SEER is an authoritative source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 28 percent of the U.S. population.
9 - Grade/differentiation unknown, not stated, or not applicable
M3 Module 5: PH9
Malignant mast cell tumor
An exceedingly rare entity characterized by localized but destructive growth of a tumor consisting of highly atypical, immature mast cells. Although initially localized, distant spread is seen after a short interval. The cells may resemble those of Mast cell leukemia (9742/3), and a leukemic phase may occur. Reported to occur in the larynx, large bowel, meninges, bone and skin.
Extremely rare neoplasm characterized by a localized and destructive growth of highly atypical mast cells which can be identified only with the application of appropriate immunohistochemical markers. Mast cell sarcoma is initially localized, followed within months by distant spread and terminal phase.
Definitive Diagnostic Methods
Somatic point mutation at codon 816 in KIT receptor gene (most common mutation is D816V)
Immunohistochemical markers anti-tryptase/chymase and anti-CD117