A 70-year-old Filipino woman presented with vague symptoms not usual for systemic mastocytosis (SM), including atypical skin lesions, but a full workup revealed that she had the disease, and she eventually responded to treatment, according to a case report presented at the 12th annual meeting of the Society of Hematologic Oncology in September in Houston.
The case suggests that clinicians consider an appropriate workup to screen for SM and prompt treatment in such patients if they have reason to suspect SM may exist, especially since SM may be indolent on occasion but may transform to a more aggressive type of the disease with an elevated risk for morbidity and mortality.
“Delay in diagnosis [of SM can impair] quality of life and may lead to life-threatening consequences,” the study said.
What is SM?
Systemic mastocytosis (SM) is a rare hematological disease characterized by mast cells—specialized cells of the immune system that mediate inflammatory responses and allergic reactions—that are overactive and accumulate in different parts of the body such as the bone marrow, liver, spleen, gastrointestinal tract and lymph nodes.
The case study subject had no history of any allergies and presented with a flat, itchy rash on her extremities, trunk and face but not on her scalp, palms or the soles of her feet. She had lost considerable weight, had blood in her stool and reported recurring pain in her upper abdomen. A workup revealed anemia, low platelet count and elevated eosinophil count (a type of white blood cell).
The patient underwent bone marrow and colon biopsies, which revealed the presence of eosinophilia, or elevated levels of eosinophils, along with mast cell infiltration that was positive for CD117/CD25 and negative for platelet-derived growth factor receptor, indicators of SM.
She was given a course of imatinib to treat advanced SM accompanied by gastrointestinal, bone marrow and skin involvement. Her physicians may consider stem cell transplantation in the course of her disease. She is currently receiving regular monitoring and follow-up in an outpatient setting.
SM is associated with the accumulation of abnormal mast cells in various tissues and organs of the body, driven mainly by mutations in the KIT gene. Mast cell activation plays a key role in disease progression, particularly among individuals with cutaneous manifestations.
To date, there are limited data on the prevalence and incidence of cutaneous mastocytosis and SM or any strong gender predominance.
Individuals with more aggressive forms of the disorder may experience vague GI symptoms, hematologic findings, osteoporosis and unexplained splenomegaly or lymphadenopathy.
