Ans. A. Achalasia cardia. (Harrison's Medicine, 18th ch. 292; /Fig. 292-5).Achalasia cardia- Megaesophagus/sigmoid esophagus- "Bird beak" deformity- Absence of primary peristalsis below level of cricopharyngeus- Hurst phenomenon (temporary transit through cardia when hydrostatic pressure of barium column is above toxic LES pressure)- Vigorous achalasia (numerous tertiary contractions in non-dilated distal esophagus of early achalasia).Hiatus hernia- Epiphrenic bulge- >4 longitudinal coarse thick gastric folds above gastroesophageal junction or in the suprahiatal pouch- A Schatzki or B ring if present, is pathognomonic of a hiatal hernia because it marks the junction between squamous and columnar epithelium and represents the Z line.- Distance between B ring and hiatal margin > 2 cm- Peristalsis causes above hiatus.Schatzki ring (B ring/Lower esophageal mucosal ring, seen as a thin, web-like annular constriction at the esophagogastric junction is associated with a small hiatal hernia.Lye stricture(alkali/caustic strictures) - Long, tight and smooth stricturePeptic stricture- Short and tubular narrowing.Carcinoma oesophagus- Typical annular narrowing with overhang- ing margins and destruction of the mucosa.- 'Rat-tail' esophagus- Shouldering signLeomyoma/GIST- Smooth filling defect with right angles of origin from the esophageal wall (Submucosal smooth lesion)Cytomegalovirus esophagitis- iant ovoid flat ulcers (vasculitis of submucosal vessels)- Gastroesophageal junction with adjacent part of stomach is commonly affected.Herpes esophagitis- Discrete superficial punctate/linear serpentine/stellate/diamond shaped ulcers.Candidial esophagitis- Cobble stone mucosa- 'Shaggy' contour of the esophagus with small diffuse superficial ulcers- Irregular plaque-like filling defectsTertiary esophageal contractions (presbyesophagus, diffuse esophageal spasm, neuromuscular diseases)- "Corkscrew" appearance- "Rosary-bead/Shish kebab" configuration- "Yo-Yo" motion of bariumScleroderma- Esophageal shortening- Sliding hiatus hernia- Hidebound esophagus