The clinicopathologic features of 35 cases of serous carcinoma of the ovary, fallopian tube, or peritoneum presenting as lymphadenopathy are described. The cases were retrieved from the files of the Department of Pathology at the University of Texas M. D. Anderson Cancer Center from a 20-year period (1982-2002). The following parameters were evaluated: patient age at diagnosis, lymph node involved, primary tumor site, tumor histology, peritoneal disease status, and survival. The patients ranged in age from 30 to 85 years (mean, 59 years). The lymph nodes involved were inguinal, 20 cases; supraclavicular, 11 cases; axillary, 2 cases; cervical, 1 case; and retroperitoneal, 1 case. Primary tumor sites included 20 ovarian, 10 peritoneal, and 2 fallopian tube. In 2 patients, total abdominal hysterectomy/bilateral salpingo-oophorectomy and complete staging showed no additional tumor, and in 1 patient with a previous history of total abdominal hysterectomy/bilateral salpingo-oophorectomy for a benign condition, imaging studies did not identify a primary site. The carcinoma was high grade in 30 cases and low grade in 4 cases. In one case, the diagnosis was made on cytology material and the tumor could not be graded. Peritoneal disease status was known in 33 patients and was as follows: omentum with gross disease, 16 cases; and omentum without gross disease, 17 cases. Follow-up was available in 33 patients and ranged from 4 to 204 months, with a median survival of 36 months for stage III patients and 29 months for stage IV patients. Patients with adenopathy and minimal peritoneal disease (grossly negative omentum) had a median survival of 120 months compared with 24 months for those with bulky peritoneal disease (grossly positive omentum). Serous carcinoma of the ovary, fallopian tube, or peritoneum presenting as a lymph node metastasis is uncommon. In rare cases, a primary site may not be found. The median survival of the patients for stage is not appreciably different from those patients presenting in the usual fashion, suggesting that this atypical presentation does not adversely affect survival. Patients with minimal peritoneal disease and extra-abdominal lymph node metastases survive longer than those with bulky peritoneal disease