title: Thyroid carcinoma with papillary and squamous features: report of a case with histogenetic considerations.
abstract: We present a case of an 82-year-old female with a painless left latero-cervical swelling, which increased in size over the course of 6 months, compressing adjacent organs. The histopathological examination, following dissection of the left thyroid lobe and ipsilateral cervical lymph nodes, yielded two intermingled morphologically distinct histotypes that included conventional papillary thyroid carcinoma (PTC) and poorly differentiated squamous cell carcinoma (SCC) with cystic features. The clinical presentation, the immunophenotype, and the genotype, especially of the malignant squamous component with partial expression of TTF1, marked expression of p63 and mutation of BRAF, were consistent with the diagnosis of a papillary thyroid carcinoma with squamous component. The possibility of a squamous cell carcinoma of unknown origin metastasizing to a primary papillary thyroid carcinoma cannot be completely ruled out. This particular presentation of thyroid carcinoma carries a poor prognosis in 20% of cases, with high recurrence rates and distant metastasis.
authors.affiliation: Institute of Pathology CHUV and University of Lausanne, CH-1011 Lausanne, Switzerland.
authors.forename: Th
authors.initials: T
authors.lastname: Rausch
authors.forename: J
authors.initials: J
authors.lastname: Benhattar
authors.forename: M
authors.initials: M
authors.lastname: Sutter
authors.forename: S
authors.initials: S
authors.lastname: Andrejevic-Blant
mesh_terms: D000369:Aged, 80 and over; D002291:Carcinoma, Papillary / Q000235:genetics / Q000473:pathology* / Q000601:surgery; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000473:pathology* / Q000601:surgery; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D018198:Mixed Tumor, Malignant / Q000235:genetics / Q000473:pathology* / Q000601:surgery; D009154:Mutation / Q000235:genetics; D011379:Prognosis; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics; D013964:Thyroid Neoplasms / Q000235:genetics / Q000473:pathology* / Q000601:surgery
chemical_list: C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf