Production, analysis, and characterization of reference materials for prostate-specific antigen.

OBJECTIVE: To produce a set of three reference materials that mimic sera from patients with prostate disorders in the prostate-specific antigen (PSA) concentration range important for clinical screening for prostate cancer (approximately 0.5, approximately 4.0, and approximately 10.0 ng/mL), to analyze these reference materials in a large number of clinical laboratories using a variety of commercially available methods, and to characterize the molecular forms of PSA in them. METHODS: Units of serum from healthy individuals and from patients with varying degrees of elevated PSA were pooled, lyophilized, and distributed along with conventionally prepared, semen-supplemented proficiency testing samples to laboratories participating in the College of American Pathologists Basic Ligand Survey. The reference material and one of the standard Survey samples were fractionated by Sephacryl S-200-HR gel filtration chromatography. RESULTS: The Abbott IMx, Hybritech Tandem-E, Hybritech Tandem-R, and Tosoh AIA-Pack all measured PSA in the reference material fairly equally (agreement within +/- 12%). In contrast, the Abbott IMx results in the semen-supplemented Survey specimens were as much as 1.8-fold higher than the other three assays. Characterization of the molecular forms showed the reference material was approximately 90% alpha 1-antichymotrypsin-bound PSA, whereas the semen-supplemented Survey specimens were approximately 40% alpha 1-antichymotrypsin-bound PSA, which largely explained the difference in assay recoveries. CONCLUSIONS: Semen-free materials containing only endogenous PSA much more closely mimic real clinical specimens and should prove useful in efforts to standardize clinical PSA assays.

Retrovesical myxoid leiomyosarcoma.

An elderly man with a retrovesical leiomyosarcoma is described. This unusual tumor showed a prominent myxoid stroma. The smooth muscle origin of the malignant spindle cells was confirmed by ultrastructural study. Review of the literature has not yielded a similar case.

Ureteral endometriosis in post-menopausal women.

Ureteral obstruction secondary to endometriosis is an infrequently observed phenomenon, particularly in post-menopausal women. Two patients with obstructive uropathy, aged fifty-five and seventy-four, underwent ureteroplasty procedures with pathologic documentation of endometriosis. The possible pathogenetic mechanisms of ureteral endometriosis and previously reported cases are cited.