CASE 10273 Published on 03.12.2012

Ovarian mucinous cystadenoma: CT and MR imaging findings

Section

Genital (female) imaging

Case Type

Clinical Cases

Authors

Aikaterini Ntoulia, Athina C. Tsili, Maria I. Argyropoulou, Konstantinos Tsampoulas

Department of Clinical Radiology
University Hospital of Ioannina, Greece.

University Hospital of Ioannina, Department of Clinical Radiology; Leoforos S. Niarchou, 45500, Ioannina, Greece; Email:a_tsili@yahoo.gr
Patient

42 years, female

Categories
Area of Interest Genital / Reproductive system female ; Imaging Technique PACS, CT, MR, MR-Diffusion/Perfusion
Clinical History
A 42-year-old female patient was referred for a sonographically detected multicystic adnexal mass. Laboratory analysis revealed elevated serum CA 19-9 levels and moderate haematocrit decrease. CT of the abdomen and MR imaging examination of the pelvis followed.
Imaging Findings
Multidetector CT revealed the presence of a multilocular cystic mass originating from the left adnexa (Figure 1). The dimensions of the lesion were 13x12x8.5 cm. The mass had a smooth contour and multiple, thin regular internal septa, some containing small calcifications. The lesion contained parts of water density and others, with a mean CT density of 45 HU. Contrast-enhanced CT demonstrated only wall and septa enhancement, detected with a thickness less than 3 mm. Neither lymphadenopathy nor ascites was revealed.

MR imaging confirmed the presence of a multicystic pelvic mass, consisting of loculi, with a signal intensity similar to that of water and others, hyperintense on both T1 and T2-weighted images, the latter suggestive of fluid with variable viscosity (Figure 2). No areas of restricted diffusion within the mass were revealed.
Imaging findings were suggestive of the presence of mucinous ovarian cystadenoma, which was confirmed histologically (Figure 3), following cystectomy.
Discussion
Background:
Epithelial ovarian neoplasms represent 60% of all ovarian tumours and are classified as benign (60%), borderline (5%) and malignant (35%), based on histologic characteristics and clinical behavior. The two commonest subtypes are serous and mucinous tumours, with a frequency of 40% and 20%, respectively [1-6].
Ovarian mucinous cystadenomas account for 20% of benign tumours [5]. Histologically, they are lined by mucinous epithelium and contain gelatinous material or fluid of various viscosities [5, 6].
Imaging Perspective:
Determining the subtype and suspicion of malignancy of an adnexal mass on the basis of imaging features represents a diagnostic challenge [1-3]. The CT diagnosis of mucinous cystadenoma should be suggested in the presence of a large multicystic adnexal mass, with multiple internal septa, not enhancing after contrast material administration, except perhaps the wall or septa, which are less than 3 mm in thickness and no endocystic or exocystic vegetations. The tumour often contains hyperdense parts, the latter suggestive of mucin content [7-9]. The presence of a multilocular cystic mass, with thin wall or septa, less than 3 mm in thickness, no evidence of internal solid components or invasive disease, containing hyperintense parts on both T1 and T2-weighted sequences, due to the presence of mucin should also suggest the diagnosis of mucinous cystadenoma on MR imaging. Differential diagnosis from serous cystadenoma may not always be possible, although a unilocular or multilocular adnexal tumor, filled with serous fluid, of homogeneous CT density or MR signal similar to that of water, not enhancing, except the wall or septa, of less than 3 mm in thickness is more compatible with the diagnosis of a serous cystadenoma [7-9].
Ovarian malignancy on the other hand is strongly suggested in the presence of a thick, irregular wall, of thickness more than 3 mm, thick, irregular septa, papillary projections and solid, enhancing tissue, with presence of necrosis. Ancillary findings of pelvic organ invasion, lymphadenopathy, ascites and peritoneal metastases increase the diagnostic confidence of malignancy [1-3, 7-9].
Borderline ovarian tumours are often difficult to characterize on imaging, because of their close resemblance to benign tumours. Outwater et al suggested the diagnosis of borderline malignancy in the presence of abundant papillary projections in a young woman [10]. Papillary projections are often absent in benign cystadenomas, but when present they are usually few in number and small in size.
Differential Diagnosis List
Ovarian mucinous cystadenoma
Serous cystadenoma
Mucinous borderline tumour
Serous cystadenocarcinoma
Mucinous cystadenocarcinoma
Final Diagnosis
Ovarian mucinous cystadenoma
Case information
URL: https://www.eurorad.org/case/10273
DOI: 10.1594/EURORAD/CASE.10273
ISSN: 1563-4086