmonary hypoplasia may occur during the last trimester of pregnancy with failure of fi nal alveolar diff eren a on 5 .
The primary causes of pulmonary hypoplasia includes some role of TTF-1, hepatocyte nuclear factor HNF310, epidermal growth factor and its receptor (EGFR) and secondary causes includes small fetal thoracic volume, prolonged oligohydramnios, decreased fetal breathing, congenital heart diseases and trisomies 18, 13, 21 6 .     (c) Group III-Presence of variable amounts of bronchial tree, pulmonary parenchyma and suppor ng vasculature Le pulmonary agenesis is o en an isolated fi nding but recently, Di George syndrome and velo-cardiofacial syndrome have been reported in associa on with le pulmonary agenesis 9,10 . Cardiovascular anomalies are usually acyano c but rarely anomalous pulmonary venous return, tetralogy of fallot, and single ventricles are also reported. Nearly 50% cases of right pulmonary agenesis have associated congenital defects which usually involve cardiovascular, skeletal, gastrointes nal and genitourinary system 11 . Congenital absence of breast is rare 12 .
The onset of symptoms in pulmonary agenesis is remarkably variable. In many cases, presence of this anomaly usually comes to light during infancy because of recurrent chest infec ons, cardiopulmonary insuffi ciency or due to associated congenital anomalies. However, pa ents with one lung have been reported to survive well into adulthood without much complaints and oldest pa ent was 72 years old 13 . Prognosis in such cases depends upon two things -fi rstly severity of associated congenital anomalies, secondly involvement of normal lung in other disease process.
Our pa ent is among those rare cases of le lung agenesis with bicuspid aor c valve who is asymptoma c ll now as per respiratory symptomatology is concerned. This was an incidental diagnosis in a case of backache which was probably due to scoliosis. This pa ent belonged to group 1 of Boyden classifi ca on as there was no le main bronchus and le pulmonary artery. To best of our knowledge no other case of le lung agenesis with bicuspid aor c valve has been reported ll now.

Conclusion
Whenever coming across a case of one hemithorax opacity and clinical fi nding do not match radiograph, we must include rare condi ons like unilateral lung agenesis into our diff eren al diagnosis.