When diagnosis of dermatomyositis is made, malignancy work-up including serum tumor marker, esophago-gastro-dudoenoscopy, colonoscopy, chest CT, and abdominal CT should be aggressively performed. variable temporal relationship between the two conditions [15]. Malignant tumors originating from lung, breast, ovary, and gastrointestinal track are known to be frequently associated with dermatomyositis [24]. However, lymphoma or other hematologic malignancies rarely cause dermatomyositis [6,7]. Moreover, primary pleural lymphoma, as in this case, is an extremely rare malignancy [8,9], and no case associated with dermatomyositis has been reported till date. We describe a case of dermatomyositis that preceded the recurrence of malignancy in a patient with a very rare condition of primary pleural lymphoma. This case intensified the CiMigenol 3-beta-D-xylopyranoside malignancy evaluation when dermatomyositis is usually diagnosed, even in rare conditions. Furthermore, this case also demonstrates a good capability of18F-fluorodeoxy glucose (FDG) for CiMigenol 3-beta-D-xylopyranoside detection of malignancy recurrence as well as the involvement of dermatomyositis. == Case Report == A 65-year-old female was admitted with generalized edema and muscle aching, and weight gain of 6 kg for 1 month. She has been followed with a diagnosis of primary pleural lymphoma. The diagnosis was made via incidentally detecting a few scattered atypical cells in the pleural effusion 2 years previously, which was consistent with small lymphocytic lymphoma. No further lymphoma involvement was found at the time of diagnosis and during the follow-up period. At admission, physical examination detected skin rash in the shoulder, neck, wrist and right thigh areas. Initial laboratory tests revealed a high erythrocyte sedimentation rate (34 mm/h; normal range, 0-20) and elevated C-reactive protein level (2.02 mg/dl; normal range, 0-0.5), and also detected increased levels of creatine kinase (8,680 U/l; normal range, 30-225), lactate dehydrogenase (968 U/l; normal range, 100-220) and aldolase (37.4 U/l; normal range, <7.6) in the serum. Further, the level Elf1 of myoglobin in the serum (1,253 ng/ml; normal range, 0-65) was markedly increased. Muscle biopsy was performed at the CiMigenol 3-beta-D-xylopyranoside right biceps and first dorsal interosseus muscle. Histopathologic examination demonstrated moderate interstitial infiltration of lymphocytes, and ultrastructural examination disclosed microtubulovesicular bodies, which is a useful diagnostic marker of dermatomyositis, in the cytoplasm of endothelial cells (Fig.1). Sequential electromyographic examination also provided a feature of active myopathy; increased insertion activity, fibrillation potential, and complex repetitive discharge. == Fig. 1. == Electomicroscopic obtaining showing microtubulovesicular bodies (arrowed) in the cytoplasm of endothelial cells, a CiMigenol 3-beta-D-xylopyranoside diagnostic marker of dermatomyositis (transmission electron microscope 22,400) The diagnosis of dermatomyositis was finally made based on the typical skin rash, proximal muscle weakness, elevated level of serum muscle enzymes, findings of histopathology of the muscle biopsy and the finding of electromyogram showing a myopathic pattern, which satisfied the criteria for diagnosis of polymyositis and dermatomyositis. Several studies for the evaluation of residual lymphoma or other occult malignancy were performed, including serum tumor marker, esophago-gastro-dudoenoscopy, colonoscopy, chest computed tomography (CT), and abdomino-pelvic CT, and unremarkable findings were reported. On18F-FDG covering from upper thigh to the head, diffusely increased FDG uptake was observed in the proximal areas of upper arms and thighs, shoulder and pelvic girdle along the major muscle layers bilaterally, where dermatomyositis pathology is commonly involved (Fig.2). Additionally, a nodular lesion in the left supraclavicular area and a few suspicious hypermetabolic nodules in the retroperitoneal areas were examined on18F-FDG positron emission tomography (PET), and recurrence of malignancy was suspected. Bone scintigraphy also showed extraosseous accumulation of Tc-99m HDP in the soft tissue of the both upper arms and both thighs without evidence of bone metastasis. The distribution of radiotracer on bone scan was in semblance of that on18F-FDG PET. Although the recurrence of lymphoma in the supraclavicular and retroperitoneal area was suspected on the18F-FDG PET images, the patient wanted to delay further work-up, such as tissue confirmation, after the relief of the symptoms of dermatomyositis. Hence, the patient was treated with high-dose steroid and azathioprin without any further work-up. == Fig. 2. == 18F-FDG PET findings. A focal hypermetabolic nodule in the left supraclavicular area on18F-FDG PET was suspected as a recurred malignancy (white arrow); and18F-FDG uptake.