Steroid cell tumors not otherwise specified (NOS) are a rare subgroup of sex cord-stromal tumors. The tumors can occur at any age, although the mean age of occurrence is 43 years old. The majority are benign, but have the capability of producing one or more steroids associated with virilization. The present study reports the case of a 29-year-old female who presented to the Second Xiangya Hospital suffering from lower back and leg pain that had persisted for five months. The patient had regular menstrual cycles and no virilization symptoms were present. Laboratory investigations revealed normal hormone levels. Multiple areas of bone destruction and a right ovarian mass were confirmed via positron emission tomography/computed tomography. The patient underwent an exploratory laparotomy, and a mass measuring ~6 cm in diameter was subsequently identified in the right ovary. A right salpingo-oophorectomy and pelvic washings for cytology were performed. Histopathological studies confirmed the diagnosis of a malignant steroid cell tumor NOS of the right ovary. The patient underwent eight cycles of chemotherapy (docetaxel, 120 mg and nedaplatin, 80 mg). The patient continued to have relatively good health, with no deterioration of the condition for one year and a half, however, the disease progressed and the patient succumbed to brain metastases six months later.