Pseudomyxoma peritonei

This protocol is intended to assist pathologists in providing clinically useful and relevant information as a result of the examination of surgical specimens. Use of this protocol is intended to be entirely voluntary. If equally valid protocols or similar documents are applicable, the pathologist is, of course, free to follow them. Indeed, the ultimate judgment regarding the propriety of any specific procedure must be made by the physician in light of the individual circumstances presented by a specific patient or specimen.

It should be understood that adherence to this protocol will not guarantee a successful result. Nevertheless, pathologists are urged to familiarize themselves with the document. Should a physician choose to deviate from this protocol or similar documents based on the circumstances of a particular patient or specimen, the physician is advised to make a contemporaneous written notation of the reason for the procedure followed.

The College recognizes that this document may be used by hospitals, attorneys, managed care organizations, insurance carriers, and other payers. However, the document was developed solely as a tool to assist pathologists in the diagnostic process by providing information that reflects the state of relevant medical knowledge at the time the protocol was first published. It was not developed for credentialing, litigation, or reimbursement purposes. The College cautions that any uses of the protocol for these purposes involve considerations that are beyond the scope of this document.

PROTOCOL FOR THE EXAMINATION OF SPECIMENS FROM PATIENTS WITH TUMORS OF THE PERITONEUM

EXPLANATORY NOTES

A: Histologic Type.-This protocol refers only to primary tumors of the peritoneum. Secondary tumors, including those causing pseudomyxoma peritonei (usually of appendiceal origin), are not addressed by these guidelines. It is possible, however, that "peritoneal spread" of some ovarian serous borderline tumors may reflect independently primary peritoneal rather than metastatic ovarian neoplasia in some cases.

Classification of Peritoneal Tumors

Benign

Adenomatoid tumor

Benign multicystic mesothelioma (multilocular peritoneal inclusion cyst)

Mesothelial cysts) (unilocular) (free or attached)

Well-differentiated papillary mesothelioma

Solitary fibrous tumor (fibrous mesothelioma)

Malignant

Diffuse malignant mesothelioma

Epithelial type

Sarcomatous type

Biphasic type

Undifferentiated

Rare types*

Serous tumor of borderline malignancy (of low malignant potential)^1,2

Serous carcinoma^^3-5

Malignant tumors of other mullerian types

Desmoplastic small round cell tumor

Soft tissue-type tumors

1. Both ovaries are either normal in size or enlarged by a benign process. In the judgment of the surgeon and the pathologist, the bulk of the tumor is on the peritoneum, and the extent of tumor involvement at 1 or more extraovarian sites is greater than that on the surface of or within either ovary.

2. Microscopic examination of the ovaries reveals (a) no tumor; (b) tumor confined to the surface epithelium with no evidence of cortical invasion; (c) tumor involving the ovarian surface and the underlying cortical stroma but less than 5 x 5 mm in diameter; or (d) tumor less than 5 x 5 mm within the ovarian substance, with or without surface involvement.

3. The histologic and cytologic characteristics of the tumor are predominantly serous and similar or identical to those of ovarian serous papillary carcinoma of any grade.

4. If an oophorectomy has been performed in the past, a confident diagnosis of primary peritoneal serous carcinoma requires 1 of the following: (a) a pathology report to document the absence of carcinoma in the ovarian specimen, with review of all the slides if the oophorectomy has been performed within 5 years of the current procedure; (b) if the oophorectomy has been performed more than 5 years before the current procedure, the pathology report of the specimen should be obtained, and the slides should be reviewed if still available. The peritoneal tumor should be interpreted in light of the ovarian findings.

B: Histologic Grade.-There is no established grading system for most peritoneal tumors, but the degree of differentiation is incorporated into the terminology of some of them. Serous and other mullerian-type tumors can be graded according to the criteria used for similar tumors in the female genital tract (see protocols on ovary6 and endometrium7).

