Hürthle cell (oxyphilic) papillary thyroid carcinoma: a variant with more aggressive biologic behavior

Area of Science:

• Endocrinology
• Oncology
• Pathology

Background:

• The World Health Organization (WHO) International Classification defines papillary thyroid carcinoma by specific cellular and nuclear features.
• Oxyphilic (Hürthle cell) papillary carcinomas present with nuclei resembling those in oxyphilic follicular carcinomas.
• These oxyphilic variants may exhibit more aggressive clinical behavior compared to typical papillary thyroid cancers.

Purpose of the Study:

• To further characterize the rare oxyphilic papillary thyroid carcinoma.
• To compare the clinical and pathological features of oxyphilic papillary cancer with typical papillary cancer and oxyphilic follicular cancer.

Main Methods:

• Retrospective analysis of 22 patients with oxyphilic papillary cancer treated over 32 years.
• Comparison with 1,084 patients with typical papillary cancers and 57 patients with oxyphilic follicular cancers.
• Evaluation of clinicopathological parameters including age, tumor size, TNM stage, AGES score, nodal metastases, DNA ploidy, tumor recurrence, and cause-specific mortality.

Main Results:

• Oxyphilic papillary cancers showed fewer neck nodal metastases (5% vs 40%) and higher rates of DNA non-diploidy (71% vs 21%) compared to typical papillary cancers.
• After 10 years, oxyphilic papillary cancers had significantly higher tumor recurrence (28% vs 11%) and cause-specific mortality (4% vs 1.7%).
• These features more closely resembled those of oxyphilic follicular cancers.

Conclusions:

• Oxyphilic papillary thyroid cancers exhibit distinct clinicopathological characteristics compared to typical papillary thyroid cancers.
• The aggressive behavior and molecular features of oxyphilic papillary cancers align more closely with oxyphilic follicular cancers.
• These findings suggest a unique biological profile for oxyphilic papillary thyroid carcinoma.