Table of Contents  

Al-Zuheiri and Fwakhrji: Ovarian mucinous cystadenoma arising from a mature cystic teratoma – a case report


Histologically distinct tumours sometimes coexist in the same organ and are described as collision tumours. Collision tumours involving the ovaries are infrequently reported. In this case we report the coexistence of a mucinous cystadenoma with a mature cystic teratoma of the ovary, the tumour occupying the whole pelvis and abdomen and weighing 10.35 kg.


Mature cystic teratomas of the ovary, commonly called dermoid cysts, are among the most common benign neoplasms of the ovary and are derived from germ cells. They most commonly occur in young patients, usually during the reproductive years.1 Ovarian mucinous cystadenoma is a benign tumour that arises from the surface epithelium of the ovary. It is a multilocular cyst with smooth outer and inner surface, and tends to be large. Mucinous tumours constitute 15% of all ovarian tumours.2,3 Mucinous cystadenomas are common in those aged 30–50 years.4

The coexistence of two adjacent but histologically distinct tumours without histological admixture in the same tissue or organ is rare condition called a collision tumour. The association of a mucinous cystadenoma with a mature cystic teratoma is infrequently reported. Here we report the case of a large ovarian mucinous cystadenoma associated with a mature cystic teratoma weighing 10.35 kg.

Case presentation

A 26-year-old unmarried Arabian woman presented to the gynaecological outpatient clinic in Saqr Hospital, Ras al-Khaimah, United Arab Emirates, with abdominal distension over a 1.5-year period associated with loss of appetite. Her menstrual cycles were regular and her weight on presentation was 59 kg. During the physical examination, the abdomen looked massively distended with an abdominal mass reaching the xiphisternum. Ultrasonography revealed a multiseptated cystic mass occupying almost the whole pelvis and abdomen (37 × 23 cm), displacing the uterus and causing bilateral hydronephrosis that was more severe in the right kidney, which showed hydroureter. Other abdominal organs were normal; no free fluid collection could be seen.

Magnetic resonance imaging revealed a 33 × 20 cm benign, multilocular cystic mass with heterogeneous signal intensity, most likely of mucinous origin. This mass affected both kidneys, but predominantly the right, which showed severe hydronephrosis.

Tumour markers were as follows: CA-125 70 units/ml (normally 0–35 units/ml); carcinoembryonic antigen 7.60 mg/ml (normally 0.0–4.7 mg/ml); alpha-fetoprotein 3.71 mg/ml (normally 0.0–7.02 mg/ml); and human chorionic gonadotropin 0.1 miu/ml (normally 0.0–3.00 miu/ml).

The patient was admitted for exploratory laparotomy. A midline incision extending 5 cm above the umbilicus exposed a huge mass extending from the right ovary, filling both flanks and pushing the diaphragm upwards; the uterus was normal in size but pushed to left side and the left ovary was normal in shape and size. A peritoneal wash with normal saline was performed and the aspirated fluid sent for cytological examination. After packing the abdomen, the cyst was aspirated to reduce its size so that it can be removed through the abdominal incision; approximately 6 l of viscous fluid was aspirated before the cyst could be delivered from the abdominal incision.

Right salpingo-oophorectomy was performed as no apparently normal residual ovarian tissue was seen because of the huge size of the cyst. The cyst’s net weight together with the fluid aspirated was 10.35 kg. The postoperative period was uneventful and the patient was discharged after 3 days, in good general condition.

Histopathology showed a multiloculated mucinous cystadenoma (28 cm in diameter) (Figures 1 and 2), filled with mucin and lined by mucinous epithelium, arising from a mature cystic teratoma (6 cm in diameter) (Figure 3), filled with greasy material and hair shafts, and lined by stratified squamous epithelium and skin appendages.


Collision tumour – dermoid cyst (right) and mucinous cyst (left).


Mucinous cystadenoma – mucinous epithelium.


Mature cystic teratoma of ovary, ectodermal structure of skin and appendages.


