We aimed to explore the diagnosis and treatment of peripheral primitive neuroectodermal tumors(pPNETs). We retrospectively analyzed the diagnosis and treatment process of a patient who was diagnosed with pPNETs by pathology. This case was a man with soft masses arising from the left chest wall near the armpit and left supraclavicular of a 47-year-old man. The patient mainly presented with the masses which increasing gradually with obvious pain. Needle biopsy showed that they were both metastatic adenocarcinoma. Ultrasonography B revealed blood flow of these two low density placeholders can be seen in the signal, not oppression axillary and vein. Radical resection of the masses were performed. Histopathologic study and immunohistochemistry(IHC) confirmed the masses to be peripheral primitive neuroectodermal tumors. pPNETs is a rare malignant small round cell tumor. CT and MRI examination can estimate the resectability of the tumor; Ultrasound B can make sure its inside blood supply and the positional relationship between the mass and the surrounding vasculature. The diagnosis of pPNETs is based primarily on histopathologic study and IHC, especially those with the characteristics of the Homer-Wright and neuroendocrine markers. Radical resection of the tumor is the most effective therapeutic method. The effect of adjuvant chemo-radiation is worth affirmation. Autologous stem cell rescue besides adjuvant chemotherapy has been associated with prolonged survival. We aimed to explore the diagnosis and treatment of peripheral primitive neuroectodermal tumors (pPNETs). We retrospectively analyzed the diagnosis and treatment process of a patient who was diagnosed with pPNETs by pathology. This case was a man with soft masses arising from the left chest wall near the armpit and left supraclavicular of a 47-year-old man. The patient mainly presented with the masses which increasing gradually with obvious pain. Needle biopsy showed that they were both metastatic adenocarcinoma. Ultrasonography B revealed blood flow of these two low density placeholders Histopathologic study and immunohistochemistry (IHC) confirmed the masses to be peripheral primitive neuroectodermal tumors. pPNETs is a rare malignant small round cell tumor. CT and MRI examination can estimate the resectability of the tumor; Ultrasound B can make sure its inside blood supply and the relationship between the mass and the surrounding vasculature. The diagnosis of pPNETs is based on on histopathologic study and IHC, especially those with the characteristics of the Homer-Wright and neuroendocrine markers. Radical resection of the tumor is the most effective therapeutic method. The effect of adjuvant chemo-radiation is worth affirmation. Autologous stem cell rescue besides adjuvant chemotherapy has been associated with prolonged survival.