Clinically aggressive pseudomyxoma peritonei: a variant of a histologically indolent process.

BACKGROUND: Three distinct morphologic types of pseudomyxoma peritonei syndrome have been defined: disseminated peritoneal adenomucinosis (DPAM), peritoneal mucinous carcinoma (PMCA), and a hybrid morphologic type. Prognosis is best in patients with DPAM; unfortunately, some patients with DPAM succumb to a rapidly progressive disease process. METHODS: We identified a subset of 11 patients with a histopathology of DPAM but a clinical course showing an invasive disease process. As a comparison group, from a database of 501 patients with pseudomyxoma peritonei, we selected 22 age- and sex-matched controls with a DPAM histology who are alive with no evidence of disease. Clinical factors were identified for comparison of case and control groups. Expression of mucin antigens, mucin (MUC)1 and MUC2, were evaluated using immunohistochemistry. RESULTS: The study group consisted of 11 patients (five men and six women), with a median survival of 52.2 months (SD 7.46) and a 31% 5-year survival. All 22 matched control cases (10 men and 12 women) are alive and disease-free. Clinical data on the study and control groups including co-morbidity were similar. No significant difference in the expression of MUC1 (P = 0.74, Fisher's exact test) or MUC2 (P = 0.34, Fisher's exact test) was demonstrated between groups. CONCLUSIONS: Further investigation of pseudomyxoma peritonei at a molecular and genetic level may help to formulate a more comprehensive classification.

Recent advances in immunohistochemistry in the diagnosis of ovarian neoplasms.

This leader reviews recent advances in immunohistochemistry that are useful in the diagnosis of ovarian neoplasms. These include the value of different anticytokeratin antibodies in the distinction between a primary ovarian adenocarcinoma and a metastatic adenocarcinoma, especially of colorectal origin. These antibodies have also helped to clarify the origin of the peritoneal disease in most cases of pseudomyxoma peritonei. The value of antibodies against so called tumour specific antigens, such as CA125 and HAM56, in determining the ovarian origin of an adenocarcinoma is also reviewed. In recent years, several studies have investigated the value of a variety of monoclonal antibodies in the diagnosis of ovarian sex cord stromal tumours and in the distinction between these neoplasms and their histological mimics. These antibodies include those directed against inhibin, CD99, Mullerian inhibiting substance, relaxin like factor, melan A, and calretinin. Of these, anti-alpha inhibin appears to be of most diagnostic value. It is stressed that these antibodies should always be used as part of a larger panel and not in isolation.

Immunohistochemical evidence supporting the appendiceal origin of pseudomyxoma peritonei in women.

Women with pseudomyxoma peritonei (PMP), characterized by multifocal mucinous implants (disseminated peritoneal adenomucinosis), often have synchronous appendiceal and ovarian mucinous tumors. There has been considerable debate as to whether the ovarian tumors are secondary to the appendiceal tumor or are independent primary ovarian tumors; the latter are usually classified as mucinous tumors of low malignant potential (MLMP). It has been reported that cytokeratins (CK) 7, 18, and 20, carcinoembryonic antigen (CEA), and human alveolar macrophage 56 (HAM-56) are useful markers for distinguishing primary ovarian neoplasms from metastases of intestinal origin. Nearly all primary ovarian MLMP tumors and mucinous carcinomas are positive for CK 7, 18, and 20, CEA, and HAM-56, whereas most colorectal adenocarcinomas are negative for both CK 7 and HAM-56 and positive for CK 20 and CEA. Thirteen appendiceal and 14 ovarian mucinous tumors from 14 cases of PMP and 11 primary ovarian MLMP tumors were studied immunohistochemically for expression of CK 7, 18, and 20, monoclonal and polyclonal CEA (mCEA and pCEA), and HAM-56. Of 14 cases of PMP, 10 (71.4%) had identical staining patterns for all antibodies in both the appendiceal and ovarian tumors. For eight of these, the pattern of immunoreactivity was characterized by negative reactions for CK 7 and HAM-56 and positive reactions for CK 18 and 20, mCEA, and pCEA. One additional case for which only the ovarian tumor could be stained had the same pattern. The remaining two cases were also positive for CK 18 and 20 and CEA, but in addition were positive for CK 7. Two cases were discordant only for CK 7 and one case was discordant for both CK 7 and HAM-56. All 11 MLMP tumors were positive for CK 7 and 18, and pCEA. Eight (72.7%) of 11 were positive for HAM-56, mCEA, and CK 20. There was a statistically significant difference in the frequency of immunoreactivity for CK 7 (p = 0.0005) and HAM-56 (p = 0.0002) between the ovarian mucinous tumors in PMP and the MLMP tumors, with the ovarian tumors in PMP tending to be negative for CK 7 and HAM-56, similar to the appendiceal adenomas. Most ovarian mucinous tumors in PMP demonstrate a pattern of immunoreactivity with CK 7, 18, and 20, CEA, and HAM-56 that is identical to the associated appendiceal adenoma and distinct from primary ovarian MLMP tumors, consistent with the interpretation that these ovarian tumors are secondary to the appendiceal tumor.

[Pseudomyxoma peritonei in females. 13 personal cases. Practical deductions from a review of 420 cases in the literature]. / La maladie gélatineuse du péritoine chez la femme. Treize observations personnelles. Déductions pratiques à partir de la revue de 420 cas de la littérature.

Having considered their 13 cases of pseudomyxoma peritonei where mucin is found in the peritoneum, the authors reviewed 420 cases abstracted from the literature. It is a rare condition (2 out of every 10,000 laparotomies) and is three times more common in women than in men. the mean age is 53 years. The spontaneous evolution of the condition before the diagnosis is made is about 21 months, as the aetiology and histology may be confusing. Diagnosis is made easier by paracentesis, but ultrasound and now tomodensitometry, are very helpful. It is interesting that in 5 out of the 13 cases there was a rise in carcino-embryonic antigen (C.E.A.) both in the gelatinous material and in the serum. Five cases out of the 5 appendix tumours or tumours of the ovary which were benign showed this feature. The level of C.E.A. in the serum was weak (50-150 ng/ml) when the quantity of gelatinous material was large (48,000-70,000 ng/ml). In one case a step-ladder rise in C.E.A. corresponded to clinical changes. Finally, the proof that C.E.A. was secreted by the cells of a cyst adenoma of the ovary could have been brought about by the phenomenon of immuno-competition. The following therapeutic measures are proposed: first surgery and then the use of proteolytic enzymes with, in benign lesions, estimations of C.E.A. and tomodensitometry. This last examination makes it possible, in cases of recurrences, to separate the "young" forms which can still be sensitive to enzyme treatment, from the "old" forms which are resistant to such treatment and may be respond better to chemotherapy.