Unidentical Double Trouble- A Rare Case Report

Collision tumours are relatively rare entities and are thus, not well recognised. Collision tumour can be defined as two coexisting but histologically different malignancies involving the same organ or adjacent organ with an equivocal intermediate transitional zone between them. Collision tumours of the lung and oesophagus are very rare. Such cases are diagnosed by Computerised Tomogram (CT) Scan or Chest X-Ray for complaint of dysphagia. Definitive diagnosis is made by tissue biopsy. Here, a 66-year-old male is admitted for evaluation of an anterior mediastinal mass. Radiology revealed an anterior mediastinal mass extending in to the left hilar region and upper lobe of right lung anteriorly and in to the lower end of oesophagus posteriorly. Biopsy was performed. Microscopically, transbronchial biopsy revealed a cellular lesion, composed of round-to-oval cells with streaming nucleus, positive for Immunohistochemistry (IHC) markers, CD-56 and Synaptophysin pertaining to a diagnosis of small cell carcinoma. Biopsy of the oesophageal growth shows nest of dysplastic squamous epithelium which infiltrates into underlying muscularis propria showing features of a squamous cell carcinoma. Multiple fragments of squamous epithelium are also seen with necrotic tissue in vicinity and acute inflammatory exudate. Few cells show multinucleation, molding and margination of chromatin, showing the characteristic morphological features of Herpes oesophagitis. The patient was administered platinum-based Chemotherpy.