Authors of a case report recently published in Acta Oncologica described a case of possible systemic mastocytosis (SM) following a female patient’s radiation therapy for breast cancer.
Red spots linked to radiation therapy
The case involved a 57-year-old woman who presented with red spots on her right breast and axilla. The patient had received chemotherapy and radiotherapy as well as a bilateral mastectomy to treat breast cancer seven months before the onset of symptoms. The patient did not report any other symptoms.
Physicians observed that the location of the lesions corresponded to where she had received radiation therapy seven months before. A biopsy of the lesion revealed abundant mast cells. Laboratory workup revealed elevated serum tryptase, a typical finding in SM.
Read more about SM testing and diagnosis
Physicians suspected systemic mastocytosis and performed a bone marrow biopsy, which revealed the presence of abnormal mast cells but not in enough quantity to fulfill the World Health Organization’s SM major diagnostic criteria. A polymerase chain reaction revealed a KIT mutation, one of the minor WHO SM diagnostic criteria.
The patient was diagnosed with pre-diagnostic SM, a term used for patients with features and symptoms suggestive of SM that do not meet the diagnostic criteria. In the last four years, the patient experienced only sporadic outbursts of dermatological symptoms with no systemic involvement.
Epidemiology on radiation-associated SM
The authors searched medical databases to find cases similar to this one. The search revealed 10 cases from 1950 to 2023 that reported SM following breast cancer radiation therapy in women aged 30 to 60.
Half of the patients had only dermatological symptoms; the remaining five had systemic symptoms, including bone pain, night sweats and hot flashes. All cases were mild and required either no treatment or treatment with antihistamines.
“Although rare, mastocytosis should be considered for any patient who presents with a new dermatitis after completing radiation therapy, especially for breast cancer,” the authors concluded. “As radiation-associated mastocytosis appears to have an indolent course, treatment should consist of observation and skin-directed therapies.”
