Sarcoidosis development during ulcerative colitis remission in a patient with a susceptible human leukocyte antigen serotype

The combination of sarcoidosis and ulcerative colitis (UC) is very rare, and its pathogenesis remains unknown. Hereditary factors as well as environmental factors have been speculated, including an association with the human leucocyte antigen (HLA) genotype. A 62-year-old Japanese woman with UC presented with complaint of a cough. Abnormal shadows were evident on the chest X-ray during mesalazine therapy. Multiple indolent subcutaneous nodules were also detected. Transbronchial lung and skin biopsies showed non-caseous epithelioid granulomas, which were pathologically compatible with sarcoidosis. After steroid therapy, she became asymptomatic and the abnormal shadows and subcutaneous nodules disappeared. HLA serological typing revealed that she harbored the sarcoidosis-related HLA-DR14 allele, as well as UC-related HLA-B52 and HLA-DR15 alleles. This case suggests that a susceptible HLA genotype may influence the onset of the combination of sarcoidosis and UC.