Primary Gastrointestinal Stromal Tumor Presenting as an Isolated Lung Mass

Abstract

Gastrointestinal stromal tumors (GISTs) are rare gastrointestinal (GI) tumors, representing a small portion of soft tissue tumors of the abdominal cavity. Extraintestinal gastrointestinal stromal tumors (EGISTs) are uncommon forms of GISTs that present outside the GI tract. There have only been a rare number of reported cases of EGIST presenting above the diaphragm. We present the case of a 50-year-old female with shortness of breath, and found to have bilateral pleural effusions and left-sided lung mass. The initial lung mass aspiration was negative for malignancy; yet, pleural fluid was suggestive of malignancy, and repeat biopsy and immunohistochemical stain were diagnostic for GIST. Ultimately, the patient underwent videoassisted thoracoscopic surgery, pleurodesis with doxycycline, and adjuvant therapy with imatinib. This is a report of primary EGIST presenting as an isolated lung lesion with no involvement of the GI tract. In patients with suspected malignancy, it is of paramount importance to obtain a detailed history, including remote signs and symptoms, while performing a thorough work-up. Especially in the lung where initial biopsies can be skewed due to inflammation and atelectasis, repeat biopsies may be necessary to obtain an accurate diagnosis.