C: Staging of Peritoneal Tumors.-There is no widely accepted staging system for peritoneal tumors, but their extent may have prognostic significance. Thus, it is important to determine whether a mesothelioma is unifocal, multifocal, or diffuse,8 and whether there are lymph node or distant metastases. Peritoneal serous carcinomas are generally staged as though they were stage II to stage IV ovarian cancers (see protocol for ovary).6

* Rare types include desmoplastic, small cell, lymphohistiocytoid, and deciduoid types.

^ When this tumor involves the extraovarian peritoneum significantly and the ovarian surface minimally or not at all, it is generally considered to be of peritoneal origin.

^^ The Gynecological Oncology Group has adopted the following criteria for the diagnosis of primary peritoneal serous carcinoma:

References

1. Bell DA, Scully RE. Serous borderline tumors of the peritoneum. Am I Surg Pathol. 1990;14:230-239.

2. Biscotti CV, Hart WR. Peritoneal serous micropapillomatosis of low malignant potential (serous borderline tumors of the peritoneum): a clinicopathologic study of 17 cases. Am I Surg Pathol. 1992;16:467-475.

3. Gilks CB, Bell DA, Scully RE. Serous psammocarcinoma of the ovary and peritoneum. Int J Gynecol Pathol. 1990;9:110-121.

4. Bloss JD, Liao S, Butler RE, et al. Extraovarian peritoneal serous papillary carcinoma: a case-control retrospective comparison to papillary adenocarcinoma of the ovary. Gynecol OncoL 1993;50:347-351.

5. Piver MS, )ishi MF, Tsukuda Y, Nava G. Primary peritoneal carcinoma after prophylactic oophorectomy in women with a family history of ovarian cancer: a report of the Gilda Radner Familial Ovarian Cancer Registry. Cancer. 1993;71: 2751-2755.

6. Scully RE, Henson DE, Nielsen ML, Ruby SG. Practice protocol for the examination of specimens removed from patients with ovarian tumors: a basis for checklists. Arch Pathol Lab Med. 1995;119:1012-1022.

7. Silverberg SG. Protocol for the examination of specimens from patients with carcinomas of the endometrium: a basis for checklists. Arch Pathol Lab Med. 1999;123:28-32.

8. Goldblum J, Hart WR. Localized and diffuse mesotheliomas of the genital tract and peritoneum in women: a clinicopathologic study of nineteen true mesothelial neoplasms, other than adenomatoid tumors, multicystic mesotheliomas, and localized fibrous tumors. Am J Surg Pathol. 1995;19:1124-1137.

Bibliography

Antman KH, Pass HI, Schiff PB. Benign and malignant mesothelioma. In: DeVita VT Jr, Hellman S, Rosenberg SA, eds. Cancer: Principles and Practice of Oncology. 5th ed. Philadelphia, Pa: JB Lippincott-Raven; 1997:1853-1878.

Battifora H, McCaughey WTE. Tumors of the Serosal Membranes. Washington, DC: Armed Forces Institute of Pathology; 1995. Atlas of Tumor Pathology, 3rd series, fascicle 15.

Russell P, Farnsworth A. Surgical Pathology of the Ovaries. 2nd ed. New York, NY: Churchill Livingstone; 1997.

Scully RE, Young RH, Clement PB. Tumors of the Ovary, Maldeveloped Gonads, Fallopian Tube, and Broad Ligament. Washington, DC: Armed Forces Institute of Pathology; 1998. Atlas of Tumor Pathology 3rd series, fascicle 23.

Robert E. Scully, MD; Karen H. Antman, MD; for the Members of the Cancer Committee, College of American Pathologists

Accepted for publication May 2, 2001.

From the James Homer Wright Laboratories, Massachusetts General Hospital, Boston, Mass (Dr Scully); and the Division of Medical Oncology, Columbia-Presbyterian Medical Center, New York, NY (Dr Antman).

This protocol was developed by the Cancer Committee of the College of American Pathologists and submitted for editorial review and publication. It represents the views of the Cancer Committee and is not the official policy of the College of American Pathologists.

Reprints: See Archives of Pathology & Laboratory Medicine Web site at www.cap.org.

Copyright College of American Pathologists Sep 2001
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