Clear cell carcinoma in a background of endometriosis. Case report of a finding in a midline abdominal scar 5 years after a total abdominal hysterectomy

BACKGROUND: Endometriosis is considered a premalignant process whose association with carcinoma is well documented. We discuss a case of clear cell carcinoma with an unusual presentation in that it was located outside the abdominal cavity and was the only lesion noted clinically and radiologically. The histopathologic diagnostic criteria will be reviewed, as will the association of carcinomas with endometriosis. Furthermore, we will review the current literature of extraovarian clear cell carcinoma associated with endometriosis with regard to clinical outcome. CASE: A 42-year-old Hispanic woman presented to the Fine Needle Aspiration (FNA) Clinic at Parkland Hospital, Dallas, Texas, in August 2005 secondary to a growing area of firmness associated with her midline abdominal hysterectomy scar. A single mass anterior to the abdominal wall was identified radiologically. The FNA sample was reported as highly atypical cells suspicious for adenocarcinoma. Excision of this mass revealed a clear cell carcinoma in a background of endometriosis. CONCLUSION: Clear cell carcinoma is one of the most prevalent carcinomas associated with endometriosis, whether identified in the ovary or extraovarian site. This case is perplexing because the mass was a solitary lesion and the patient never had documented endometriosis. The unusual presentation may make survival difficult to predict.