Atypical Polypoid Adenomyofibromas (Atypical Polypoid Adenomyomas) of the Uterus

Abstract

We present the clinicopathological and immunohistochemical features of 55 atypical polypoid adenomyofibromas, a definitional expansion of an entity previously reported as "atypical polypoid adenomyoma" (APA) of the uterus. Patients ranged in age from 25 to 73 (mean, 39.9) years. All but two of the patients were premenopausal, and 14 were undergoing evaluation for infertility. Histologically, the lesions featured a biphasic proliferation of architecturally complex and cytologically atypical endometrial glands within a myofibromatous stroma. The histologic pattern ranged from widely separated and loosely clustered irregular but branched glands embedded in broad zones of cellular myofibromatous stroma to those possessing crowded, markedly complex, branching glands separated by sparse intersecting fascicles of fibromuscular tissue. The stroma in all cases was actin or desmin positive or both. Morular/squamous metaplasia was present in all but two cases and florid in most. All cases exhibited architecturally complex glands, and in 25 cases the architectural complexity was indistinguishable from that of well-differentiated endometrial adenocarcinoma, as we have defined it; that is, they had a high architectural index. Twenty-nine patients were initially treated with polypectomy or curettage followed by hormonal therapy; persistent or recurrent APA developed in 45% of the patients in this group (33% with low architectural index vs. 60% with high architectural index). Five patients had successful pregnancies despite persistent disease. Superficial myoinvasion was identified in the hysterectomy specimen in two of 12 APAs with a high architectural index but not in 21 APAs with a low architectural index. All patients are alive and well 1 to 112 months after diagnosis (mean, 25.2 months). On the basis of this study, we propose that APAs with markedly complex glands (high architectural index) be designated "atypical polypoid adenomyofibromas of low malignant potential" (APA-LMP) to emphasize the potential risk for myometrial invasion. A treatment program featuring local excision accompanied by close follow-up is warranted for APA despite the presence of recurrent or persistent disease. Patients with APA-LMP may also, in selected cases, be managed with less than hysterectomy, although (as with the usual well-differentiated carcinoma) there is a small but definite risk associated with this approach.

A practical approach to the diagnosis of mixed epithelial and mesenchymal tumours of the uterus

“…50,[60][61][62] Most patients are premenopausal or perimenopausal (average age 40 years) and present with abnormal uterine bleeding, usually menorrhagia. Rare examples have been described in patients with Turners syndrome who have been prescribed unopposed oestrogens.…”

“…Significant glandular crowding may occur and may be indistinguishable from a grade I endometrioid adenocarcinoma. The term atypical polypoid adenomyoma of low malignant potential has been suggested for lesions with marked architectural complexity, 61 but this term is not in widespread use and is not recommended. However, in such cases, if the tumour is not completely excised, then the risk of recurrence is higher.…”

Problems in the Differential Diagnosis of Endometrial Hyperplasia and Carcinoma

“…An additional entity unique to the differential diagnosis of complex and atypical complex hyperplasia is the atypical polypoid adenomyoma or, as it has been called more recently, atypical polypoid adenomyofibroma (23). This lesion is observed predominantly in premenopausal and perimenopausal women and develops as a solitary polypoid lesion, most commonly in the lower uterine segment and endocervix.…”

Smooth Muscle, Endometrial Stromal, and Mixed Müllerian Tumors of the Uterus

“…Although the mesenchymal component of APA is usually smooth muscle, it is our experience that many lesions have a hybrid fibrous and smooth muscle stroma (30). Morular metaplasia is present is more than 90% of the cases and is a useful marker of this lesion (Fig.…”

“…On occasion, the glands in otherwise characteristic APA have the architectural features of well-differentiated adenocarcinoma. Such lesions can extend into the myometrium, and we label them as APA of low malignant potential (30,31). Another characteristic feature of all APAs is the patient's age, which generally ranges from 35 to 45.…”