Papillary carcinoma of the thyroid with fibromatosislike stroma: case report and review of literature.

Objective: To describe a case of papillary carcinoma of the thyroid with fibromatosislike stroma, emphasize the need for a diligent search for papillary thyroid cancer in the presence of a fibroproliferative lesion, highlight the peculiar hormonal response of the stromal component, and review the pertinent literature.
Methods: We present the clinical, laboratory, radiologic, and pathologic findings in a patient with papillary carcinoma of the thyroid with fibromatosislike stroma and review the related published material.
Results: A 29-year-old woman presented to our surgical department because of a large mediastinal mass. She underwent surgical removal of the mass by means of a median sternotomy and neck extension. Pathology examination revealed macroscopically tan scarlike tissue, which by histologic study consisted of a dominant fibroproliferative lesion overshadowing a minor component of papillary carcinoma of the thyroid. Further neck exploration with total thyroidectomy revealed multifocal papillary carcinoma of the thyroid. Postoperatively, the patient received radioiodine treatment. A local and aggressive recurrent tumor was observed during a subsequent pregnancy; the lesion was not amenable to complete resection but fascinatingly responded to antiestrogen therapy (orally administered tamoxifen).
Conclusion: The presence of a fibroproliferative lesion could be misleading. A diligent search should be made for a papillary thyroid carcinoma component within fibromatosislike stroma. The mode of manifestation of the tumor and its response to hormonal manipulation are distinctive features of this case.