EMERGENCEOF IDIOPATHIC MAST CELL ACTIVATION SYNDROME STATUS POSY HYSTERECTOMY IN A 44 Y.O. CAUCASIAN WOMAN
Mast cell disorders may be attributed to neoplastic proliferation such as mastocytosis or inappropriate activation of mast cells known as Mast Cell Activation Syndrome (MCAS) as defined in 2010 proposed diagnostic criteria. MCAS is a multisystem disease with variable presentations, making diagnosis elusive and often delayed.
A 44-year-old Caucasian woman with history of hypothyroidism developed MCAS following hysterectomy for menometorrhagia. Before hysterectomy, patient experienced occasional hives and diarrhea. A few months after surgery, patient developed sudden reaction to food and medications, frequent urticarial reactions and flushing, mental fogginess, neck angioedema, bronchoconstriction with wheezing, and anal and bladder sphincter spasms. While patient manifested symptoms of mast cell disorder, her tryptase level was normal at 3.8 ng/mL. 24-hour urine Leukotriene E4 and 2,3-dinor 11B-Prostaglandin F2a were both normal at <51 pg/mg Cr and 2839 pg/mg Cr respectively, adding to difficulty of diagnosis. Further testing revealed elevated 24-hour urine N-methylhistamine at 224 mcg/g Cr. Bone marrow biopsy and peripheral blood flow cytometry including genetic analysis for Jak2, c-KIT, FIP1L1, and PDGFRA mutations were normal. Patient’s final diagnosis was idiopathic MCAS.
MCAS is a heterogeneous disease associated with increased risk of anaphylaxis. Treatment includes H1 and H2 antihistamines, mast cell stabilizers, leukotriene inhibitors, and occasionally prednisone. Although the patient did not tolerate cromolyn, she has tried H1/H2 antihistamines with some relief. She is currently trying imatinib. Self-injectable epinephrine and anaphylaxis education should be provided to MCAS patients. High index of suspicion is important for timely diagnosis and treatment that significantly improves quality of life.