|Year : 2015 | Volume
| Issue : 4 | Page : 1024
Squamous cell carcinoma arising in mature cystic teratoma with sigmoid invasion
Pooja Srivastava, Leelavathi Dawson, Ashish Kumar Mandal
Department of Pathology, VMMC and Safdarjung Hospital, New Delhi, India
|Date of Web Publication||15-Feb-2016|
270, Hauz Rani, Malviya Nagar, New Delhi - 110 017
Source of Support: None, Conflict of Interest: None
Malignant transformation in a mature cystic teratoma (MCT) is rare occurring in 1.8% out of 8000 cases of MCT. The most common histological types are squamous cell carcinoma (SCC) followed by adenocarcinoma and melanoma. Clinically, these tumors are usually asymptomatic but may be discovered accidentally during gynecologic examination due to mass effect. We present cytology and histology correlation of a rare case of SCC arising in a dermoid cyst with metastasis to sigmoid.
Keywords: Malignant transformation, mature cystic teratoma, squamous cell carcinoma
|How to cite this article:|
Srivastava P, Dawson L, Mandal AK. Squamous cell carcinoma arising in mature cystic teratoma with sigmoid invasion
. J Can Res Ther 2015;11:1024
| > Introduction|| |
Mature cystic teratoma (MCT) is a common benign adnexal tumor in females, accounting for 20% of all ovarian tumors and 95% of all ovarian teratomas. However, occurrence of malignant transformation in an MCT is rare with a reported incidence of around 1.8% among 8000 cases of MCT.  Approximately, 75% of malignancies arising in cystic teratomas are invasive or rarely in situ squamous cell carcinomas (SCCs), followed by adenocarcinoma (7%) and sarcoma (7%).  MCT more commonly occurs in premenopausal women and are usually unilateral. But when discovered in women above 50 years of age, the likelihood of malignant transformation of any of the components is very strong. We present a case of malignant transformation in MCT with metastasis to sigmoid which was suspected on frozen sections and later confirmed by routine histopathology.
| > Case report|| |
A 60-year-old postmenopausal female presented with complaints of frequent pain in the abdomen for past 2 years. On abdomen examination, a mass was felt arising from the pelvis. CA-125 level was 51.3 U/ml (reference range 0.00-35.00 U/ml) and carcinoembryonic antigen level was 24.7 U/ml (reference range 0.00-5.00 U/ml). Ultrasonography (USG) and contrast-enhanced computerized tomography abdomen were done which revealed a large cystic mass in the pelvis measuring about 10 cm × 10 cm × 4 cm. The cyst showed fat fluid levels with heterogeneously enhancing solid component at the base of lesion suggestive of ovarian dermoid. She underwent exploratory laparotomy, and the ovarian mass peroperatively was found adhered to the sigmoid colon which was sent for frozen section. Biopsy from the deposit on sigmoid was also sent for histopathological examination. Cystic mass measuring 14 cm × 9 cm × 4 cm was received. Cut surface shows unilocular cyst with solid areas. The cyst was filled with pultaceous material and plug of hair. Frozen sections along with crush smears prepared, showed the presence of malignant looking squamous cells along with the presence of benign structures derived from three germ layers [Figure 1]. Routine histopathological examination sections from the cyst wall showed mature squamous epithelium [Figure 2], glial tissue and fat. Sections from solid area showed nests of tumor cells having clear to eosinophilic cytoplasm, vesicular nucleus and frequent mitosis [Figure 3]. Tumor cells show intracellular and extracellular keratin along with extensive areas of necrosis. Pattern of infiltration was gamma mode [Figure 4]. Biopsy from the sigmoid deposit also showed the presence of clusters of malignant squamous epithelial cells with atypical mitotic figures. Diagnosis of moderately differentiated SCC arising in MCT with infiltration of the wall of the sigmoid colon was given. Patient was given first cycle of chemotherapy after which she was lost to follow-up.
|Figure 1: Smear showing presence of malignant squamous cells with giant cells and hair (H and E, ×10)|
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|Figure 2: Microphotograph showing mature squamous epithelium and adipose tissue that are components of teratoma (H and E, ×10)|
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|Figure 3: Microphotograph showing malignant squamous cells with the presence of keratin (H and E, ×10)|
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|Figure 4: Microphotograph showing islands of malignant squamous cells present in fibrocollagenous stroma (H and E, ×10; gamma mode)|
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| > Discussion|| |
Squamous cell carcinoma arising in MCT is extremely rare occurring in 1-2% of cases. The rarity of this condition is generally true for all age groups but in perimenopausal women and older women as in this case, chances of any of this component becoming malignant is higher.  Though the reason for this is not clear, it is postulated that long-term presence of MCT and squamous metaplasia of the columnar epithelium may be followed by malignant change.  Most of the malignant change in MCT recorded in literature is predominantly SCC accounting for 75% cases. Preoperative diagnosis is difficult because of lack of specific symptoms and signs to suggest malignancy.  The most common symptoms being abdominal pain followed by abdominal or pelvic mass. In some other cases various symptoms due to invasion of nearby organs are the presenting complaints such as gastrointestinal symptoms of constipation, diarrhea, rectal bleeding or urinary frequency. SCC arising in MCT has been usually observed in relatively older patients of around 58.2 years of age as compared to 37.5 years in MCT.  Tumor size has also been noted to predict malignancy, mean size of SCC arising in MCT has been mentioned to be 15.23 cm as compared to 4.82 cm in MCT as was noted in our case where the tumor diameter was around 14.0 cm. Another study reported that a tumor diameter of 9.9 cm was 86% sensitive for malignancy. 
Preoperative diagnosis of MCT of ovary is relatively easy due to the radiological detection of bony tissues, cartilage and teeth. However, preoperative diagnosis of malignant transformation is very difficult because this tumor cannot be readily differentiated from uncomplicated MCT or other ovarian tumors.
The malignant component of this tumor sometimes exists in only part of the lesion causing difficulty in suspecting the malignancy on gross; hence every case of MCT should be carefully grossed. In our case, the malignant component presented as a solid area with hemorrhage and necrosis. It can be seen microscopically as nests of squamous cells infiltrating in the stroma. Mode of infiltration of the tumor cell in the stroma was first described by Kikkawa et al. in the year 1997 into three patterns.  In alpha mode, the tumor cells invade the stroma expansively with a well-defined border between the tumor and the stroma while in gamma mode the tumor cells diffusely invade the stroma without a clear border. Beta mode shows intermediate features between alpha and gamma mode.  They studied 32 cases of SCC arising in MCT and noticed that 11 patients with alpha mode remained alive without disease, whereas 12 patients showed beta mode out of which four of them died within 20 months. Nine patients showed gamma mode all of them died within 19 months. Thus, their analysis showed a significant difference among these three groups, suggesting that mode of infiltration is a good indicator of prognosis. Our patient had gamma mode of infiltration along with metastatic deposit to the sigmoid colon. These tumors are known to spread by direct local invasion and peritoneal seeding, and this may probably explain the spread to sigmoid colon in this patient. These metastatic deposits may be missed at the time of presentation both on USG and intraoperative procedure.
Old age, large tumor size and solid portion in MCT seem to predict the malignant transformation of MCT and warrant the need for a frozen section. Suspicion of malignancy on frozen section can serve as a guide to the surgeon for staging laparotomy in place of conservative surgery. Mode of the infiltration needs to be incorporated in the reporting as a predictive index for survival. Other factors that carry a poor prognosis are International Federation of Gynecology and Obstetrics stage, cyst wall invasion, rupture, tumor dissemination, adhesion, grade, vascular invasion and histological subtype.
| > References|| |
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]