Microscopic polyangiitis associated with progressive colorectal cancer and lung squamous cell carcinoma

Abstract

  Microscopic polyangiitis（MPA）is the most prevalent anti-neutrophil cytoplasmic antibody（ANCA）-associated vasculitis（AAV）in Japan. Approximately 7% of cases of MPA are associated with primary cancers. The ratio of solid cancers in AAV-associated malignant tumors is extremely high（92%）, whereas that in malignant tumors associated with whole vasculitis syndrome remains 17%. We herein report a case of MPA with ANCA against myeloperoxidase（MPO-ANCA）that was associated with advanced colorectal cancer and lung squamous cell carcinoma. This is the first report of an MPA case simultaneously associated with different histological types of multiple solid cancers. Because of the deterioration of MPA, we started to treat the patient with 60 mg/day prednisolone and scheduled excision of the cancers after the treatment. However, the patient died due to invasive pulmonary aspergillosis during tapering of prednisolone. The solid cancers may have been associated with the onset and deterioration of MPA. Analysis of previous case reports suggested that treatment for the cancers improves the outcome of AAV（p < 0.05）, which should be carefully re-evaluated with increased number of cases. Systematic screening for solid cancers at the diagnosis of MPA is recommended due to the possibility of multiple cancer association.