Mast Cell Sarcoma

MAST CELL SARCOMA^{1, 2}

Mast cell sarcoma is a rare tumor that may present in many different anatomic locations and age groups, and prognosis is generally poor. Mast cell sarcoma is often misdiagnosed because the presenting cells bear little resemblance to normal mast cells and spindle-shaped mast cells frequently seen in systemic mastocytosis.³ The cells of mast cell sarcoma more closely resemble “atypical type II mast cells” or “promastocytes” that are associated with some cases of aggressive systemic mastocytosis.^{1, 3} Pathological examination of the tumor has shown it to be highly malignant with an aggressive growth pattern.^{3, 4} Patients with this tumor do not fulfill the criteria for SM.¹ The imatinib mesylate-resistant KIT D816V mutation has not been found in reported mast cell sarcomas, such that use of imatinib has been attempted in some patients.³