Endometrial Adenocarcinoma Associated With Elevated Serum ...

Clinical Chemistry / FREE β-HCG FROM AN ENDOMETRIAL ADENOCARCINOMA

Endometrial Adenocarcinoma Associated With Elevated Serum Concentrations of the Free β Subunit of Human Chorionic Gonadotropin David G. Grenache, PhD,1 Karen A. Moller, MD,2 and Pamela M. Groben, MD1 Key Words: Human chorionic gonadotropin; hCG; Tumor marker; Endometrial adenocarcinoma DOI: 10.1309/LMR6YEJLP6QCDX93

Abstract We report a case of a histologic grade II endometrial adenocarcinoma without trophoblastic differentiation in a 24-year-old woman with an elevated serum concentration of human chorionic gonadotropin (hCG) and with no evidence of pregnancy. Serum and urine specimens were used to study the hCG immunoreactivity. Qualitative tests performed on serum and urine using 5 different assays produced conflicting results. The hCG concentration in serum and urine was quantified using assays designed to detect different molecular forms of the molecule; analysis revealed that serum hCG immunoreactivity was due entirely to the presence of the free β subunit. Immunohistochemical analysis performed on tissue samples showed strong cytoplasmic staining for hCG. While hCG is a wellrecognized tumor marker in gynecologic malignant neoplasms, immunoreactivity most often is due to the presence of both intact molecule and the free β subunit. To our knowledge, this is the first report of an endometrial adenocarcinoma producing only the free β subunit of hCG.

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Am J Clin Pathol 2004;121:748-753 DOI: 10.1309/LMR6YEJLP6QCDX93

Human chorionic gonadotropin (hCG), a glycoprotein hormone composed of 2 dissimilar subunits designated α and β, normally is produced by the syncytiotrophoblastic cells of the placenta. While most often used to diagnose pregnancy, the serum concentration of hCG also has clinical usefulness as a marker for trophoblastic disease and germ cell tumors.1 There also are reports of hCG positivity in the serum of patients with nontrophoblastic, nongonadal gynecologic malignant neoplasms2 and in patients with ductal adenocarcinoma of the pancreas, biliary cancer, and carcinoma of the bladder, cervix, lung, colon, and kidney.3-6 hCG immunoreactivity in these nontrophoblastic cases often is due to the presence of intact hCG and the free β subunit, and the incidence of tumors that produce only the free β subunit is small. We report a case of endometrial adenocarcinoma that was associated with serum hCG immunoreactivity due entirely to the free β subunit.

Case Report The patient was a 24-year-old, morbidly obese woman who initially was given a diagnosis of clinical stage I, histologic grade I endometrial cancer in November 2001. She initially was treated with progestational agents at increasing doses; however, repeated endometrial sampling showed progression to histologic grade II endometrial cancer despite prolonged exposure. Therefore, it was recommended she undergo primary radiotherapy for what then was a clinical stage I, persistent grade II endometrial cancer. Whole abdominal imaging could not be done because of her morbid obesity and space constraints on the machines. © American Society for Clinical Pathology

Clinical Chemistry / CASE REPORT

At the initiation of radiation therapy, she reported being the victim of a sexual assault 2 weeks earlier. A serum specimen submitted for a quantitative hCG produced a result of 56 mIU/mL (56 IU/L; reference interval,