The Distinction Between Primary and Metastatic Mucinous Carcinomas of the Ovary

Abstract

The gross and routine microscopic features of 25 stage I primary mucinous ovarian carcinomas without clinical evidence of recurrence and 25 mucinous carcinomas metastatic to the ovaries were compared. Findings that were frequent in the latter and strongly favored a metastasis were: 1) bilaterality, 2) microscopic surface involvement by epithelial cells (surface implants), and 3) an infiltrative pattern of stromal invasion. Findings that were less frequent but present exclusively or almost exclusively in metastatic carcinomas were: 1) a nodular invasive pattern, 2) ovarian hilar involvement, 3) single cell invasion, 4) signet-ring cells, 5) vascular invasion, and 6) microscopic surface mucin. Findings that were frequent in, and strongly favored, primary ovarian carcinoma were: 1) an "expansile" pattern of invasion and 2) a complex papillary pattern. Findings that were less frequent but also favored a primary tumor were: 1) size >10 cm, 2) a smooth external surface, 3) benign-appearing and borderline-appearing areas, 4) microscopic cystic glands, and 5) necrotic luminal debris. Findings that did not distinguish the tumors were: 1) a cystic gross appearance, 2) gross solid, papillary, necrotic, or hemorrhagic areas, 3) nature of cyst contents (mucinous vs nonmucinous), 4) stromal mucin (pseudomyxoma ovarii), 5) cribriform, villous, or solid growth patterns, 6) focal area resembling typical colonic carcinoma, 7) goblet cells, or 8) tumor grade. Primary and metastatic mucinous ovarian carcinomas can be distinguished from each other in the great majority of cases based solely on their conventional histopathologic findings. Careful gross evaluation is also important with special attention paid to the external surface of the ovarian tumor(s) to detect abnormalities that have the features of surface implants on microscopic evaluation.

Use of novel immunohistochemical markers expressed in colonic adenocarcinoma to distinguish primary ovarian tumors from metastatic colorectal carcinoma

“…The classification of the tumors into primary vs metastasis was reviewed using established histologic criteria 3,17 and in cases of putative primary tumors where morphologic findings were not diagnostic, clinical records were reviewed to confirm absence of a gastrointestinal primary on follow-up.…”

“…2,17,19,20 This important distinction has clinical implications for accurate staging of the tumor as well as for therapeutic options. Recent studies have highlighted the salient morphologic features helpful in distinguishing a primary from a metastatic tumor, 3,20 however, occasionally immunohistochemical studies may be very helpful as supportive evidence in the above differential diagnosis. Differential staining with CK7 and CK20 in conjunction with morphology and clinical information is usually adequate in ascribing a primary site in the majority of the cases 4,6,7,9,10 however, a small percentage of primary ovarian adenocarcinomas, most often mucinous or endometrioid subtypes may be difficult to distinguish from a colorectal metastasis using differential cytokeratin expression.…”

“…2 Distinguishing primary ovarian adenocarcinoma, particularly endometrioid and mucinous subtypes, from metastatic tumors from the colon can be challenging. 3 In the past decade, numerous markers with differing specificity and sensitivity have been evaluated in the above differential diagnosis. [4][5][6][7][8] The use of differential cytokeratin expression using cytokeratin 7 (CK7) and cytokeratin 20 (CK20) in this group of tumors is of great value, although limited by the frequent expression of cytokeratin 20 in primary mucinous tumors of the ovary (reported to be up to 60% in some studies) and the coexpression of CK7 by a small subset of primary colonic adenocarcinomas.…”

Distinguishing primary from secondary mucinous ovarian tumors: an algorithm using the novel marker DPEP1

“…3,4,19,20 Unfortunately, in many cases, the diagnosis is not straightforward because many morphological features are shared by primary and secondary ovarian tumors. 7 The aim of this research was to develop a protocol to more accurately distinguish primary mucinous ovarian cancer from ovarian metastasis of digestive organ cancer, including colorectal and non-colorectal cancer.…”

“…3 In problematic cases, the diagnosis has been made by integrating clinical, radiological, serological, and pathological features. 4 Recently, immunohistochemistry, especially cytokeratin 7 (CK7) and cytokeratin 20 (CK20) staining, has been widely used to distinguish primary from secondary ovarian tumors. 5,6 Although immunohistochemistry has been useful in diagnosis of some cases, current immunohistochemical markers are not sufficient to diagnose all secondary ovarian tumors.…”