Glomus tumors are rare mesenchymal neoplasms with a phenotype akin to the modified smooth muscle cells of the glomus body. Most are benign, but rare examples show malignant histologic characteristics and aggressive behavior. In Aug 22, 2017, Karamzadeh Dashti N and others published an article in << The American Journal of Surgical Pathology >> which title is“BRAF V600E Mutations Occur in a Subset of Glomus Tumors, and are Associated With Malignant Histologic Characteristics”. They recently encountered a malignant glomus tumor with BRAF V600E mutation. They sought to study a large cohort for this mutation, with particular attention to associated malignant histologic characteristics. Three of 11 malignant tumors (27%) had progressive disease: 1 with metastasis to brain and heart, 1 with enlarging residual disease, and 1 with recurrence. Two of 4 GT-UMP (50%) had progressive disease: 1 with metastasis to lung, and 1 with local recurrence (50%). Three of 44 benign tumors (7%) had local recurrence. Two of 5 patients with BRAF V600E had progression, including 1 GT-UMP with local recurrence and 1 malignant tumor with enlarging residual disease. In summary, BRAF V600E mutation was detected in 6% of glomus tumors, all of which were malignant or GT-UMP. This mutation may be associated with a malignant phenotype, although study of additional cases is needed. In patients with progressive disease, BRAF could be a promising therapeutic target.
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