VGLL3-Rearranged Spindle Cell Rhabdomyoblastic Tumor: A Clinicopathologic and Molecular Genetic Study of 18 Cases With Consistently Indolent Behavior.

We report 18 cases with extended clinical follow-up, detailed molecular results, and methylation profiling.

Tumors occurred in 5 females, 12 males, and 1 patient of unknown sex with a median age of 58 years (range, 22-71).

Tumors involved the tongue (n = 13), lower lip (2), retropharyngeal region (n = 1), thyroid/parathyroid (n = 1), and palatine tonsil (1), with a median size of 1.2 cm.

Necrosis was consistently absent with a median mitotic rate of 1/10 high-power fields (range, 0-7/10).