An inflammatory myofibroblastic tumor (IMT) is a very rare tumor of mesenchymal origin with unclear etiopathogenesis, no unique diagnostic features, and no specific management protocol. It is often confused with inflammatory pseudotumor in literature, and the distinction needs further study. The average size, recurrence risk, and metastatic potential differ as per the site of origin. The abdomen is a very rare site for IMTs. Hepatic IMTs (H-IMTs) are reported to be solid tumors with sizes ranging from 1 cm to 20 cm in literature, and gastric IMTs (G-IMTs) range from 3 cm to 10 cm in size and can be solid-cystic. We report here a case of a 36-year-old gentleman with a 34x27x17 cm solid-cystic lesion in the lesser sac with loss of fat planes with stomach and left hemi-liver. The patient was managed by complete surgical resection of the lesion with wedge gastrectomy and wedge hepatectomy and recovered uneventfully. To our knowledge and based on our literature review, this case presents the largest reported and solid-cystic G-IMT with the involvement of left hemi-liver in a young gentleman and discusses its management as well as the relevant literature on this rare entity. This clinical presentation of G-IMT should be kept in the differential diagnosis in a relevant case presenting in the future. Immunohistochemistry is a must to establish the diagnosis, and surgical resection to negative margins is the management option of choice in resectable cases.