The Oral Squamous Cell Carcinoma (OSCC) frequently metastasizes lymphogenously. Haematogenous dissemination is less common. This report describes a rare case of a metastatic OSCC of the floor of the mouth to the patients' left upper arm. This is the first case described in literature as far as we know. Twelve months after R0 tumor resection surgery, including microvascular reconstruction of the lower jaw and followed by adjuvant radiotherapy, the patient was admitted for osteosynthesis plates removal. During clinical examination a tumor situated at his left upper arm was detected. According to the patient the tumor has demonstrated a rapid growth. Macroscopic appearance and conventional imaging led to the differential diagnosis of an abscess. MR-imaging could not differentiate between a tumor of soft tissue origin and a metastasis. A biopsy was taken and the pathological examination confirmed the diagnosis of an OSCC metastasis. The postoperative interdisciplinary tumor board recommended radiation therapy. Due to the fact that patients with regional lymph node metastases have a higher probability to develop distant metastasis a more detailed screening might be considered - especially when hemangiosis carcinomatosa was found histologically or macroscopically. Keywords: Mouth neoplasms, Neoplasm metastasis, Upper arm metastasis, Soft-tissue metastasis, Metastatic OSCC