Papillary carcinoma with nodular fasciitis-like stroma--a case report in pregnancy.

We report a case of Papillary carcinoma with nodular fasciitis-like stroma that is a rare variant of Papillary carcinoma characterized by a prominent stromal cell proliferation that causes difficulties in cytologic and histologic diagnosis. The patient was a 34-year-old woman, pregnant, presented with a 1-year history of a growing mass in neck, dysphagia, and hoarseness. Physical examination revealed a firm nodular mass in thyroid gland. The fine needle aspiration biopsy specimen contained, besides diagnostic epithelial features of Papillary thyroid carcinoma, discohesive arrangement of bland spindle cells. Macroscopically, the specimen consisted of nodular tumor measuring 10 x 6 x 6 cm. Histologically the tumor was composed of small foci of neoplastic epithelial component distributed in abundant stroma. In immunohistochemistry, spindle cells in the stroma were positive for alpha-smooth muscle actin and the neoplastic cells showed positive staining for TTF-1 and progesterone receptor.