The patient was a 45-year-old Chinese female, housewife and Han nationality. The patient found pelvic mass during physical examination a year ago, the clinical manifestations were intermittent lower abdominal discomfort, frequent urination, dysuria, no hematuria, no vaginal bleeding and so on. The outpatient clinic was admitted to the hospital with "pelvic mass". The patient was without any treatment before. Physical examination found a pelvic mass, did not care, untreated. Then intermittent lower abdominal discomfort, frequent urination, dysuria, no hematuria, no vaginal bleeding, and so on. B-ultrasound examination showed that the left side of the uterus was abnormally hypoechoic (10.4×9.6cm), the right ovary had no obvious abnormal echo, and the left ovary showed unclearly. Then she comes to our hospital, and the outpatient clinic is admitted to the hospital as a "pelvic mass". The patient was treated with abdominal hysterectomy and double salpingectomy, pelvic tumor resection, cystectomy, and ureterostomy under general anesthesia.
Magnetic resonance imaging(MRI)pelvic plain scanning showed that a large lobulated mass could be seen among the cervix, the anterior wall of the vagina, and below the bladder. The boundary of the mass was still clear. The range of the mass was about 12×11×10cm in size. T1W1 showed a slightly higher signal, T2W1 showed a high-low mixed-signal, and DWI showed a mixed high signal. An enhanced scan showed obvious uneven enhancement, uterine body, and cervical lifting. The bladder was connected tightly to the mass and compressed forward and upward (Fig. 1). A mass in the pelvis that lies between the uterus and the bladder and is closely connected to the base of the bladder and the wall of the uterus. After a complete hysterectomy, a huge mass was found between the anterior wall of the vagina and the posterior wall of the bladder, which was hard and fixed at the pelvic. The anterior boundary of the tumor was not separated from the posterior wall of the bladder and protruded into the bladder. When the bladder was completely dissociated from the extraperitoneal cavity, it was seen that the tumor originated from the posterior wall of the bladder and continued down to the anterior wall of the urethra to the pelvic floor.
The postoperative specimens were carefully observed to describe the size, color, texture, and other mass characteristics. The sampling processes, dehydration, embedded in paraffin, cut slides, and hematoxylin and eosin (H&E) staining were performed according to the requirements. A total cystectomy was performed with a volume of 15×12×5cm in whole tissues. A volume of 11×11×4.5cm in tumor size was seen at the posterior wall of the bladder. The section of the tumor was grayish-yellow, tough, and lobulated. The tumor involved the whole layer of the bladder wall, did not break through the bladder adventitia, and the boundary between the tumor and the surrounding tissue was still clear(Fig. 2).
The tumor tissue was separated by fibrous connective tissue, arranged in flake, nest and cord shape, showing infiltrative growth. The tumor cells were pleomorphic, round, polygonal, and fusiform. The ratio of the nucleus to the cytoplasm was increased. The cytoplasm was rich in red staining with a large number of eosinophilic bodies. The nuclei were heteromorphic with different sizes. Some of the nuclei were vacuolated and had obvious nucleoli. Multinucleated tumor cells and scattered coagulative necrotic foci were seen locally, and the mitotic figure was more than 5/50HPF(Fig. 3).
DAKO company's latest Omnis automatic immunohistochemical instrument was used for staining, and the process was carried out under the operation manual provided by the manufacturer. The sources, clones, and manufacturer of the antibodies used are shown in Table 1. Negative and positive controls were all set up for each antibody. The IHC results showed that S-100, NSE, CD68, CR, α-AT, and TFE-3 in the tumor cells were strongly positive, and the Ki-67 proliferation index in most of the tumor areas was around 15% (Fig. 4). The IHC results showed that SMA, Desmin,α-inhibin, GFAP, MyoD1, HMB45, and CK(pan)were all negative(not shown).
Next-generation high-throughput sequencing (NGS)covered 425 gene exons, fusion-related introns, variable splicing regions, and specific microsatellite (MS) sites, and other common 1.46Mb base sites was used in this study. The detection results included point mutation, small fragment insertion and deletion mutation, gene fusion and copy number variation, microsatellite (MS) analysis, and tumor mutational burden (TMB). The whole sequencing process was completed on the Illumina-based Hiseq 4000,performed at Nanjing Geneseeq Technology Inc., Nanjing, Jiangsu, China. The 425 genes sequenced include five functional partitions, which are key genes for targeted treatments, key genes for chemotherapy, genetic risk prediction genes, important tumor-driving genes, but there are no targeted drugs at present and key genes in the tumor-related signaling pathways. In the sequencing of the 425 genes, the results of NGS indicated that the overall mutation rate is very low. The results revealed that the EP300 gene was missense mutated (c.457A > G) with 33% mutation abundance. The gene of EP300 is in the classification of "key genes in the tumor-related signaling pathways”. The NGS results also showed that genes of DPYD(c.1627A > G), ERCC1( c.354T > C), NQO1(c.559C > T), TPMT(c.719A > G), and XRCC1(c.1196A > G) were polymorphic mutated, which these genes are all in the classification of " key genes for chemotherapy". The detailed locations and functions as shown in Table 2. NGS results also showed that the tumor mutational burden(TMB༉was very lower (2.1 mutations/Mb)༌and the microsatellite (MS) analysis showed that no MIS-H related genes were detected. The list of the 425 genes and functional partition was shown in supplement data (Table 3).
Three months after the first operation, the patient was re-admitted to the hospital because of "vaginal mass found for more than one week". Specialist examination: the right vaginal wall can reach a mass with a diameter of about 3cm, lobulated, moveable, tenderness, clear boundary, close to the orifice of the vulva. What was seen during the operation: the vulvar mass was located in the lower part of the vagina behind the right greater labia, lobulated, with a volume of about 4×3×1 cm, with a clear boundary and hard nature. MRI indicates local recurrence of the tumor. The pathological diagnosis after the second operation was consistent with malignant GCT with vulvar and cervical invasion. The patient died three months after the second operation.