Idiopathic mast cell activation syndrome and radiation therapy: a case study, literature review, and discussion of mast cell disorders and radiotherapy.

BACKGROUND: Mast Cell Activation Syndrome (MCAS) is classified as an idiopathic mast cell disorder where inconsistent or unknown triggers release inflammatory mediators and cause a constellation of symptoms. Studies demonstrate mast cells increase histamine, tryptase, and inflammatory cytokine expression following ionizing radiation. Additionally, there are cases of cutaneous mastocytosis developing within the initial radiation field suggesting mast cells play a role in local tissue reactions. Literature is sparse on radiation induced toxicity in patients with mast cell disorders. CASE PRESENTATION: A 62 year old female patient with a history of MCAS received breast conservation therapy for invasive lobular carcinoma of the left breast initially AJCC 7th Stage IIB, pT3 pN0 M0. The patient underwent external beam radiotherapy (EBRT) and received 4500 cGy to the left whole breast, followed by a 1000 cGy boost to the lumpectomy cavity. She developed grade 1 radiation dermatitis. Two years later she progressed distantly and received stereotactic body radiation therapy to a lumbar vertebrae lesion to a dose of 2400 cGy in a single fraction. She developed no in-field dermatologic or systemic flare in her MCAS symptoms during radiation therapy. CONCLUSIONS: To our knowledge there are no reported cases in the literature of patients diagnosed with MCAS or other idiopathic mast cell disorders undergoing radiation therapy. Idiopathic mast cell disorders such as MCAS and primary mast cell disorders alike should not be considered a contraindication to treatment with EBRT. This patient population appears to tolerate treatment without systemic flares in symptoms.

Radiation therapy in a case of systemic mastocytosis: evaluation of histamine levels and mucosal effects.

Plasma histamine levels were obtained during palliative radiation therapy of the spine involved with systemic mastocytosis in a 68-year-old woman. Baseline plasma histamine levels were obtained before irradiation and compared to levels obtained on the third, fifth, eighth, and tenth treatment days. Despite concerns regarding histamine release with mast cell destruction following irradiation, plasma histamine levels remained within normal limits. No change in dermatologic or other systemic manifestations were observed. No untoward systemic or localized sequelae associated with mast cell degranulation in response to the administered large field of radiation was observed. Effective palliation was accomplished, and it was concluded that radiation therapy can effectively be applied in treatment of systemic mast cell disease without significant morbidity.

Systemic mastocytosis--a case treated with interferon alpha and radiotherapy.

Systemic mastocytosis is uncommon. Symptoms result from local infiltration and degranulation of mast cells. Reports in the literature describe successful use of interferon alpha and radiotherapy to produce reduction in symptoms and bulk of disease. We report a patient who responded to radiotherapy but not interferon alpha.

Systemic mast cell disease (SMCD) and bone pain. A case treated with radiotherapy.

BACKGROUND: Systemic mast cell disease (SMCD) is a rare disease characterized by a multitopic proliferation of cytologically and/or functionally abnormal tissue mast cells. SMCD preferentially involves the skin, spleen, liver, lymph nodes and the bone marrow. The cause of SMCD is unknown. Bony pain, caused by mast cell infiltration of the marrow cavity, is present in up to 28% of cases and is frequently chronic and difficult to palliate with medical therapy. CASE REPORT: We report one case of refractory bone pain in a 54-year-old female Caucasian patient with advanced SMCD and associated bony involvement, which was treated with radiotherapy for pain palliation. Between 1995 and 1998, the patient was irradiated at four different locations: 1) right shoulder and proximal right humerus, 2) both hands, 3) both knees, 4) left humerus with a total dose of 40 Gy in 2.0 or 2.5 Gy daily fractions. RESULTS: Different results of pain palliation were achieved. In one location the pain was reduced for 55 months until her death due to disease progression, whereas in two other locations a pain control was maintained for 3 and 6 months after radiotherapy. In one location, no pain reduction was achieved. Severe side effects were not observed. CONCLUSION: Palliative radiotherapy has a role in the control of severe intractable bone pain in patients with advanced SMCD, though in some cases the effect may be short or incomplete. The observed palliation of pain can even differ in the same patient.