[P-02] Two types of malignant transformation in bilateral ovarian mature cystic teratoma: a very rare case

Eduardo Nel C. Oira, Joseph Antoine F. Chatto and Emelisa G. Almocera

Department of Pathology, Governor Celestino Gallares Memorial Hospital, Tagbilaran City, Bohol, Philippines

Background: Malignant transformation (MT) arising from the mature cystic teratoma (MCT) is a rare occurrence, comprising about 1% – 3% in all documented MCTs. Majority of MT cases are squamous cell carcinoma, followed by adenocarcinoma, then neuroendocrine neoplasm. Bilateral ovarian MCT with both MTs of different types is extremely rare. This is the first documented case in the Philippines.

Case Presentation: A 54-year-old female presented with three-month gradually enlarging abdomen. Initial preoperative diagnoses were right ovarian new growth and left dermoid cyst. Patient underwent total abdominal hysterectomy with bilateral salpingo-oophorectomy that revealed bilateral ovoid, solid cystic ovarian masses containing hair and sebum. Microscopically, two distinct MTs were noted in both ovarian MCT: well-differentiated neuroendocrine tumour (NET) in the right and well-differentiated squamous cell carcinoma in the left. The NET showed trabecular growth pattern and expressed synaptophysin and CD56.

Discussion and Conclusion: Malignant transformation of MCTs is indeed a very rare phenomenon, mostly diagnosed postoperatively. Hence, thorough morphologic studies under light microscopy supported by immunohistochemistry are very significant for a correct diagnosis. The core management is surgical excision. Due to its uniqueness, further data gathering is needed to better understand the process of MT in bilateral ovarian MCT.