Oncocytic, focally anaplastic, thyroid cancer responding to erlotinib

OBJECTIVE: To highlight the molecular findings and clinical response of a patient with rapidly progressing, focally anaplastic, oncocytic thyroid carcinoma (OTC) treated with erlotinib.Case Summary. A 69-year-old woman with recurrent, focally anaplastic OTC was given a therapeutic trial of erlotinib, a small molecule inhibitor of epidermal growth factor receptor (EGFR). Formalin-fixed, paraffin-embedded portions of the tumor were analyzed for EGFR expression, and tumor genomic DNA was amplified by polymerase chain reaction (PCR) and subjected to EGFR mutation analysis.Discussion. An early and dramatic response was achieved with erlotinib. The tumor was focally positive for EGFR by immunostaining and two point mutations were identified, one on exon 18 and one on exon 20 in the tyrosine kinase (TK) domain. CONCLUSION: Erlotinib or other novel protein kinase pathway inhibitors should be evaluated further in patients with aggressive thyroid cancer variants, who may exhibit these and perhaps other tyrosine kinase mutations.