Background: The Tall cell variant of papillary carcinoma of the thyroid (TCV) is characterized by the proliferation of oxyphilic, tall, columnar cells with a height-to-width ratio of at least 2:1. TCV exhibits more aggressive clinical behavior than conventional thyroid papillary carcinoma (CPC). Cytologic features suggestive of TCV have been described in fine-needle aspiration material from primary tumors. Similarly, loss of heterozygosity (LOH) for chromosome 1 (D1S243) and the p53 gene (TP53) have been reported in TCV but not in CPC, thus making exploitation of this genetic feature a potential tool for molecular discrimination between these two neoplasms.
Methods: Cytology samples of metastatic and/or recurrent neoplasms (M/R) (12 cases) and 7 cases of primary TCV obtained from 12 patients were evaluated. The cytologic findings of these cases were compared with previously published findings. Microdissection and polymerase chain reaction for LOH for chromosome 1 and p53 (D1S243 and TP53 markers) were performed on cytologic smears from 6 cases of M/R tumors and 3 cases of primary tumors.
Results: More then 50% of M/R showed atypical follicular cells with enlarged nuclei, granular chromatin, nuclear grooves, pseudoinclusions, and abundant finely granular cytoplasm. Cells were disposed in monolayers (58%) and papillary clusters (50%). Similar findings were present in cases of primary TCV. LOH studies showed that 4 of 6 M/R were noninformative and 2 of 3 cases of primary TCV were informative for the D1S243 marker; however, in contrast with previously published reports, no LOH was detected for the markers evaluated.
Conclusions: M/R and primary TCV have similar cytologic features. Additional studies of larger series of M/R and primary TCV should be performed to delineate further any potential application of LOH for chromosome 1 and the p53 gene as a tool for diagnosing TCV with cytologic preparations. Cancer (Cancer Cytopathol)
Copyright 1999 American Cancer Society.