Malignant Lymphoma in the Psoas Major Muscle.
An 84-year-old Japanese man taking warfarin to prevent cerebral infarction secondary to atrial fibrillation was admitted to our hospital for evaluation of a painless right back mass. Magnetic resonance imaging (MRI) showed an oval-shaped mass in the right psoas major muscle. The mass showed high intensity on T1-, T2-, and diffusion-weighted imaging and mimicked an acute-phase hematoma. However, it showed no chronological changes typical of a hematoma, and MRI revealed enlargement of the mass 1 week after admission. Histopathological examination of a biopsy specimen revealed diffuse large B-cell lymphoma (DLBCL). Although skeletal muscle lymphoma is rare, physicians should be familiar with its MRI characteristics. In addition, determination of the lymphoma subtype has important implications for the treatment of skeletal muscle lymphoma because DLCBL may have an especially poor prognosis.
Department of General Medicine, National Hospital Organization Shibukawa Medical Center, 383 Shiroi, Shibukawa, Gunma 377-0280, Japan.
Nobuhiro
0000-0002-1204-1294
N
Akuzawa
Department of Internal Medicine, Japan Community Health Care Organization Gunma Chuo Hospital, 1-7-13 Koun-cho, Maebashi, Gunma 371-0025, Japan.
Takashi
T
Hatori
Department of Radiology, Japan Community Health Care Organization Gunma Chuo Hospital, 1-7-13 Koun-cho, Maebashi, Gunma 371-0025, Japan.
Aya
A
Takase
Department of Radiology, Japan Community Health Care Organization Gunma Chuo Hospital, 1-7-13 Koun-cho, Maebashi, Gunma 371-0025, Japan.
Jun
J
Aoki
Department of Pathology, Japan Community Health Care Organization Gunma Chuo Hospital, 1-7-13 Koun-cho, Maebashi, Gunma 371-0025, Japan.
Shinji
S
Sakurai
Department of Medicine and Biological Science, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma 371-8511, Japan.
Masahiko
M
Kurabayashi