Primary peritoneal carcinoma (PPC) is a rare malignancy with clinical features and management similar to epithelial ovarian carcinoma (EOC). Lymph node involvement in EOC or PPC is commonly seen in the presence of advanced disease with peritoneal involvement and rarely a presenting symptom. We describe a rare case of PPC in a 74-year-old woman presenting with widespread lymphadenopathy, radiologically mimicking lymphoma without peritoneal involvement. To our knowledge this is the only case of PPC presenting with supraclavicular and widespread lymphadenopathy, in the absence of macroscopic disease. This case may represent a distinct clinical entity from the usual peritoneal dominant form of EOC or PPC and highlights important clinical and biological aspects of PPC.