Gastrointestinal stromal tumor masquerading as a lung neoplasm. A case presentation and literature review

Gastro-Intestinal Stromal Tumors (GISTs) belong to the group of gastrointestinal mesenchymal tumors (GIMTs). These include myogenic tumors (leiomyomas or leiomyosarcomas), neurogenic tumors (schwannomas) and GISTs. They arise from the gastrointestinal (GI) wall, and they are distributed from the esophagus to the rectum. [1-4]These are now defined as spindle cell, epithelioid or occasionally pleiomorphic mesenchymal tumors that express c-kit protein immunopositivity (CD117), which is their major diagnostic criterion. [2,3,5]Although generally rare, they are the most common mesenchymal neoplasms of the GI tract, and encompass most tumors previously classified as gastric and intestinal smooth muscle or neural cell tumors [1,2].A 58 year old lady was referred by her General Practitioner (GP) after presenting with a 3 day history of moderate left sided pleuritic chest pain radiating to the left shoulder, low grade pyrexia and frontal headaches. She experienced no cough, hemoptysis, or shortness of breath but had recurrent episodes of upper respiratory tract infections in the past five months. There was no significant past medical history and she was a lifetime non smoker.Clinical examination revealed left lower lobe crackles. Routine blood tests revealed a White Cell Count of 11.82 109/lt and a C-Reactive protein (CRP) of 164 mg/lt. The chest radiograph (CxR) demonstrated a raised left hemi diaphragm with volume loss in the left lower lobe (Fig 1).Due to the equivocal findings on the CxR, she underwent a Computerized Tomography (CT) (Fig 2,) of her thorax which revealed a large necrotic mass within the left lower lobe extending into the posterior mediastinum, surrounding the aorta and in close contact with the distal esophagus. It extended to the gastric fundus through extensive invasion of the left hemi-diaphragm. No mediastinal lymphadenopathy was reported.A CT guided biopsy was performed and the histology showed a spindle cell tumor. Immunohistochemistry revealed the