Systemic Mastocytosis with associated CMML

• Main Authors: Tawadros, Fady, Chakraborty, Kanishka
• Format: Others
• Published: Digital Commons @ East Tennessee State University 2018
• Subjects: Systemic mastocytosis; chronic myelomonocytic leukemia; malignant hematology; Hematology; Oncology
• Online Access: https://dc.etsu.edu/asrf/2018/schedule/75

Systemic mastocytosis refers to a heterogeneous group of clinical disorders characterized by excessive mast cell accumulation in one or multiple organs. Mastocytosis is now considered as a separate disease category in the 2016 WHO classification of myeloid neoplasm and acute leukemia. It is no longer considered as a subgroup of meyloproliferate neoplasms. The clinical presentation of mastocytosis is heterogeneous ranging from skin-limited disease (cutaneous mastocytosis) to a more aggressive form with extra cutaneous presentation (systemic mastocytosis) with or without skin involvement. We are presenting a case of systemic mastocytosis that aroused in a patient who carried diagnosis of CMML for almost 2 years. The worsening B symptoms along with worsening splenomegaly were the driving factor for further investigations including Bone Marrow biopsy which revealed the diagnosis. A 74 year old Caucasian male with past oncology history of Chronic myelomoncytic leukemia diagnosed after persistant monocytosis on complete blood count . Patient presented with gradual onset of low grade fever , weight loss and night sweating , CT abdomen showed hepatosplenomegaly. core biopsy of the liver showed portal and lobular infiltrate consistent with involvement by mastocytes and extra medullary hematopoiesis. The infiltrate was positive for CD117, CD33, CD68, myeloperoxidase and CD163. Patient had bone marrow biopsy which showed increased CD117 positive cells consistent with involvement by systemic mastocytosis. The core biopsy showed multifocal nodules of spindle cells with fibrosis which was morphologically consistent with abnormal mast cells. Immunohistochemistry for CD117 was strongly positive in the spindle cell nodules and scattered polygonal cell nodules. KIT D816V mutation was detected. Patient met criteria for diagnosis of systemic mastocytosis with presence of previous diagnosis of CMML and classified as Systemic mastocytosis with an associated hematologic neoplasm (SM-AHN). Due to patient multiple comorbiditeis , he was not a candidate for Allo HCT. In an attempt to control his disease , patient was started on dose reduced Dacogen, but his functional status continued to delined and eventually dacogen was discontinued and patient was placed on best supportive car Conclusion Systemic mastocytosis is a rare entity with heterogeneous clinical presentation, highly variable disease course and consequently survival rates.Though recent advances in understanding genetic and molecular basis of disease, bone marrow transplantation remains the only treatment with possible curative potential in patients with advanced form of mastocytosis though carrying substantial mortality risk .Further understanding of Kit mutation might be able to offer a highly effective medication with durable response in a fashion similar to the success story of gleevac with CML treatment .