Unusual Complication of Ewing Sarcoma of Vulva: Case Report

Introduction 

Primary Ewing sarcoma (ES) and primitive neuroectodermal tumor (PNET) are two members of the Ewing sarcoma family of tumors. These tumors are characterized by a t (11;22) (q24; q12) chromosomal translocation. Although this malignant round cell tumor is aggressive, fortunately, it is sensitive to chemotherapy. Generally, ES/PNET is unusual in the female external genital. Immunohistochemical stains and molecular cytogenetic analysis requires to confirm. Primary ES of the vulva is an extremely rare tumor with only 10 molecular confirmed reported cases up to now. (1,3) Urinary retention, in this case, is an unusual manifestation in which the technique of catheterization with two catheters could be interesting, as well. Herein, we describe a 15 years-old female patient with advanced ES of the vulva and urinary retention during chemotherapy. 

Case Presentation

The patient was a 15 years-old girl referred by slowly progressing swelling of the vulva from two months ago. The patient agreed to report her case after signing the informed consent and the report is based on CARE guidelines. When its color changed to black the patient came to the pediatrician. The patient is admitted to the hospital and underwent Magnetic resonance imaging (MRI) and tumor incisional biopsy. The patient had no history of specific clinical diseases or previous surgery. Examinations revealed vulva swelling preferably on the left side and swelling was noted over her vulvar region measuring 15 cm × 15 cm with a 7 cm × 7 cm necrosis region on the inferior left lateral site (Figure 1).

In laboratory data, creatinine was normal and urine culture was negative. The liver function test and complete blood count haven’t any abnormality. Pelvic MRI showed 15 cm × 15 cm. mass in pelvis, vulva region, and spinal skeletal metastasis (Figure 2). There were multiple lung metastases on the chest x-ray, as well. The pathology report showed a malignant round cell tumor with monomorphic cells with cortical pubic bone destruction. Immunohistochemistry (IHC) study showed tumor cells displayed CD99, NIKX2 in all cells and proliferative capacity of KI-67 in 40% of tumor cells, but negative staining with desmin, myogenin, CD56, CK, EMA, synaptophysin, chromogranin, and leukocyte common antigen. Thus ES/PNET has been concluded. In Bone marrow aspiration and biopsy, a small round cell tumor was observed, as well.

Then, the patient underwent chemotherapy with a VAC regimen (Vincristine, doxorubicin, and cyclophosphamide). Urinary retention occurred during one of the chemotherapy courses. Ultrasound examination showed 600 ccs of urine in the bladder. A urologic consult is done. Since the anatomy of the pubis and vulva is distorted, the meatus couldn’t find, so the blind catheterization was done using a 14 Fr foley catheter. Unfortunately, this catheter came into the vagina. So, without removing this one, the second 14 Fr foley catheter was inserted above the first catheter and it was successfully guided into the urinary bladder (Figure 2).

The patient was discharged with good general condition. After four months during the first months of the COVID-19 pandemic, the patient came to the emergency ward with respiratory distress and low serum oxygen saturation level. She was admitted and underwent a lung computed tomographic (CT) scan, in which a bronchopneumonia pattern was reported. COVID-19 was considered for a primary diagnosis, however, she, unfortunately, expired before the COVID-19 polymerase chain reaction test. 

Figure 1. Magnetic resonance imaging (MRI) of the tumor