Author(s)

Hiroyuki Tsuchie^1*, Seiya Miyamoto¹, Yoichi Kataoka², Seietsu Senma¹, Yuichiro Narita¹, Yuji Hatakeyama¹, Moto Kobayashi³, Kana Sasaki¹, Yoichi Shimada⁴

¹Division of Orthopedic Surgery, Nakadori General Hospital, Akita, Japan.
²Joto Orthopedic Clinic, Akita, Japan.
³Division of Orthopedic Surgery, Hiraka General Hospital, Yokote, Japan.
⁴Department of Orthopedic Surgery, Akita University Graduate School of Medicine, Akita, Japan.

Interstitial pneumonia develops not only as a rheumatoid arthritis (RA) manifestation, but also due to the side effects of drugs for its treatment, leading to the necessity of regular examinations. Krebs von den Lungen-6 (KL-6) is often used to check the activity of interstitial pneumonia in RA patients. However, this marker is also produced by some malignant tumors, and a high level of serum KL-6 has been reported in cancer patients. We describe herein 2 cases of RA with the complication of a malignant tumor not involving the lung, although there is no lesion in the lung regardless of the high level of serum KL-6.

KL-6, Malignant Tumor, Rheumatoid Arthritis, SP-D

Tsuchie, H. , Miyamoto, S. , Kataoka, Y. , Senma, S. , Narita, Y. , Hatakeyama, Y. , Kobayashi, M. , Sasaki, K. and Shimada, Y. (2015) Rheumatoid Arthritis with High Serum KL-6 Complicating Malignant Tumor: Two Case Reports. Open Journal of Orthopedics, 5, 41-45. doi: 10.4236/ojo.2015.53006.