Cytology of the viscous fluid aspirated from the cystic lesion was not specific, showing scattered benign epithelial cells, macrophages and naked nuclei against a background of amorphous mucinous eosinophilic material with no atypical or malignant cells identified. The peritoneal wash revealed no malignant cells.


Mature cystic teratomas of the ovary are among the most common benign neoplasms of the ovary derived from germ cells, and are commonly seen in young women of reproductive age;1 the histology of these tumours reveals tissues originating from the ectoderm, mesoderm and endoderm. Mucinous tumours are multiloculated cysts lined by epithelium resembling that of the endocervix. Mucinous cystadenomas account for 8–10% of all epithelial ovarian tumours and 15% of all ovarian tumours;2,3 they are bilateral in 10% of cases.5

The coexistence of two distinct tumours in the same organ without any histological intermixing is called a collision tumour.6 Collision tumours have been reported in various organs (e.g. the gastrointestinal tract, lung, skin, adrenal glands, central nervous system, lymph nodes, uterus, etc.) but are relatively rare in the ovary. The most common histological combination of collision tumour in the ovary is the coexistence of a teratoma with mucinous tumours.7,8

Various hypotheses have been suggested regarding the formation of collision tumours. The first hypothesis is that the coexistence of two primary tumours in the same tissue is the result of a chance accidental meeting. The second hypothesis proposed is that the presence of the first tumour creates changes in the microenvironment, engendering the development of the second primary tumour or the seeding of metastatic tumour cells. The third theory proposes that each primary tumour has its origins in a common stem cell.9

We present this case in view of the large cyst removed, which occupied the whole abdomen and pelvis, weighed 10.3 kg and caused pressure symptoms on the bowel and renal system. To the best of our knowledge this is the first reported case of such a large collision tumour of the ovary.



Templeman CL, Fallat ME, Lam AM, Perlman SE, Hertweck SP, O’Connor DM. Managing mature cystic teratomas of the ovary. Obstet Gynecol Surv 2000; 55:738–45.


Vizza E, Galati GM, Corrado G, Atlante M, Infante C, Sbiroli C. Voluminous mucinous cystadenoma of the ovary in a 13-year-old girl. J Pediatr Adolesc Gynecol 2005; 18:419–22.


Mittal S, Gupta N, Sharma A, Dadhwal V. Laparoscopic management of a large recurrent benign mucinous cystadenoma of the ovary. Arch Gynecol Obstet 2008; 277:379–80.


Ioffe OB, Simsir A, Silverberg SG. Pathology. In: Berek JS, Hacker NF (eds.) Practical Gynaecologic Oncology. Philadelphia: Lippincott Williams & Wilkins Company; 2000. pp. 213–14.


Alobaid AS. Mucinous cystadenoma of the ovary in a 12-year-old girl. Saudi Med J 2008; 29:126–8.


Bige O, Demir A, Koyuncuoglu M, et al. Collision tumor: serous cystadenocarci-noma and dermoid cyst in the same ovary. Arch Gynecol Obstet 2009; 279:767–70.


Kim SH, Kim YJ, Park BK, et al. Collision tumors of the ovary associated with teratoma: clues to the correct preoperative diagnosis. J Comput Assist Tomogr 1999; 23:929–33.


Tang P, Soukkary S, Kahn E. Mature cystic teratoma of the ovary associated with complete colonic wall and mucinous cystadenoma. Ann Clin Lab Sci 2003; 33:465–70.


Brandwein-Gensler M, Urken M, Wang B. Collision tumor of the thyroid: a case report of metastatic liposarcoma plus papillary thyroid carcinoma. Head Neck 2004; 26:637–41.

Add comment 

Home  Editorial Board  Search  Current Issue  Archive Issues  Announcements  Aims & Scope  About the Journal  How to Submit  Contact Us
Find out how to become a part of the HMJ  |   CLICK HERE >>
© Copyright 2012 - 2013 HMJ - HAMDAN Medical Journal. All Rights Reserved         Website Developed By Cedar Solutions INDIA