Giant pelvic retroperitoneal liposarcoma: case report.

BACKGROUND: Pelvic retroperitoneal liposarcomas are rare tumors of mesenchymal origin. We present a case of a giant pelvic well-differentiated liposarcoma of the retroperitoneum in a woman, presenting with a large abdominal mass. CASE: A 62-year-old woman presented with a rapid abdominal enlargement. Pelvic examination revealed a huge mass occupying the whole pelvis and part of the right abdomen. At surgery, the pelvic organs were displaced to the right side by a retroperitoneal mass that marginally involved the part of the posterior abdominal wall, left parietal peritoneum of the diaphragm, left colic flexure and the left adnexa. The huge mass, uterus, and both adnexa were removed; hemicolectomy and latero-lateral anastomosis were carried out. No adjuvant irradiation was given. The patient is alive and free of disease five years after the operation. CONCLUSION: The gynecologist should consider retroperitoneal liposarcoma in the differential diagnosis of large pelvic or abdominal masses.

Stefin B, the major low molecular weight inhibitor in ovarian carcinoma.

Endogenous cysteine proteinase inhibitors (CPIs) presumably regulate lysosomal cysteine endopeptidases (CPs), such as cathepsins B and L, in vivo. An imbalance between CPs and CPIs in carcinomas, possibly due to impaired inhibition of proteinases, was reported. Ovarian carcinoma contain high levels of Stefin B and about twentyfold less Stefin A compared to normal epithelial tissue. Stefin B was isolated and characterized. We used alkaline treatment, affinity chromatography on Cm-papain Sepharose, followed by gel filtration and ion-exchange chromatography and anti-Stefin B-Sepharose 4B to isolate two major isoforms of Stefin B with pI values 5.9 and 6.5. M(r) of ovarian Stefin B was close to 14,000 as judged by SDS-PAGE and had a blocked N-terminus. It strongly inhibited papain (Ki = 0.11 nM) and cathepsin L (Ki = 0.035 nM), but only moderately cathepsin B (Ki = 130 nM). As these properties are similar to Stefin B from human and bovine origin, as well as to Stefin B from human histiosarcoma, we believe that tumor Stefin B does not differ from normal Stefin B.

Cystatins and stefins in ascites fluid from ovarian carcinoma.

Cysteine proteinase inhibitors (CpI) of all three families were found in ascites fluid from patients with ovarian carcinoma. CPIs were isolated by affinity chromatography on carboxymethylated papain Sepharose, followed by gel filtration, anti-stefin-Sepharose and ion exchange chromatography. The highest apparent inhibition against cathepsin B (Cat B) was found in the low molecular mass (LMM) CPI fraction. Immunochemical analysis of this fraction revealed the presence of cystatin C and both stefins A and B while the high molecular mass (HMM) CPI fraction contained kininogens. We demonstrated that CPIs were not completely associated with cysteine proteinases (CPs): about 20% of HMM CPIs and 50% of LMM CPIs were free in native ascites fluid. Affinity chromatography on anti-Cat B-Sepharose revealed that the major LMM CPI, associated with Cat B in native ascites fluid, was the full length form of cystatin C, pI 9.3, and not its truncated form, pI 7.85. The latter was isolated and found to inhibit Cat B in vitro with apparent Ki 0.18 +/- 0.2 nM. Stefin A was isolated from alkaline activated ascites fluid in its two isoforms, pI 4.6 and 4.9. In native ascites, the pI 4.9 isoform was mostly associated with Cat B. Ki for Cat B was 3.55 +/- 1.7 nM, not significantly different from the Ki values measured for stefin A, isolated from other human tissues and biological fluids.