BackgroundOvarian fibromas are benign tumors that can present peculiar morphological features not studied sufficiently. Material and MethodsIn this retrospective study, 75 consecutive cases of ovarian fibroma were morphologically compared with 46 thecomas, 16 granulosa cell tumors, and 5 sclerosing stroma tumors for the following factors: the growth pattern as diffuse or nodular, the presence of hyaline plaques, necrosis, keloid-like sclerosis, calcifications, cystic degeneration, fibrous or edematous stroma, prominent vascularity, lutein cells, cellularity, scant or abundant cytoplasm, prominent cell membranes, nuclear grooves, atypia, and mitotic activity. ResultsThe tumors differed significantly in terms of hyaline plaques presence, nuclear grooves, growth pattern, stroma type, tumor cellularity, cytoplasm, prominence of cell membranes, atypia, mitotic activity, and prominent vascularity. ConclusionOvarian fibromas can present some maybe unexpected features rather frequently, such as cystic degeneration, hyaline plaques, prominent vascularity, increased cellularity, and some mitotic activity, thus their presence should not always prompt to an alternative diagnosis.