A Case Report of Synchronous Lung Adenocarcinoma and Systemic Mastocytosis

Systemic mastocytosis(SM) is an extremely rare disease and is characterized by clonal proliferation of mast cells in any part of the body. SM patients are prone to developing cancer. Although the relationship between lung adenocarcinoma and SM is unclear, they share similar mutations. A female patient in her 40s presented with complaints of shoulder pain and unexpected weight. Later, the patient was diagnosed with lung adenocarcinoma. Additionally, systemic mastocytosis was detected while investigating her B symptoms and anemia. Induction chemotherapy with carboplatin and paclitaxel was decided as initial treatment. She did not respond to 3 cycles of this chemotherapy regimen. Radiotherapy with etoposide and cisplatin was applied as second-line treatment. Although the size of the lung adenocarcinoma was stable, her anemia, shoulder pain, B symptoms, and cachexia improved after second-line treatment. We present a case of synchronous lung adenocarcinoma and systemic mastocytosis presenting with B symptoms and shoulder pain.