VOJNOSANITETSKI PREGLED FIRST CASE REPORT OF A SOLITARY METASTASIS OF THE TRANSITIONAL CELL CARCINOMA OF THE OVARY TO THE SPLEEN

Background: Primary transitional cell carcinoma (TCC) of the ovary is characterized by the presence of papillary projections of malignant transitional epithelial cells or their aggregates in the fibrous stroma. This type of tumor represents nearly 1% of all ovarian surface epithelium carcinomas. Our aim was to create the first report of a solitary splenic metastasis of primary ovarian TCC. Case report: A 60-year-old female patient was admitted because of an asymptomatic splenic tumor in December 2018. Two years prior, she underwent total abdominal hysterectomy, bilateral adnexectomy, and infracolic omentectomy for primary TCC of the ovary. Control abdominal ultrasonography, computed tomography, and magnetic resonance imaging performed two years after primary surgery showed a splenic tumor. An open splenectomy was performed, with the intraoperative finding of a hilar splenic tumor and the absence of other pathological lesions in the abdomen. Frozen section analysis showed a TCC metastasis, which was subsequently confirmed by definitive histopathological examination. During the 1-year follow-up, there was no relapse of the disease. Conclusions: This is the first report of a solitary splenic metastasis of primary ovarian TCC, based on the literature review. This case may serve as an example of the diagnostic and therapeutical role of splenectomy in isolated splenic metastases of ovarian cancer. (vertical, laterolateral and anteroposterior diameter, respectively). The lesion showed diffusion restriction was hipovascular in comparison with the splenic parenchyma. The other imaging findings in the as well as the chest X-ray and head CT, were normal. The laboratory results showed that CA 125 was elevated (50.6 U/mL). Other results (full blood count, biochemical parameters, and other tumor markers) were normal.


Introduction
Ovarian transitional cell tumors may present as transitional cell carcinoma (TCC); as well as benign, borderline, or malignant Brenner tumor; in total accounting for nearly 2% of all ovarian tumors 1 . It is considered that Brenner tumors arise from the surface epithelium and stroma through the process of transitional cell metaplasia 2 , and that around 1% of all Brenner tumors are malignant 3 . Primary TCC of the female genital tract is described in the ovary, vagina, uterine cervix, endometrium, and Fallopian tubes 4 . Primary ovarian TCC was first described by Austin and Norris in 1987 5 . It represents 1% of all ovarian surface epithelium carcinomas 6 . The lack of urothelial markers suggests a Mullerian origin of TCC, therefore distinguishing it from urothelial cancer 7 . TCC is characterized by the lack of the Brenner component 8,9 and the lack of stromal calcification 10 . On the other hand, TCC shows malignant transitional type cells in papillary proliferations or aggregates in the fibrous stroma 6. Silva et al. showed that focal or diffuse ovarian TCC components presented in 88 of 934 ovarian cancer cases 10 . Primary ovarian TCC has a better prognosis in comparison with other ovarian carcinomas, due to a higher degree of chemosensitivity 6,7,10 .
Our aim was to create the first report of a solitary splenic metastasis of primary ovarian TCC, based on the histopathological examination and the medical history of the patient.

Case report
In December 2018, a 60-year-old female patient was admitted for elective splenectomy to treat an asymptomatic splenic tumor. In 2016, she underwent a total abdominal hysterectomy, as well as bilateral adnexectomy and infracolic omentectomy for a massive pelvic tumor. The initial imaging finding (abdominal computed tomography scan interpretation) did not show any evidence of other intraabdominal pathological lesions, confirmed by the operative report from primary surgery (which was not performed in our institution). Multiple biopsies from the visceral peritoneum (mesentery) as well as the parietal peritoneum (central, anterolateral and pelvic peritoneum) were taken. Histopathology of the pelvic tumor showed a primary ovarian TCC, with an infiltrative growth and partial necrosis; papillary projections of pleomorphic epithelial cells expressing multiple mitoses and acidophilic cytoplasm. Immunohistochemistry stain showed CK7 positivity and CK20 negativity. The tumor stage was determined as pT1c, histologic grade 2-3, and nuclear grade 3. The peritoneal biopsies were all negative. Afterwards, she underwent six cycles of chemotherapy (paclitaxel and carboplatin). Other medical history was unremarkable.
On admission, the patient did not report any symptoms, and the physical finding was normal (besides the scar from the previous laparotomy). The patients in Table 1 had a disease-free interval from 11 months to 5 years after splenectomy. The case presented herein exhibits splenectomy as a diagnostic step (to determine the presence of metastatic disease), as well as a curative approach (with a 1-year disease-free interval after surgery). This may serve as an inspiration to report solitary ovarian TCC metastases to the spleen; in order to recognize the true incidence of this metastatic pattern, as well as the therapeutic benefit from splenectomy.

Conclusion
This is the first case report of solitary ovarian TCC metastasis to the spleen.
Additionally, this case report serves as an example of therapeutic splenectomy in solitary TCC splenic metastasis. The follow-up of this patient, as well as reporting other similar cases in the future, will demonstrate the effect of this metastatic pattern and splenectomy on the 5-year survival rate and the disease-free interval in primary ovarian TCC.
Conflict of interest: none declared. * -relapse of cancer after splenectomy (the follow-up period is given in brackets); ** -no available information