Extradural Spinal Metastasis in Ovarian Mixed Germ Cell Tumor.

Ovarian germ cell tumors (GCTs) are rare and affect mainly young girls and women. Two histological groups are distinguished: dysgerminomas and nondysgerminomatous tumors. These tumors have initial good responses to surgery and chemotherapy in 80% cases, but >75% of patients die due to complications of disease progression. There are very few case reports of mixed GCT with extradural spine metastases. We report a rare case of a 17-year-old girl who had undergone left salpingo-oophorectomy with omental and peritoneal biopsy for ovarian GCT with extradural spinal metastasis.

INTRODUCTION

Ovarian germ cell tumors (GCTs) constitute approximately 15%–20% of all ovarian neoplasms. They are fast-growing neoplasms that arise from primordial germ cells derived from the embryonal gonad. Malignant GCTs comprise <5% of all ovarian neoplasms and their incidence range from 1% to 6% as reported in the West and from 8% to 19% in Asia.[1]

The yolk sac tumor (also known as endodermal sinus tumor) is the second most common GCT, constitutes 20% of all cases, and is common in girls and young adults with an average age of 19 years. There are case reports of intramedullary spinal cord metastasis from GCT,[2] but extradural spinal metastasis is very rare.

Hereby, we present a comprehensive literature review to date of case that includes any description of mixed GCT with extradural spinal metastases.

CASE REPORT

A 17-year-old female patient presented to us with the chief complaints of backache with abdominal pain and abdominal distension for 5 months, sudden onset paraplegia and bladder and bowel incontinence for 1 day. On examination of spine, local tenderness was present at D9–D10 level. The patient had spastic paraplegia with bilateral exaggerated knee and ankle reflexes and bilateral extensor plantar reflex associated with clonus and reduction in sensation of all modalities below D10 dermatome.

She had a history of left ovarian GCT for which she was operated 25 days before. The patient underwent staging laparotomy. Large left-sided ovarian mass 30 cm × 25 cm filling entire abdominal cavity extending into liver, spleen, and lateral parities. Left lateral salpingo-oophorectomy was done with omental and peritoneal biopsy. Histopathology report revealed mixed GCT with predominant component of yolk sac tumor involving ovarian capsule and showed diffuse areas of necrosis and moderate nuclear pleomorphism suggestive of mature teratoma. The patient had raised levels of tumor markers such as lactate dehydrogenase (LDH), alpha-fetoprotein (AFP) (37,800 ng/ml), carcinoembryonic antigen (CEA) (29.1 ng/ml), CA-125 (259.35 U/ml) preoperative with normal levels of beta-human chorionic gonadotropin (β-HCG). The serum levels of CEA (5.2 ng/ml) decreased after surgery to normal while levels of AFP (22,500 ng/ml) and CA-125 (161.2 U/ml) decreased substantially postoperatively. The patient was advised chemotherapy in the postoperative period.

The patient was evaluated for severe backache and sudden onset paraplegia with urinary retention. Magnetic resonance imaging spine showed multiple D6–D8 level vertebral metastasis and extradural compression suggestive of compressive myelopathy [Figure 1a–d]. Contrast-enhanced computed tomography (CECT) scan of the abdomen showed retroperitoneal lymphadenopathy with mild ascites. CECT spine revealed lytic destruction and partial collapse of D9 vertebral body and bilateral paravertebral soft-tissue lesions (D6–D8) with the erosion of D7 vertebral body suggestive of metastasis. She underwent urgent decompressive spinal surgery after consent. D6–D9 laminectomy with decompression of tumor was done, with frozen section suggestive of poorly differentiated carcinoma. Grossly, tumor was bluish black, soft, suckable present in the extradural region of D6–D8 and was adhered to the underlying dura. The final histopathology report of the tumor was consistent with mixed GCT, having Schiller–Duval bodies and few hyaline globules. Tumor cells were positive for CD117 and focally positive for AFP, which was consistent with yolk sac tumor. The patient received adjuvant postoperative chemoradiotherapy [Figures 2 and 3a, b]. Now, the patient is in partial remission, and neurological symptoms are appropriately decreased.

