Intestinal adenocarcinoma arising within a mature cystic teratoma
- Areas of skin and sebaceous glands and adipose tissue.
- Predominant areas of irregular crowded moderately differentiated glands in an infiltrative manner in a desmoplastic stroma.
- Glandular and tubular structures are lined by columnar cells with nuclear hyperchromasia, elongation, stratification, abnormal mitoses and clear cytoplasm. Some glands contain central necrosis and inflammatory cells.
- No immature elements were found.
- Apical cytoplasmic and membranous positivity of CK20
- Nuclear positivity of CDX2
- Negative stain of CK7
Points of Pathoclinics:
- Malignant transformation of mature cystic teratomas are uncommon, with less than 1% incidence. The most common malignancy arising from mature cystic teratomas are squamous cell carcinomas, which accounts for approximately 80% of all the cases. The other uncommon malignancies arising from mature cystic teratomas are basal cell carcinomas, sebaceous tumors, malignant melanomas, adenocarcinomas, sarcomas and neuroectodermal tumours. Malignant transformation to adenocarcinomas is very rare. As per the review recent review literature, approximately 12 cases of adenocarcinoma arising from teratomas has been reported.
- An approximately 80% of malignant transformations from mature cystic teratomas have occurred in the women of reproductive age. Malignant transformation of mature cystic teratomas is relative late event, so this may be the reasonable point for removal of mature cystic teratomas, to avoid long term risk of malignant transformation.
- Preoperative diagnosis of malignant transformation of the ovary is difficult. Old age, large tumour size, raised CA125, raised CEA and CA 19.9, postmenopausal status and presence of solid components on MRI are associated with higher chances of malignant transformation of mature cystic teratomas. Elevated serum squamous cell carcinoma (SCC) antigen levels can be helpful for detecting squamous cell carcinoma form mature cystic teratomas. However, no serum tumor marker is specific for diagnosis.
- Macroscopically, variable size of ovarian solid-cystic tumor contains yellow cheesy material, teeth and hair of mature cystic teratoma. Ares of solid necrotic, multiloculated, mucoid surface can be seen. Through sampling is necessary for detection of malignant tumor.
- The most common component of mature cystic teratoma is skin and adnexal structure. Areas of adipose tissue, cartilage, muscle, bone, thyroid, respiratory and gastro-intestinal tissue can be seen. Occasional report indicates the presence of dysplastic glandular epithelium, adjacent to frankly malignant foci. Dysplastic foci are helpful for identifying the primary malignancy arising from teratoma over metastatic adenocarcinoma, later does not have dysplastic foci. Most adenocarcinomas are well to moderately differentiated type, with glandular and tubular structures, lined by columnar cells with nuclear hyperchromasia, elongation, stratification, abnormal mitoses and clear cytoplasm or with cytoplasmic mucin vacuoles. Glands can show cribriform pattern with central necrosis.
- Positive CK20, CDX2 and MUC2 staining and often negative or weak patchy CK7 staining favor primary adenocarcinoma arising in mature cystic teratoma. Some cases may show variable staining for neuroendocrine markers.
- Histopathology alone cannot reliably differentiate primary intestinal adenocarcinomas arising from mature cystic teratomas from metastatic deposits from a primary gastrointestinal cancer and primary mucinous ovarian carcinoma. So, detailed clinical and radiological evaluation is very essential in the evaluation of such cases. Positivity of CDX2, MUC2 and CK20 favors intestinal differentiation. Positivity for CK7 (not focal patchy) and CA125 and negative CK20 and CDX2 suggest a primary ovarian mucinous tumor, but not absolute confirmatory markers. CEA are not helpful in differentials. Distinction between metastatic adenocarcinomas and adenocarcinoma arising from mature cystic teratoma is rest on size and bilaterality of tumor (metastases are generally large and most often bilateral and multi-nodular).
- In most of the cases, the malignancy is confined to the ovary only. Therefore aim is to remove whole tumor with intact ovarian capsule, and prevention of tumor spillage due to tumor rupture. In advanced stage and cases with tumour spillage, adjuvant therapy has been given, however exact guideline of chemo and radiotherapy are not available. Presence of KRAS mutations can be used as a targeted therapy, against the epidermal growth factor receptor, could be effective.
- Prognosis of intestinal adenocarcinomas in mature cystic teratomas is better, as most of the cases are in FIGO state Ia, compared to squamous cell carcinoma arising from mature cystic teratomas. Metastatic disease is associated with poor prognosis. Poor prognostic indicators are large tumor size, raised CA125, CEA and CA19.9 levels, postmenopausal status, presence of solid components, cyst wall invasion, tumor dissemination, ascites, spontaneous or accidental rupture and tumor adhesion.
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