An extragonadal germ cell tumor with dermatomyositis: A case report and literature review.

The risk of malignancy in inflammatory myopathy patients is well recognized. However, the incidence of germ cell tumor (GCT) with inflammatory myopathy is low, and most reported cases of GCT also exhibit testicular tumors. Therefore, a case of extragonadal GCT with dermatomyositis (DM) is reported in the current study to better understand this paraneoplastic syndrome. A 53-year-old man presented with bilateral cervical lymph node enlargement. A lymph node biopsy showed embryonal carcinoma, and computed tomography showed multiple lymph node and lung metastases. A period of one month after bleomycin, etoposide and cisplatin (BEP) chemotherapy, this patient developed an erythematous eruption over the extensor surfaces of bilateral fingers, or Gottron's sign and facial erythema. The patient was diagnosed with DM with a positive anti-TIF-1γ-antibody result. High-dose prednisolone was effective, and there has been no evidence of cancer recurrence for over one year. The literature review identified 17 cases of GCT with inflammatory myopathy that have been reported so far, and it was indicated that this is the first case of extragonadal GCT with DM following chemotherapy. This case highlights the importance of monitoring after the completion of cancer treatment, as distinctive dermal and muscular symptoms should cause us to consider the possibility of paraneoplastic inflammatory myopathy.