Figure 1

T2 sagittal magnetic resonance imaging image (a) and T1 sagittal magnetic resonance imaging image (b) showing hypointense lesion in the extradural space from D6 to D9 compressing the cord with myelomalacic changes in the spinal cord and D9 vertebral body collapse. T2 axial magnetic resonance imaging image (c) and T1 axial magnetic resonance imaging image (d) showing hypointense lesion in the extradural space with D9 vertebral collapse and compressing the spinal cord

Figure 2

Tumor cells in sheets with pale moderate amount of cytoplasm, vesicular pleomorphic nuclei with specs of bone (H and E, ×10); inset picture (H and E, ×20) showing mitosis (white arrow) and multiple eosinophilic material as globule (black arrows)

Figure 3

(a) Tumor cells are positive for CD117 (IHC, ×20); (b) tumor cells positive for alpha-fetoprotein (IHC, ×20)

DISCUSSION

Ovarian mixed germ cell neoplasms are thought to be derived from primitive germ cells of the embryonic gonad and constitute the second largest group responsible for 15%–20% of all ovarian neoplasms.[3] Malignant ovarian GCTs are uncommon accounting for only about 5% of all malignant ovarian neoplasms.[4]

Of all the GCTs, the yolk sac tumor is the second most common, after dysgerminoma accounting for 20% of all cases, and is seen in girls and young adults with a mean age of 19 years. These tumors can occur in women at any age, but peak incidence is usually during the early 20s.[5] In children and adolescents, more than 60% of ovarian tumors are of germ cell origin, of which approximately one-third are malignant. The vast majority of GCTs in adults are benign (nearly all mature cystic teratomas).

Mixed germ cell tumors of the ovary contain two or more elements of the lesions. Microscopically, a dysgerminoma component is present in 80%, endodermal sinus tumor in 70%, immature teratoma in 53%, while choriocarcinoma in 20% and embryonal carcinoma in 16%.[6] In our case, the yolk sac tumor and teratoma constitute the two elements. Our patient at diagnosis was a 17-year-old young girl which is the usual age for mixed GCT. She had extradural spinal metastasis which is relatively uncommon.

Endodermal sinus tumor of the ovary constitutes the second most common and represents about 20% of all ovarian GCTs.[7] It is usually seen in children and young adults (median age 19 years) presenting with abdominal pain and rapidly growing mass. Schiller–Duval body is pathognomonic, with central blood vessel encased by germ cells within a space similarly lined by germ cells, resembling glomerulus with hyaline droplets present in all tumors (positive for AFP, periodic acid-Schiff, and alpha-1-antitrypsin). It produces AFP and alpha-1-antitrypsin with absent or negligible HCG.[8] It is fatal without chemotherapy as most have subclinical metastases at presentation. Even patients with teratoma have raised levels of AFP. Our patient had raised levels of LDH, AFP, CEA, CA-125 preoperative with normal levels of β-HCG, and serum levels of CEA decreased after surgery to normal while levels of AFP and CA-125 decreased substantially postoperatively.

Both osseous and extradural metastasis are uncommon. In our case, there was osseous metastasis at D9 vertebrae with extradural metastasis which may be an extension of osseous metastasis, but we could not prove it or rule it out. Osseous metastasis has been reported which is even very uncommon. Our case had metastasis to the body of vertebrae.

In case of spinal metastasis, various treatment modalities are used such as radiotherapy, chemotherapy, and surgery. Emergency surgical decompression is required in few conditions such as bleeding, progressive neurologic deficit, and acute deficit. The decision for spinal decompressive surgery was made on urgent basis in this case based on progressive neurologic deficit with radiographic evidence of extradural metastasis. However, in the absence of acute progressive neurologic deficit or evidence of considerable instability, caution in surgical decision-making should be exercised. Emergency surgery for severe rapid-onset neurologic deficit due to compression should always be considered with the increased surgical risks explained because of bleeding or complications resulting from systemic tumor burden.

Mixed GCT is a very rare tumor. Treatment consists of salpingo-oophorectomy with adequate staging biopsies with postoperative combination chemotherapy can effectively improve the prognosis of these patients.[4] Chemotherapeutic regimens have emerged to combination therapy with overall disease-free survival rates of more than 95%.

CONCLUSION

Extradural spinal metastatic from mixed GCT is exceedingly rare and requires aggressive multidisciplinary treatment approach. Careful initial surgery with adequate staging biopsies with postoperative chemotherapy regimens can greatly improve the prognosis of these patients. Spinal surgery has a limited role in these cases but can be considered for the progressive neurologic deficit. However, careful long-term follow-up of such cases is required.

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Conflicts of interest

There are no conflicts of interest.