Anastomosing haemangioma of the colon

Anastomosing haemangioma (AH) is a rare, benign variant of capillary usually occurring in the genitourinary system.1 AH easily confused with low-grade angiosarcoma2 due to its rarity, morphology, and identical radiological appearance. We present an unusual case incidentally found colon 55-year-old male. The patient underwent colonoscopy exclude microscopic colitis, 3 mm sessile rectal polyp was excised. contained circumscribed but unencapsulated submucosal lesion resembling splenic parenchyma, formed by multiple anastomosing sinusoidal sized spaces lined hyperchromatic endothelial cells frequent hobnail morphology. Unlike angiosarcoma, lacked significant atypia, spindling, multilayering, papillary tufting, mitotic activity necrosis. There were also thin intervening bands mildly cellular fibrous stroma, occasional fragmented erythrocytes, hyaline globules within macrophages. Immunohistochemical staining positive for marker CD24 negative D2-40, GLUT-1, CD8, HHV8. Molecular genetics confirmed guanine nucleotide-binding protein G(q) subunit alpha (GNAQ) mutation characteristic AH3. This demonstrates how immunohistochemistry, molecular can help distinguish from malignant differentials. By reporting this case, we aim increase awareness features facilitate accurate diagnosis prevent unnecessarily aggressive treatment. References 1. Zhao M, Li C, Zheng J, Sun K. hemangioma kidney: report rare subtype mimicking angiosarcoma review literature. Int J Clin Exp Pathol 2013; 6: 757–65. 2. Montgomery E, Epstein JI. tract: angiosarcoma. Am Surg 2009; 33: 1364–9. 3. Bean GR, Joseph NM, Gill RM, et al. Recurrent GNAQ mutations hemangiomas. Mod 2017; 30: 722–7.