The tall cell variant of papillary carcinoma of the thyroid - Cytologic features and loss of heterozygosity of metastatic and/or recurrent neoplasms and primary neoplasms

BACKGROUND. The Tall cell variant of papillary carcinoma of the thyroid (TC V) 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). Cyt ologic features suggestive of TCV have been described in fine-needle aspira tion 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 potenti al tool for molecular discrimination between these two neoplasms. METHODS. Cytology samples of metastatic and/or recurrent neoplasms (M/R) (1 2 cases) and 7 cases of primary TCV obtained from 12 patients were evaluate d. The cytologic findings of these cases were compared with previously publ ished findings. Microdissection and polymerase chain reaction for LOH for c hromosome 1 and p53 (D1S243 and TP53 markers) were performed on cytologic s mears from 6 cases of MIR tumors and 3 cases of primary tumors. RESULTS. More then 50% of M/R showed atypical follicular cells with enlarge d nuclei, granular chromatin, nuclear grooves, pseudoinclusions, and abunda nt finely granular cytoplasm. Cells were disposed in monolayers (58%) and p apillary 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 case s of primary TCV were informative for the D1S243 marker; however, in contra st with previously published reports, no LOH was detected for the markers e valuated. CONCLUSIONS. MIR and primary TCV have similar cytologic features. Additiona l studies of larger series of M/R and primary TCV should be performed to de lineate further any potential application of LOH for chromosome 1 and the p 53 gene as a tool for diagnosing TCV with cytologic preparations. (C) 1999 American Cancer Society.