title: Papillary thyroid carcinoma with predominant spindle cell component: report of two rare cases and discussion on the differential diagnosis with other spindled thyroid neoplasm.
abstract: Spindle cell transformation or metaplasia has been so far demonstrated in the context of both benign and malignant conditions. Spindle cell lesions of the thyroid gland of either primary or secondary origin to metastatic disease represent rare entities. We describe two patients with papillary thyroid carcinoma (PTC) showing spindle cell metaplasia, submitted to thyroidectomy due to euthyroid bilateral nodular thyroid disease. Cytological examination of fine-needle aspiration biopsy performed in the dominant nodules was consistent with follicular neoplasm in one case and with a hyperplastic/adenomatous nodule in the other patient. Histological examination disclosed unencapsulated follicular variant of PTC with spindle cell metaplasia in either cases. Both patients are doing well without clinical or laboratory evidence of PTC recurrence at 3- and 1-year follow-up, respectively. We present the clinical, pathological, and immunohistochemical aspects of these unusual cases and thoroughly discuss the differential diagnosis with other spindle cell lesions of the thyroid gland.
authors.affiliation: Institute of Pathology, University of Modena and Reggio Emilia, Modena, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Corrado
authors.forename: Salvatore Maria
authors.initials: SM
authors.lastname: Corsello
authors.forename: Antonio
authors.initials: A
authors.lastname: Maiorana
authors.forename: Esther Diana
authors.initials: ED
authors.lastname: Rossi
authors.forename: Alfredo
authors.initials: A
authors.lastname: Pontecorvi
authors.forename: Guido
authors.initials: G
authors.lastname: Fadda
authors.forename: Giampaolo
authors.initials: G
authors.lastname: Papi
mesh_terms: D002291:Carcinoma, Papillary / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008679:Metaplasia / Q000473:pathology; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D013961:Thyroid Gland / Q000473:pathology*; D013964:Thyroid Neoplasms / Q000473:pathology*