Abstract
Clear cell adenocarcinoma generally develops in the kidneys, ovaries, extraovarian endometriosis, uterine cervix, upper vagina, and lower genital tract. A 62-year-old woman was referred to our hospital because of lower abdominal pain and a high fever. Enhanced computed tomography showed a huge intrapelvic mass, 7 cm in diameter, with abscess formation. After antibiotic therapy, the patient underwent en bloc resection with sigmoid colectomy, hysterectomy, left oophorectomy, and left ureterectomy. Histological examination of the resected specimen showed a clear cell adenocarcinoma. Immunohistochemical stains showed the tumor cells to be strongly positive for cytokeratin (CK)20 and CDX4, partially positive for CK7 and CD10, and negative for ER, PgR, and NapsinA. Because the positive staining for CK20 and CDX4 demonstrated a typical adenocarcinoma of the colon, metastatic clear cell carcinoma from kidney or ovarian tissue was ruled out. Since magnetic resonance imaging and positron emission tomography showed no other tumors, the patient was diagnosed with primary clear cell adenocarcinoma of the sigmoid colon. The patient's postoperative course was uneventful, and, one year later, the patient had no unusual clinical features and no evidence of recurrence. Surgical resection is the generally recommended treatment for primary clear cell adenocarcinoma of the colon.
