Serous Tumours

Serous tumours are the most common tumour of the ovary, and serous adenocarciomas make up 30% of surface epithelial-stromal tumours. This group of tumours form structures that resemble the fallopian tube epithelium.

Serous Adenocarcinoma

Epidemiology

The most common malignancy of the ovary. Most of the epidemiological features described in the section on surface epithelial-stromal tumours applies. Suffice to say, it is more common in the West with an average age at diagnosis of 60.

Aetiology

Most risk factors described in the surface epithelial-stromal tumour section apply.

  • Multiple pregnancies or oral contraceptive use are protective
  • BRCA1 germline mutations are closely associated with serous adenocarcinoma
  • Western diet and lifestyle may be a contributing factor

Pathogenesis

Serous adenocarcinoma is an epithelial tumour that is thought to arise from the surface epithelium of the ovary. TP53 loss seems to be an early event in most cases. A pre-malignant disease has not been identified.

Clinical Features

Early stage disease mimics common gastrointestinal symptoms. Late stage disease can present with ascites, bloating or other visceral involvement.

Tumour Features

Macroscopically, serous adenocarcinoma has a range of appearances depending on the grade. Low grade tumours are usually comprised of large solid and cystic components; papillae are visible on the cyst surface. High grade tumours are solid, multinodular and contain areas of haemorrhage and necrosis.

Microscopic

Microscopic appearance is dependant on stage but usually contains a mix of papillary, glandular and solid components. A common finding is psammoma bodies, which are deposits of calcium.

Immunohistochemistry

CK7 is always positive and CK20 is always negative. Mesothelial markers are negative.

Genetics

TP53 is usually mutated (60%) and derangement of its function is thought to be the most important step in the pathogenesis of the disease. It is found in most stages and grades of serous adenocarcinoma. Less aggressive serous tumours (borderline serous tumour and benign serous tumour) usually contain normal TP53.

Staging