Giant ovarian solid and cystic masses mixed with three types of tumors: A rare case report and literature review.

BACKGROUND

Most ovarian tumors exhibit a pure histological characteristic. Nevertheless, a combination of tumors with the same histogenetic origin but different histologic subtypes is relatively common. Additionally, co-occurrence of tumors with different histogenetic origins is very rare. Typically, these mixed tumors include mixed epithelial tumors, mixed epithelial-stromal tumors, mixed germ cell-sex cord-stromal tumors, and mixed germ cell tumors. However, mixed epithelial-sex cord stromal-lymphohematopoietic system tumors are rare. Currently, clinicians have limited knowledge of this type of tumor, and the epidemiology, diagnosis, and treatment of this disease are yet to be established.

CASE PRESENTATION

We report a case of a 73-year-old woman with abdominal distension and pain for three months. Imaging evaluation revealed a large pelvic mass, with ultrasound suggesting a benign ovarian cyst along with leiomyoma. Furthermore, computed tomography (CT) and magnetic resonance imaging (MRI) revealed a malignant tumor. Blood tests showed significant increases in CA125 and CA199 levels. The patient underwent a total abdominal hysterectomy and bilateral salpingo-oophorectomy. During the surgery, a large multinodular cystic solid mass was observed in the right ovary, and the maximum nodular diameter was 14.2 cm. The solid areas of the mass appeared gray-white and taupe, whereas the cystic areas contained clear liquid with smooth walls 0.2 cm thick and no intracystic solid areas. The left ovary had solitary nodules, the largest being 4 cm in diameter. Microscopic examination of the right ovary revealed three different cell types. The first type of cell area was analogous, round, fusiform, and staggered mixed cells with unclear boundaries and rare nucleolus or mitosis. The second type of cell area was the cystic dilatation area. The cyst wall was covered with a single layer of flat epithelium, rich eosinophilic cytoplasm, uniform nuclear chromatin, and no papillary structures. The third type was a diffuse lymphoid region with uniform medium-sized cells, rough nuclear chromatin and evident nucleoli and mitosis. The morphology of the left ovarian cell was single, which was consistent with the first type of cell area in the right ovary. Immunohistochemistry of the right ovary indicated that the first region expressed vimentin, inhibin-α, calretinin, SF-1, WT-1 and CD56, with Ki-67 at 5 %, and no CKpan expression. The second region expressed CKpan, with Ki-67 at 1 %. The third region expressed CD20, Pax-5, Bcl-6, Bcl-2, MUM1, CD45, and C-myc, with Ki-67 at 70 %, and positive IGH clonal gene rearrangement. Lastly, the pathological diagnosis was a mixed ovarian tumor in the right ovary, comprising thecoma-fibroma, serous cystadenoma, diffuse large B-cell lymphoma, and a thecoma-fibroma in the left ovary. A follow-up examination of the patient after 15 months showed no mass or lymph node enlargement in other parts of the body, and no recurrence or metastasis was observed.

CONCLUSIONS

We present a case of a postmenopausal woman with a rare combination of thecoma-fibroma, serous cystadenoma and diffuse large B-cell lymphoma in the ovary. To the best of our knowledge, this is the first reported case of such a combination. Typical pathological morphology and immunohistochemistry are crucial for the diagnosis of this disease. Owing to the limited knowledge of the disease, its pathogenesis and tissue origin are unknown. Clinicians should be careful about such patients. We believe this case report may provide some novel insights into the diagnosis and therapy of patients with this type of tumor.