A 72-year-old male was admitted with painful swelling of his left arm. Physical examination revealed supraclavicular lymphadenopathy with swollen left arm and a stony-hard prostate on rectal examination. Routine blood tests were normal. Doppler test showed deep vein thrombosis in the left arm. Tomography of chest, abdomen and pelvis showed generalized lymphadenopathy, suggesting lymphoma. Biopsy of a left supraclavicular node revealed adenocarcinoma of unknown origin. Colonoscopy and gastroscopy revealed no mass lesions. Total serum prostate-specific antigen (PSA) was 1000 ng/ml. Neoplastic cells were positively stained for PSA. Bone scintigraphy revealed abnormal uptake in T5 vertebra and sacrum. The patient was treated with subcutaneous enoxaparin and referred to oncologic care.