Utility of chest CT for differentiating primary and secondary achalasia

•CT is a useful technique for differentiating primary and secondary achalasia.•Nodular/lobulated distal oesophageal wall thickening favors secondary achalasia.•A soft-tissue mass at the gastroesophageal junction favors secondary achalasia.•Pulmonary, hepatic, or osseous metastases favor secondary achalasia.

AimTo determine the computed tomography (CT) findings of primary and secondary achalasia and to assess the utility of CT for differentiating these conditions.MethodsA computerized search revealed 13 patients with primary achalasia and 15 with secondary achalasia who underwent chest CT during a 10-year period. The images were reviewed to determine whether there was distal oesophageal narrowing (including the length/contour of narrowing), oesophageal dilation, oesophageal wall thickening (including degree/symmetry/pattern of thickening), a soft-tissue mass at the gastro-oesophageal junction, mediastinal adenopathy, or other findings of malignant tumour.ResultsEleven (85%) of 13 patients with primary achalasia had distal oesophageal narrowing at CT that was smooth in all patients; four (31%) had oesophageal wall thickening that was smooth and symmetric in all patients; none had a soft-tissue mass at the gastro-oesophageal junction or mediastinal lymphadenopathy; and two (15%) had pulmonary metastases from unrelated lung cancers. In contrast, 12 (80%) of 15 patients with secondary achalasia had distal oesophageal narrowing at CT; 11 (73%) had distal oesophageal wall thickening that was nodular/lobulate and asymmetric in seven (64%) and smooth and symmetric in four (36%); six (40%) had a soft-tissue mass at the gastro-oesophageal junction; seven (47%) had mediastinal lymphadenopathy; and all 15 had other findings of malignant tumour.ConclusionCT is a useful technique for differentiating primary and secondary achalasia. Distal oesophageal wall thickening that is nodular/lobulate and asymmetric, a soft-tissue mass at the gastro-oesophageal junction, mediastinal lymphadenopathy, and pulmonary, hepatic, or osseous metastases are findings that favour secondary achalasia.