• Recently described rare variant of Papillary thyroid carcinoma (PTC) with aggressive behavior (extrathyroidal extension, nodal and distant metastasis) and relatively poor prognosis (lower long term survival).
• Microscopically, it is characterized by micropapillary growth pattern and Hobnail appearance of cells.
• The Diagnosis of PTC hobnail variant requires at least 30% of hobnail-micropapillary pattern in the tumor.
• Its a Rare tumor, < 1% of all PTC
• It is placed between well differentiated classic PTC and poorly differentiated thyroid cancer.
• The BRAF mutation is a likely driver, followed by second hits in TP53, TERT promoter, PIK3CA or CTNNB1
• Hobnail PTC itself indicates propensity for higher grade transformation
• The local recurrence rate is 23%, lymph node metastasis 60% – 75%, distant metastasis 25% – 40%

Hobnail Papillary PTC Thyroid

Last modified: 11/07/2021