Seromucinous carcinoma of ovary - A rare entity

Introduction

In the revised World Health Organisation classification of Tumours of the Female Reproductive organs, seromucinous neoplasms are a new category of ovarian epithelial tumor which are believed to have an association with endometriosis.1 In older classification these tumors follow a wide range of course ranging from benign to malignant included seromucinous cystadenoma/cystadenofibroma, seromucinous borderline tumor/atypical proliferative seromucinous tumor and seromucinous carcinoma. These tumors histomorphologically are a mixture of serous and endocervical type with ocassionally having foci of clear cell, squamous, transitional and endometroid epithelium.2 Ovarian seromucinous carcinoma was removed as separate entity and renamed as ovarian endometrioid carcinoma with mucinous differentiation according to 2020 World Health Organisation classification of Female Genital Tumors.3 Seromucinous carcinoma does not exhibit a distinct genotype or immunophenotype and its morphological diagnosis is also not very reliable.4 The molecular features of seromucinous carcinoma overlaps with endometrioid and low grade serous carcinomas.4 Serous, mucinous, clear cell, endometrioid, transitional, and squamous cell carcinoma are classified under epithelial ovarian neoplasm.3 It is most common in elderly patient, mean age group is around 48 years.5 The most common complain of patient is abdominal distension.5 The serum concentration of CA125 and CA19-9 is elevated in most of the patients.5 ER, PR, CA-125 and mesothelin are various markers of mullerian epithelium which is also expressed by seromucinous carcinoma.3 Ovarian seromucinous carcinoma also expresses PAX-8 strongly which was similar to serous tumors but different from mucinous tumors.3 Seromucinous component shows strong expression for CK7 and no expression for CK20 and CDX2.6 Endometrioid carcinoma component had higher immunoreactivity for ER and PR as compared to Seromucinous component.6 The prognosis of seromucinous carcinoma was excellent as most of this tumors belongs to Stage I disease.6

Case Report

A 30-year-old female presented with complain of lower abdominal pain which was more prominent on left side for the past 30 days. It was gradual in onset, progressive in nature, moderate to severe in intensity. She also complained of abdominal distension for past 20 days which was gradual in onset. The patient had no history of fever, cough, yellowish discolouration of eyes, no puffiness of face and swelling over legs. The bowel and bladder habits were normal, but she complained of irregular menstrual cycle and heavy menstrual bleed for past 3 months. She was extremely weak with loss of appetite.

Gross

A gross examination of resected specimen was carried out. Left tubo-ovarian mass measures 12.5x11.3x6.9 cm, outer surface shows multiple nodular growth alongwith areas of congestion and specks of haemorrhage.(Figure 1) Cut section of specimen shows necrosis, papillary areas, solid, cystic and nodular areas along with few loculated areas with solid gel like material.(Figure 2)

Figure 1

Resected specimen of left tubo-ovarian mass showing multiple nodular areas

Figure 2

Cut section of specimen shows necrosis, papillary areas, solid, cystic and nodular areas alongwith few loculated areas with solid gel like material

Microscopy

Microscopic examination of section obtained from left sided tubo-ovarian mass showed both serous and mucinous components embedded in a background of fibrocollagenous stroma.(Figure 3) Psammoma bodies were seen in serous component along with areas of necrosis, haemorrhage and few dilated and congested blood vessels. As the sections showed clear cut demarcation of serous and mucinous components, the histopathological picture was clearly that of a sero-mucinous ovarian carcinoma and no other differential diagnoses were made.

Figure 3

A,B): Section shows serous and mucinous component. Serous component has psammoma bodies. Background shows fibrocollagenous stroma. Few dilated and congested blood vessels are also seen

Immunohistochemical marker CK7, CK20 and CDX2 were applied. Positive reactivity for CK7 and negative reactivity for CK20 and CDX2 was seen on IHC examination.(Figure 4) Few IHC markers and Molecular studies could not be carried out because of poor financial status of the patient and non-availability of resources.

Figure 4

A): Immunohistochemistry shows positive reactivity for CK7; B): Immunohistochemistry showing negative reactivity for CK20 and CDX2

Thus, a final diagnosis of Seromucinous carcinoma of ovary was made on the basis of gross, microscopic examination and immunohistochemical studies.

Discussion

Ovarian tumors are classified as Germ cell, Epihelial/surface, Sex cord - Stromal tumor; out of which epithelial ovarian tumors are most common and accounts for almost 70% cases. The epithelial ovarian tumors are further subcategorized as Brenner, Serous, Mucinous, Endomrtrioid and Clear cell. However Germ cell tumors accounts for 10% of cases and it includes Dysgerminoma, Teratoma, Embryonal, Yolk sac and Choriocarcionma. Seromucinous tumor is composed of serous-type cells and endocervical-type mucinous epithelium.7 In the 2014 WHO classification, Ovarian seromucinous tumors were introduced as one of the seven types of ovarian epithelial tumors. Ovarian seromucinous carcinoma was removed as separate entity and renamed as ovarian endometrioid carcinoma with mucinous differentiation according to 2020 World Health Organisation classification of Female Genital Tumors.3 Benign and malignant categories of seromucinous tumors do exists although most of them are classified under borderline category.8 Different categories of seromucinous tumors shows common characteristics features:- (i) (20-40%) shows involvement of both the ovaries, (ii) no gastrointestinal differentiation, as evidenced by mixture of goblet cells and/or paneth cells and, (iii) (30-70%) shows association with endometriosis.8 The clinical and molecular features of seromucinous tumors demonstrates close relationship with endometriosis similar to that of endometrioid and clear cell tumors.7 Seromucinous carcinoma is most common in elderly patient (>45 years).5 The most common in early stages of ovarian cancer are lower abdominal pain and abdominal distension.9 CA125, also referred as Carbohydrate Antigen 125 is a high molecular weight mucinous glycoprotein found on surface of ovarian cancer cells. This antigen is then shed and quantified in serum samples of ovarian cancer patients.10 Seromucinous tumors shows strong expression of ER(100%), PR(67%), CA125(92%), weak expression of WT1(8%) and no expression of CK20 and CDX2 on immunohistochemical profile.7 The main management of ovarian tumor is its removal by surgery. In terms of practicality and safety in comparison to laproscopy, laprotomy is preferred.9

Post surgery the patient is doing well and there was decline in levels of CA125 and CEA. No post-operative chemotherapy or radiotherapy is required for the patient.

Conclusion

This is a very rare case of Seromucinous Carcinoma of ovary in a young female. Seromucinous Carcinoma shows strong expression for CK7 and no expression for CK20 and CDX2 on immunohistochemical profile. Owing to its rarity the case is being presented here.

Source of Funding

None.

Conflict of Interest

None.