title: Endometrial Endometrioid Carcinoma With Large Cystic Growth Configuration and Deceptive Pattern of Invasion Associated With Abundant Nodular Fasciitis-like Stroma: A Unique Hitherto Unreported Histology in Endometrioid Carcinoma.
abstract: We describe a case of an unusual endometrial endometrioid carcinoma occurring in a 67-year-old woman. The tumor involved uterine corpus as well as lower uterine segment and presented as polypoid tumor protruding through the cervical orifice. Microscopically, the tumor was characterized by broad zones of cytologically bland fibromyxoid stroma resembling nodular fasciitis, showing vaguely nodular architecture. Neoplastic glands were characterized by interconnected elongated slit-like and large cystic profiles, mostly lined by flattened epithelium with variable squamous differentiation, whereas typical columnar endometrioid cells were only focally present. Voluminous nodules of the stroma produced phyllodes-like appearance of the tumor. The tumor showed some resemblance to the microcystic, elongated, and fragmented (MELF) glands growth pattern, but in contrast with MELF pattern, where fibromyxoid change occurs focally, in the presented case abundant myofibroblastic proliferation was present throughout the tumor and the neoplastic glands showed anastomosing "large cystic" rather than "small cystic" profiles. Some of the neoplastic glands presented almost complete or complete squamous differentiation, with relatively bland-looking squamous cells and no hint of endometrioid differentiation, which resulted in initial misdiagnosis of Müllerian adenofibroma. We believe that nodular fasciitis-like pattern represents yet undescribed, and diagnostically challenging pattern of invasion in endometrial endometrioid carcinoma.
authors.affiliation: *Šikl's Department of Pathology, The Faculty of Medicine and Faculty Hospital in Pilsen, Charles University, Prague †Bioptická laboratoř, s.r.o., Pilsen, Czech Republic ‡Department of Radiation Oncology, Oncology Institute §Department of Pathology, Louis Pasteur University Hospital, Košice, Slovakia.
authors.forename: Marián
authors.initials: M
authors.lastname: Švajdler
authors.forename: Michael
authors.initials: M
authors.lastname: Michal
authors.forename: Pavol
authors.initials: P
authors.lastname: Dubinský
authors.forename: Peter
authors.initials: P
authors.lastname: Švajdler
authors.forename: Ondrej
authors.initials: O
authors.lastname: Ondič
authors.forename: Michal
authors.initials: M
authors.lastname: Michal
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D018269:Carcinoma, Endometrioid / Q000473:pathology*; D003560:Cysts / Q000473:pathology; D016889:Endometrial Neoplasms / Q000473:pathology*; D005208:Fasciitis / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry
chemical_list: D014408:Biomarkers, Tumor