Epithelial granuloma occurring on the staple-stump after segmentectomy for ovarian cancer lung metastasis

When a mass occurs at the staple line following lung resection, it can be difficult to distinguish between local cancer recurrence and granuloma. We present a case of a staple-line granuloma with 18F-fluorodeoxyglucose-positron emission tomography uptake and elevated serum carbohydrate antigen 19-9 (CA19-9) in a patient with ovarian cancer lung metastasis. After granuloma resection, serum CA19-9 levels normalized, and CA19-9 positive cells were identified in the resected tumor. Therefore, serum CA19-9 elevation does not rule out a staple-line granuloma. Whereas granulomas on computed tomography (CT) scans tend to show smooth shadows along the staple line unilaterally, detailed CT evaluation may help diagnostic differentiation. Differentiation based on imaging and tumor markers has limitations. However, core needle biopsy has the risk of misdiagnosis and tumor cell dissemination, therefore surgical resection should be considered when comprehensive findings indicate a potential recurrence.