The value of SATB2 in the differential diagnosis of intestinal-type mucinous tumors of the ovary: primary vs metastatic

Primary mucinous adenocarcinomas of the ovary are a diagnostic challenge because their histologic and immunohistochemical features usually overlap with metastatic tumors. SATB2 is a recently identified protein with restricted expression in the glandular cells lining the lower gastrointestinal tract. The aim of this study is to examine the differential expression of SATB2 in primary and metastatic tumors of the ovary. Mucinous ovarian tumors of intestinal type were retrieved from the pathology files of the Instituto Nacional de Cancerología de México. A double reading of the hematoxylin and eosin–stained slides was performed to confirm the diagnosis, and a detailed review of the clinical chart was performed to define the primary origin of the tumor (ovarian vs metastatic). Immunohistochemical staining for CK20, CDX2, and SATB2 was performed and evaluated by 2 gynecopathologists. A total of 106 mucinous tumors were identified, 26 of which were considered to be metastatic, and 80 of which were primary ovarian tumors. All of the primary tumors that were not associated with cystic teratomas were negative for SATB2, and the 4 that were associated with a teratoma were positive for SATB2. All 20 of the metastatic tumors of the colon and appendix were positive for CK20, and 4 were positive for CK7. In addition, all 20 of these tumors were positive for SATB2, and 19 were positive for CDX2. SATB2 appears to be a useful marker for the diagnosis of primary vs metastatic mucinous intestinal-type neoplasms and is highly sensitive in detecting lower gastrointestinal tract metastasis.