B24. Gonadal ovarian tumors

In an earlier version of this topic, I’d mistakenly believed that the topic name referred to ovarian sex cord-stromal tumours. Now, I’m sure that it actually refers to ovarian germ cell tumours (as the topics are identical for German and Hungarian program and the German and Hungarian names for this topic is literally “germ cell tumours”). Not sure how I made that mistake. I’ll leave the sex cord-stromal tumour topic below, but it shouldn’t be necessary to know.

Ovarian germ cell tumours (like teratoma) account for < 3% of ovarian cancers. They mostly affect younger women, rarely affecting those over 30. They’re most commonly benign. Most are diagnosed at an early stage and are highly curable (5-year survival > 95%).

Ovarian germ cell tumours

Ovarian germ cell tumours are those ovarian tumour which originate from primordial germ cells in the ovary. These can develop into foetus-like structures, placenta-like structures, extraembryonal structures, or grow completely undifferentially. It’s a heterogenous group of tumours with many different types with different characteristics.

Germ cell tumours have a much better prognosis than epithelial tumours, are more commonly benign, and they affect younger women. Germ cell tumours are relatively frequently bilateral, especially dysgerminoma.

Classification

• Teratoma
  • Dermoid cyst (mature teratoma)
  • Immature teratoma
  • Struma ovarii
• Dysgerminoma
• Yolk sac tumour
• Embryonal carcinoma

A teratoma is a germ cell tumour which grows into somatic structures originating from ectoderm, endoderm, and mesoderm. They may contain structures like hair and teeth. The benign mature teratoma (dermoid cyst) is more common than the malignant immature teratoma. Struma ovarii is a rare type of teratomy which consists of thyroid tissue and produces thyroid hormones. Anti-NMDA receptor encephalitis is associated with teratomas.

A dysgerminoma is a germ cell tumour which has grown into an undifferentiated structure. It’s more frequent in those with streak gonads. It’s the most common malignant ovarian germ cell tumour.

A yolk sac tumour is a germ cell tumour which has grown into a yolk sac-like structure. They characteristically produce AFP.

Embryonal carcinoma of the ovary is one of the most aggressive ovarian tumours. It’s very rare.

Clinical features

Ovarian cancer is characteristically asymptomatic until the late stages, which is part of the reason for the poor prognosis.

When symptoms do appear, these are the most common:

• Abdominal enlargement (due to ascites)
• Symptoms of pressure on surrounding organs
  • Dysuria
  • Constipation
  • UTI
• Symptoms relating to complications of the tumour (usually acute)
  • Torsion – acute pain and vomiting
  • Rupture – generalised abdominal pain
  • Haemorrhage – abdominal pain and haemorrhagic shock

Some present with an asymptomatic adnexal mass which is discovered on bimanual examination or on ultrasound. Germ cell tumours grow quickly and therefore often cause pelvic pain or symptoms of bladder or bowel compression.

Diagnosis and evaluation

Physical examination should be performed for an adnexal mass as well as inguinal and cervical lymphadenopathy. Ultrasound (usually transvaginal) of the adnexal mass can reveal features suspicious for malignancy (solid mass, irregularity, papillary structures, etc.) and ascites. Chest, abdominal, and pelvic CT or MRI are used to look for ascites and disease spread. FNAB is never performed as it may cause spreading.

The definite diagnosis of ovarian cancer, as well as determination of its histological type, requires histology. Biopsy causes tumour seeding and is not performed. All cases of suspected ovarian cancer undergo complete surgical staging, involving total hysterectomy with bilateral salpingo-oophorectomy with pelvic and paraaortic lymph node dissection and omentectomy. Peritoneal cytology is also acquired by peritoneal washing. Only after histological evaluation of these samples can the diagnosis be made.

It’s important to distinguish germ cell tumours from other ovarian tumours during the diagnostic evaluation, as the treatment is different. Germ cell tumours are more often solid on ultrasound than epithelial tumours. Because germ cell tumours frequently are bilateral, both sides must be examined (bilateral examination is performed routinely in all cases anyway). If germ cell tumour is suspected in a young girl, we may perform karyotyping (as the probability of intersex disorder is high). Ovarian germ cell tumours often produce tumour markers, especially hCG, AFP, and lactate dehydrogenase (LDH).

Management

Ovarian germ cell tumours often occur in fertile women, and as such special measures should be taken to preserve fertility if possible, if the patient wants to. If a germ cell tumour is highly suspected, bilateral oophoerctomy may not be required, and we may opt for fertility-sparing surgery instead (unilateral salpingo-oophorectomy with preservation of the uterus).

If the contralateral ovary appears to also be affected by the tumour at the time of surgery, we may resect this tumour affection while preserving the rest of the contralateral ovary to preserve fertility. Even if the whole tumour can’t be removed during surgery, cure is likely with adjuvant chemotherapy.

Adjuvant chemotherapy cures most patients with germ cell tumours as they’re highly chemosensitive. The standard chemotherapy regimen consists of bleomycin, etoposide, and carboplatin/cisplatin (BEP).