Myxoid change in decidualized scar endometriosis mimicking malignancy

Abstract

A case of cesarean scar endometriosis with massive decidualization is presented. The 25-year-old patient had an extensive, ulcerated lesion that mimicked malignancy microscopically due to myxoid change with alveolar patterns reminiscent of some soft tissue sarcomas, signet ring-like cells similar to mucin-producing carcinoma, and pseudoinfiltration of the fascia. The myxoid tissue was positive for acid mucopolysaccharides but negative with PAS. Decidual cells were vimentin positive and keratin negative. No atypia or mitoses were seen. The pseudoinfiltrative aspect was due to abundant extracellular matrix that separated the fascicles of the fascial tissue. There was a metaplastic decidual "proximity effect" in the surrounding, unaffected dermis, which may be responsible for the expansile features of the lesion. This case exemplifies the differential diagnosis of myxoid endometriosis with malignant conditions of the skin.

Morphological variations of scar-related and spontaneous endometriosis of the skin and superficial soft tissue: A study of 71 cases with emphasis on atypical features and types of müllerian differentiations

“…[25][26][27][28] Its incidence in the Steck and Helwig series 2 was 9 of 82, while we have observed only one case among our 71 patients. Decidualized endometrium is due to the influence of ovarian and placental hormones, principally progesterone; thus it is commonly encountered in histologic specimens obtained during pregnancy or progestin therapy.…”

Cutaneous Decidualized Endometriosis in a Nonpregnant Female

“…Cutaneous endometriomas with atypical features, including decidualization, may also mimic malignancy. 12,13 Furthermore, malignant transformation of cutaneous endometriomas has rarely occurred. 14-16 Therefore, heightened awareness of the changes that can occur in cutaneous endometriosis is essential.…”

Histological features in abdominal wall endometriosis

“…Decidual changes in our study were seen in 1 case. When it is diffuse, it needs to be separated from the malignancy [16]. For this reason, additional immunohistochemical staining may be required [2].…”

“…The diagnosis could be confirmed by detecting nuclear positive ER and PR markers in desidual cells. Decidual changes usually occur in the presence of pregnancy [14,16]. However, such changes have been reported in patients who have not had previous pregnancy stories [15].…”

“…With the increase in the number of cases of AWE in recent years, it is necessary to keep in mind the histological changes in these cases in terms of the differentiation from malignancies [15][16][17].…”