Endometriosis‐related pathology: a discussion of selected uncommon benign, premalignant and malignant lesions

Abstract

Endometriosis is an extremely common condition and, in most cases, establishing a histological diagnosis is straightforward, although a variety of benign alterations may result in problems with interpretation. In this review, I discuss selected uncommon variants of endometriosis or benign alterations that may result in diagnostic problems. The topics covered include the contentious issue of so‐called atypical endometriosis, stromal endometriosis, polypoid endometriosis, and the association of endometriosis with florid mesothelial hyperplasia. The propensity of endometriosis to undergo neoplastic transformation (especially to endometrioid and clear cell carcinoma) is well known. Selected issues relating to the various neoplasms that can arise in endometriosis are discussed, with a particular concentration on unusual variants of endometrioid carcinoma that result in a disproportionately high number of issues in referral practice. The propensity of ovarian endometrioid carcinomas to show an unexpected (‘aberrant’) immunophenotype with positive staining with ‘intestinal’ markers and negative staining with Mullerian markers is also discussed. Uncommon tumour types that may arise in endometriosis, namely seromucinous neoplasms, mesonephric‐like carcinomas, and somatically derived yolk sac tumours, are also covered.

Atypical endometriosis is related to a higher recurrence rate

“…The definition of atypical endometriosis included cytologic atypia, architectural atypia, or hyperplasia. According to McCluggage, reactive change of ovarian endometrioma can occur secondary to repeated episodes of hemorrhage and may be confused with atypical endometriosis [10]. Therefore, we excluded those patients who were also diagnosed with cytological atypia or hyperplasia associated with reactive change (n = 30).…”

Endometriosis-Associated Ovarian Cancer: The Origin and Targeted Therapy

“…Nuclear atypia with no proliferative features, which are often seen, is considered to be a reactive change. A proliferative lesion similar to a precancerous lesion of endometrioid carcinoma of the endometrium is considered to be a true precancerous lesion, but this is rarely observed [ 34 ].…”

Ileal obstruction caused by transmural endometriosis in a patient with simultaneous C. difficile colitis and Influenza AH1N1. Case report

“…This process has multiple interconnected factors both inherited and acquired [ 4 ]. The most common locations are ovaries, fallopian tubes, pouch of Douglas, and pelvic peritoneum [ 5 ]. The common clinical manifestations are dysmenorrhea, chronic pelvic pain, dyspareunia, and infertility [ 5 ].…”

“…Differential diagnoses of luminal stenosis are tuberculosis, Crohn’s disease, adenocarcinoma, lymphoma, gastrointestinal stromal tumor, and carcinoid tumor [ 2 , 12 ]. Histological diagnosis is straightforward by identification of endometriotic foci [ 5 ]. Diagnostic triad refers to endometrioid-type glands, endometrioid-type stroma, and hemosiderin-laden macrophages [ 9 ].…”