Even when CT scan detected neoplastic swelling of the cervical lymph nodes and FDG PET/CT showed abnormal uptake in the pharynx, laryngoscopy did not show any signs of malignancy. for the prognosis of DM. We present a 17-AAG (KOS953) case of DM with esophageal fistula in whom blind mucosal biopsy was needed to diagnose oropharyngeal carcinoma. Case Report A 65-year-old Japanese male visited our hospital in August 2010. The physical findings were heliotrope rash with periorbital edema, Gottron’s sign on the dorsum of the hands 17-AAG (KOS953) (fig. ?(fig.1)1) and erythema of the upper arms. He complained of myalgia and slight muscle weakness. He had a prior history of surgical operation for maxillary cancer 27 years before. Laboratory examinations showed almost normal values for complete blood cell counts but elevated levels of aspartate aminotransferase (185 U/l), alanine aminotransferase (106 U/l), lactate dehydrogenase (637 U/l), C-reactive protein (0.5 mg/dl) and creatine kinase (5,518 U/l). The 17-AAG (KOS953) anti-nuclear antibody titer was 1:40, and autoantibodies, including anti-Jo-1, anti-ss-DNA, anti-ds-DNA, anti-Sm, anti-Ro (SS-A), anti-La (SS-B) and anti-RNP antibodies were not detected using enzyme-linked immunosorbent assay. Immunoprecipitation assays revealed the presence of anti-transcription intermediary factor 1 (anti-TIF-1) antibody. Histopathological examination of a biopsy specimen taken from the Gottron’s lesion revealed vacuolar degeneration of the basement membrane zone and perivascular lymphocyte infiltration (fig. ?(fig.2).2). A deltoid muscle biopsy showed degenerated muscle fiber and infiltration of mononuclear cells. Electromyography showed no myogenic change. Screening for internal malignancy using upper and lower gastrointestinal endoscopy and total body computed tomography (CT) scan showed no abnormality, especially no malignancy or interstitial lung disease. We diagnosed the patient with DM and initiated treatment with prednisolone at 80 mg/day. Blood chemistry examination and symptoms improved; hence, the dosage of prednisolone was gradually reduced. Open in Cbll1 a separate window Fig. 1 Clinical presentation. Gottron’s sign on the dorsum of the hands were observed at initial visit. Open in a separate window Fig. 2 Histopathological findings in a skin biopsy specimen taken from the Gottron’s lesion. Vacuolar degeneration of the basement membrane zone and perivascular lymphocyte infiltration were observed (hematoxylin & eosin staining, original magnification 100). In December 2010, the patient began to experience dyspnea. Laryngoscopy showed edema of the left pharynx, pressed larynx and narrowed glottides. A neck and chest CT 17-AAG (KOS953) scan demonstrated posterior neck abscess and massive free air from the submandibular to superior mediastinum areas without any sign of malignancy. Upper gastrointestinal endoscopy revealed posterior esophageal fistula. Antibiotic treatment for about 3 weeks led to improvement of the posterior neck abscess and esophageal fistula without 17-AAG (KOS953) surgery. In May 2011, widespread erythema over the upper body was observed (fig. ?(fig.3),3), and laboratory examination revealed an elevated serum creatine kinase level of 1,517 U/l. Although we increased the dosage of prednisolone from 10 to 15 mg/day, the serum creatine kinase level did not decrease. Therefore, we added intravenous immunoglobulin therapy. Repeated examination for internal malignancy with CT scan, gallium scintigraphy and upper and lower gastrointestinal endoscopy showed no recurrence of neck abscess or malignancy, except for intraepithelial neoplasia of the esophagus. Intravenous immunoglobulin therapy did not lead to complete remission of the serum muscle enzyme levels and skin erythema. Open in a separate window Fig. 3 Clinical presentation. Widespread erythema all over the upper body was observed in May 2011. In August 2011, the creatine kinase level was elevated again (629 U/l) with concomitant dysphagia. Total body CT scan showed swelling of the right cervical lymph nodes and multiple nodules in both the lungs and liver. Histopathological examination of a biopsy specimen taken from a cervical lymph node presented poorly differentiated squamous cell carcinoma. Since the original lesion of the carcinoma was unidentified, fluorine-18-fluorodeoxyglucose positron emission tomography (FDG PET)/CT scan was performed which revealed uptake in the pharynx. Laryngoscopy still showed no abnormality or sign of malignancy in the pharynx..