Primary Ovarian Small Cell Carcinoma of Pulmonary Type: Analysis of 6 Cases and Review of 31 Cases in the Literatures.

Objective Primary small cell ovarian cancer of pulmonary type (SCCOPT) is a rare ovarian tumor with a poor prognosis. The platinum-based chemotherapy is the standard treatment. However, there is little research on the clinical characteristics and potential benefits of other treatments due to its low incidence. The study aims to investigate clinicopathological characteristics and treatment of SCCOPT. Methods We performed a study in which the clinical, imaging, laboratory and pathological characteristics of 6 SCCOPT cases who were admitted to the Gansu Provincial Hospital from the year of 2008 to 2022 and of 31 cases reported in 17 English and 3 Chinese literatures were retrospectively summarized.Results The median age of these SCCOPT cases was 56.00 years. Almost 80% of them had a stage Ⅲ or Ⅳ tumor. All patients underwent an operation and postoperative chemotherapy. Nevertheless, all cases had a poor prognosis, with a median overall survival time of 12 months. Immunohistochemically, the SCCOPT of all patients showed positive expressions of epithelial markers, such as CD56 and sex-determining region of Y chromosome-related high-mobility-group box 2 (SOX-2), and negative expressions of estrogen receptor, progesterone receptor, vimentin, Leu-7, and somatostatin receptor 2. The tumor of above 80% cases expressed synaptophysin. Only a few cases expressed neuron-specific enolase, chromogranin A, and thyroid transcription factor-1. Conclusions SCCOPT had a poor prognosis. SOX-2 could be a biomarker used to diagnosis of SCCOPT.