Nongynecologic metastases to fallopian tube mucosa: a potential mimic of tubal high-grade serous carcinoma and benign tubal mucinous metaplasia or nonmucinous hyperplasia

Our plain-English summary of Nongynecologic metastases to fallopian tube mucosa: a potential mimic of tubal high-grade serous carcinoma and benign tubal mucinous metaplasia or nonmucinous hyperplasia, by J.T. Rabban, P. Vohra, C.J. Zaloudek (The American Journal of Surgical Pathology, 2015).

The study

• Authors: J.T. Rabban, P. Vohra, C.J. Zaloudek
• Journal: The American Journal of Surgical Pathology
• Published: 2015;39(1):35-51
• Cited by: 50 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Mucosal alterations of the fallopian tube are generally thought to represent alterations of the native tubal mucosal epithelium, whether benign or malignant. The current paradigm implicating the fallopian tube fimbriae as the origin of most pelvic high-grade serous carcinomas (HGSCs) is based on the premise that HGSC growing within the tubal mucosa originated there. This has fueled proposals to redefine classification rules for assigning the primary site of origin on the basis of the presence or absence of HGSC in the tubal mucosa. The corollary is that it is unlikely for metastatic carcinoma to grow within fallopian tube mucosa. Evidence to support or refute this corollary is minimal, in part because the fallopian tubes historically have been ignored. This study reports the pattern and topography of 100 nongynecologic cancers that metastasized to the fallopian tubes. Most tumors were adenocarcinoma (87%), and the remainder included lymphomas, neuroendocrine tumors, and mesotheliomas. The most common primary origins of tumor were the colon (35%) and breast (15%). Gross evidence of a tubal nodule or mass was only seen in 35% of cases. Ovarian metastases were present in 95% of cases, although 23% did not exhibit gross evidence of metastasis. Tumor involved the fimbriae in 49% of cases, including 10% of cases in which the tumor was restricted to the fimbriae without involving the nonfimbriated portion of the tube. The anatomic distribution of metastases included the tubal mucosa (29%), submucosa (43%), muscularis (54%), serosa (76%), lymphovascular spaces (38%), intraluminal space (16%), and mesonephric remnants (39%). The most common architectural pattern of mucosal growth was a flat layer (22/29 cases), followed by varying degrees of stratification, tufting, and papillary growth. High-grade atypia was present in 18/29 cases of mucosal growth, resulting in patterns that resembled primary tubal HGSC. Accompanying growth in the tubal submucosa frequently produced a pseudoinvasive pattern mimicking invasive tubal HGSC. Immunohistochemical expression of p53 by 8/18 high-grade mucosal metastases further contributed to the resemblance to primary tubal HGSC. Bland cytology was present in 11/29 cases of mucosal growth, some of which also exhibited mucinous features, resulting in patterns that resembled either tubal mucinous metaplasia or nonmucinous tubal hyperplasia. Although uncommon, it is possible for metastases of nongynecologic cancers to grow within the mucosa of the fallopian tube and create a potential diagnostic pitfall. Intramucosal growth of a tumor in the fallopian tube is not pathognomonic of a primary tubal origin of the tumor. These findings may carry implications for proposed criteria using the status of the fallopian tube mucosa to assign primary origin of a gynecologic cancer.

In plain English

This was a pathology case series from the University of California San Francisco. The authors searched their pathology database from 1991 to 2013 for cancers that had started outside the female reproductive organs and spread to the fallopian tube, and found 100 patients. The article did not study asbestos or any other exposure. Most tumors were adenocarcinoma (87%). The colon (35%) and breast (15%) were the most common origins, and 2 tumors were peritoneal mesotheliomas. The ovaries were also involved in 95 of 100 patients, but the tubes looked suspicious to the naked eye in only 35 of 100. Tumor grew in the inner lining (mucosa) of the tube in 29 patients. In 18 of these 29, the cells were high grade and could resemble a primary tubal cancer (high-grade serous carcinoma). Eight of those 18 stained for p53, a marker used in that diagnosis. The other 11 looked bland and could resemble benign tubal changes. The authors concluded that tumor growing within the tubal lining is not indisputable evidence that the tumor began there.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Retrospective pathology case series (review of archived fallopian tube slides from an institutional pathology database)
• Who was studied: 100 patients with a cancer of nongynecologic origin that had spread to a fallopian tube, identified at the University of California San Francisco between January 1, 1991 and December 31, 2013; patients with primary ovarian, peritoneal or endometrial epithelial tumors were excluded
• Exposure: Not an exposure study. No asbestos, fiber or occupational exposure was assessed. The subject was the spread of nongynecologic cancers, including 2 peritoneal mesotheliomas, to the fallopian tube.
• Main results:
  • Among the 100 patients, the most common primary sites were the colon (35%), breast (15%), appendix (12%), stomach (9%) and pancreas (5%)
  • Among the 100 tumors, 87% were adenocarcinoma. The rest were lymphoma (5%), intestinal neuroendocrine tumor (4%), mesothelioma (2%, listed in the tables as peritoneal mesothelioma), urothelial carcinoma (1%) and gastrointestinal stromal tumor (1%)
  • Ovarian metastasis was present in 95 of the 100 patients with tubal metastasis
  • On gross examination, a suspicious excrescence, nodule, mass or matting by tumor was seen in the fallopian tubes of 35 of 100 patients
  • The fimbriae were involved by tumor in 49 of 86 patients (57%) whose specimens contained fimbriae
  • Tumor involved the tubal mucosa in 29 patients, the submucosa in 43, the muscularis in 54 and the serosa in 76
  • Of the 29 tumors growing in the tubal mucosa, 18 (62%) showed high-grade atypia, most of them metastatic colon cancer
  • Moderate to strong p53 staining was present in 8 of the 18 high-grade metastases to the tubal mucosa
  • The remaining 11 tumors with mucosal growth had bland nuclei or minimal atypia
  • Among the 85 patients with follow-up, median survival was 24.3 months from the fallopian tube surgery
• The authors' conclusion: The authors concluded that, by routine light microscopy, tumor cells growing within the fallopian tube mucosa are not indisputable evidence that the tumor originated from the tubal mucosa

Topics

Medical terms in this study, explained in our Lexicon: Carcinoma, Epithelium, Adenocarcinoma, Mesothelioma, Metastasis, Cytology.

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