Extensive morular metaplasia in an endometrial polyp – A rare occurrence - creating a diagnostic dilemma

Abstract

Morular metaplasia is an unusual type of metaplastic change, often observed in numerous endometrial lesions. It has been considered a variant of squamous metaplasia and has a mulberry-like appearance. Morular metaplasia lacks the characteristic histopathological features of conventional squamous differentiation and hence their relationship with each other has not been clearly defined. These lesions are usually seen along with pre-malignant and malignant glandular lesions of endometrium. Their presence in normal endometrium or benign endometrial polyps is rare, however it can cause a diagnostic dilemma. We present a case of a 39-year-old female who underwent hysteroscopic removal of an endometrial polyp. On gross examination it was a well-defined tan white lesion. Microscopy showed cystically dilated glands along with foci of extensive morular metaplasia. There was no evidence of any atypia/ dysplasia or malignancy in the material studied. It is important to report morular metaplasia in benign localised endometrial lesions due its usual association with endometrial hyperplasia/ atypical hyperplasia or endometrial endometrioid carcinoma. The patient requires regular follow up with clinico-radiological correlation in view of risk of presence of other coexisting lesions in these cases.