A rare case of collision tumor: Massive mucinous cystadenoma and benign mature cystic teratoma arising in the same ovary

Reddy Ravikanth

doi:10.4103/cjhr.cjhr_20_17

CASE REPORT

Year : 2017 | Volume : 4 | Issue : 3 | Page : 201-203

A rare case of collision tumor: Massive mucinous cystadenoma and benign mature cystic teratoma arising in the same ovary

Reddy Ravikanth
Department of Radiology, St. John's Medical College, Bengaluru, Karnataka, India

Date of Web Publication

13-Jul-2017

Correspondence Address:
Reddy Ravikanth
St. John's Medical College, Bengaluru - 560 034, Karnataka
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/cjhr.cjhr_20_17

Abstract

Collision tumor means the coexistence of two adjacent, but histologically distinct tumors without histologic admixture in the same tissue and is rare incidence involving the ovary. There are instances of collision tumors consisting of teratoma with serous cystadenocarcinoma, mucinous cystadenocarcinoma, and/or granulosa cell tumor. The possible existence of an ovarian collision tumor should carefully be examined pre- and post-operatively and histologically, so as to avoid misdiagnosis of a possible malignancy. We describe the findings in a histopathologically proven case of a massive mucinous cystadenoma and benign mature cystic teratoma arising in the same ovary.

Keywords: Benign mature cystic teratoma, collision tumor, histopathology, imaging, mucinous cystadenoma, same ovary

How to cite this article:
Ravikanth R. A rare case of collision tumor: Massive mucinous cystadenoma and benign mature cystic teratoma arising in the same ovary. CHRISMED J Health Res 2017;4:201-3

How to cite this URL:
Ravikanth R. A rare case of collision tumor: Massive mucinous cystadenoma and benign mature cystic teratoma arising in the same ovary. CHRISMED J Health Res [serial online] 2017 [cited 2022 Dec 8];4:201-3. Available from: https://www.cjhr.org/text.asp?2017/4/3/201/210485

Introduction

Collision tumor is coexistence of two distinct tumors in the same organ without any histological intermixing at the interface. Collision tumors have been described in various organs including esophagus, stomach, liver, bone, kidney, brain, and lung. Such tumors involving the ovary are rare.^[1] Teratoma is one of the most common components of collision combination in the ovary. Ovarian teratomas are the most common germ cell neoplasms and the most common excised ovarian neoplasms. The most common of these tumors are the benign mature cystic teratomas (also known as dermoid cysts), representing 12%–15% of the ovarian tumors.^[2] Mucinous cystadenoma of the ovary comprises approximately 80% of mucinous ovarian tumors and 20%–25% of all benign ovarian tumors. Mucinous cystadenomas generally tend to be larger than serous cystadenomas at presentation. Bilaterality is rare (2%–5%).^[3] Mural calcification is more common than serous tumors. We present the findings in a rare case of a nonchild-bearing female who was hospitalized for the removal of a large cystic mass, probably arising from the right ovary. Histopathology confirmed a collision tumor of a mucinous cystadenoma and a mature, solid teratoma in the right ovary.

Case Report

A 27-year-old unmarried female presented with complaints of right-sided pelvic pain and a sensation of fullness in her lower abdomen. On examination, cystic mass measuring 20 cm × 10 cm with smooth surfaces was palpable in the hypogastrium, umbilical and right lumbar and iliac fossa regions. A subsequent pelvic sonography showed a complex, right ovarian cyst measuring approximately 23 cm × 13 cm × 21 cm; her carbohydrate antigen (CA) 125 level was 18.1 U/mL (normal, 0–25 U/mL) and CA19.9 was 7.4 (normal range 0–37 U/mL, at our hospital). The structure appeared cystic, anechoic with several septations and debris and appeared to be a part of the right ovary. Contrast-enhanced computed tomography (CT) showed a large intraperitoneal multiloculated cystic lesion having thick enhancing septations, with some of the locules having fl uid of increased density. Another encapsulated predominantly fat containing lesion measuring 3.5 cm × 5.2 cm with a calcifi c focus was seen posterior to the multiloculated lesion [Figure 1].

Figure 1: Coronal CECT image of the abdomen and pelvis showing a multiloculated cystic lesion (star) arising from the right ovary with an adnexal fat containing lesion (arrow)

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Both the above lesions were noted to derive vascular supply from the right ovarian vessels. A right salpingo-oophorectomy was performed. Intraoperative findings were a right ovarian multiloculated cyst of 23 cm × 15 cm × 25 cm with mucinous material admixed with yellow cheesy material and hair shafts. Histopathological examination showed right mucinous cystadenoma and benign mature cystic teratoma of the right ovary [Figure 2].

Figure 2: (a) Mucinous cyst of the right ovary lined by monolayered cuboidal epithelium (H and E, x40). (b) Dermoid cyst of the right ovary with squamous epithelium and keratinization (H and E, x100)

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Discussion

Collision tumor represents the coexistence of two adjacent, but histologically distinct tumors with no histologic admixture at the interface. Ovarian collision tumors are rare. They are most commonly composed of teratoma and cystadenoma or cystadenocarcinoma.^[4] However, other histologic combinations have also been reported (e.g., teratoma and granulosa cell tumor, cystadenocarcinoma, and sarcoma). When an ovarian tumor demonstrates imaging findings that cannot be put under one histologic type, a collision tumor should be considered.^[5]

Benign mucinous cystadenoma is a tumor that manifests as a multilocular cystic mass that has a thin regular wall and septa or that contains liquids of different attenuation or signal intensity but has no endocystic or exocystic vegetation.^[6] Mucinous cystadenomas tend to be larger than serous cystadenomas at presentation.

Mature teratoma is the most common benign ovarian tumor in women aged <45 years. There is usually a raised protuberance projecting into the cyst cavity known as the Rokitansky nodule. Most of the hair typically arises from this protuberance.^[7] When bone or teeth are present, they tend to be located within this nodule; ultrasonography findings in mature cystic teratomas vary from a cystic lesion with a densely echogenic tubercle (Rokitansky nodule) projecting into the cyst lumen, to a diffusely or partially echogenic mass with the echogenic area usually demonstrating sound attenuation owing to sebaceous material and hair within the cyst cavity, to multiple thin, echogenic bands caused by hair in the cyst cavity.^[8] At CT, fat attenuation within a cyst, with or without calcification in the wall, is diagnostic for mature cystic teratoma.^[9]

However, the presence of an equivocal intermediate transitional zone between the tumors may make it more difficult to differentiate between a collision tumor and a true mixed tumor.^[10] The histological combination of teratoma and mucinous cystadenoma is the most common form of collision tumors in the ovary.^[11]

Conclusion

Collision tumors involving ovaries are extremely rare entities, but even rarer is the coexistence with other benign ovarian tumors. Multiloculated cysts have to be extensively examined radiologically and histopathologically, not to miss any component which might have a bearing on prognosis of the patient.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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