The Stealthy Masquerade: Metastatic Gastric Adenocarcinoma Mimicking Hepatic Steatosis on Histopathology – A Diagnostic Challenge

Metastatic carcinoma to the liver can exhibit striking histomorphological similarity to benign hepatic pathology, leading to diagnostic pitfalls. Distinguishing such entities is critical for accurate patient management. We report the case of a 53-year-old woman presenting with a 3-month history of abdominal pain and fullness. Imaging revealed a suspected gastric malignancy with hepatic, skeletal, and nodal metastases. Liver biopsy was performed to evaluate hepatic lesions. Histopathological examination demonstrated cords of cells closely resembling steatotic hepatocytic cell plates with pericellular fibrosis in one biopsy core. However, this focus was devoid of portal tracts. Immunohistochemistry (IHC) revealed strong cytokeratin (CK) 7 positivity, along with positivity for BerEp4 and MOC31, and negativity for CK20, CDX2, and HepPar1. This immunoprofile confirmed metastatic adenocarcinoma of probable gastric origin. Notably, extensive extramedullary hematopoiesis was observed within hepatic sinusoids, implicating a compensatory hematopoietic response secondary to bone marrow involvement by the malignancy. This case highlights the critical need for careful histopathological evaluation of liver biopsies, corroborated by IHC in patients with known or suspected malignancy. Metastatic adenocarcinoma can closely mimic benign hepatic steatosis on routine histology, emphasizing the crucial role of an appropriate IHC panel in picking up such “stealthy metastasis.” Awareness of this pitfall ensures prompt and accurate diagnosis, directly influencing patient management.