Atypical imaging observations of branchial cleft cysts

Abstract

The aim of the present study was to assess the atypical imaging manifestations of branchial cleft cysts (BCCs) confirmed by pathology. Computerized tomography (CT) or magnetic resonance imaging (MRI) of 17 BCC cases were reviewed. The imaging features, including laterality, location, border, attenuation and internal architecture, were evaluated. All 17 cases were second BCCs, including 5 cases of Bailey type I classification cysts and 12 cases of type II classification cysts. The atypical imaging features included signal and morphological abnormalities. The abnormal signal intensities were caused by intracapsular bleeding (n=2) or solidification of cystic fluid (n=2). Intracystic hemorrhaging revealed homogeneous hyperintensity on T1-weighted image (T1WI) and T2-weighted image (T2WI). Solidification of cystic fluid revealed slightly homogeneous hyperintensity compared with muscle on T1WI and homogeneous hypointensity on T2WI without enhancement. The aberrant morphology mainly presented as thickening of the cystic wall (n=13). Thickened walls of BCCs with ill- (n=5) or well- (n=8) defined borders were observed in 13 patients. In 3 patients, significant enhancement was identified following intravenous gadolinium administration (n=4). When with atypical CT or MRI features are presented, the typical location of BCCs can help in the diagnosis, as it is located at the lateral portion of the neck adjacent to the anterior border of the mandibular angle or sternocleidomastoid muscle. The atypical observations, including variable signals, imply that the cystic content has changed. Thickened walls indicate inflammation or cancerous tendency and patients with ill-defined margins, vascular involvement or lymphadenopathy atelectasis indicate malignant conversion.

Keywords: branchial cleft cysts; computerized tomography; magnetic resonance imaging; neck.

Figure 1

Type II BCC with intracystic hemorrhaging. A left, well-circumscribed mass appeared hyperintense on (A) T1WI and (B) T2WI of the neck. BCC, branchial cleft cysts; T1WI, T1-weighted image; T2WI, T2-weighted image.

Figure 2

Type I BCC with solidification of cystic fluid. A left side, well-circumscribed mass appeared (A) mild hyperintense similar to the muscle on T1WI and (B) hypointense on T2WI. (C) Following the administration of contrast materials, no significant enhancement was observed. BCC, branchial cleft cyst; T1WI, T1-weighted image; T2WI, T2-weighted image.

Figure 3

Type II BCC with infection. (A) A left, ill-defined cystic mass presented with enhanced irregular thickening of the wall on contrast-enhanced T1WI. (B) A small protruding lumen was observed at the lateral wall in coronal planes. BCC, branchial cleft cyst; T1WI, T1-weighted image.

Figure 4

Type II BCC with malignant transformation. (A) A well-defined cystic mass with an intralumenal node was observed on CT scan. (B) In coronal planes, a node located in the inner wall of BCC was observed. BCC, branchial cleft cyst; CT, computerized tomography.

Figure 5

Type II BCC with infection. Axial plain CT scan revealed a left, poorly circumscribed mass with thickened walls in the neck. The density of the sternomastoid muscle and submandibular gland was found to be decreased and the adjacent fat planes were obscured. BCC, branchial cleft cyst; CT, computerized tomography.

Figure 6

Type II BCC with repeated infection. (A) A heterogeneously isointense and hyperintense mass with an irregular border presented in the left side on T1WI. (B) The cystic section of the mass was narrowed and markedly hyperintense on T2WI. BCC, branchial cleft cyst; T1WI, T1-weighted image; T2WI, T2-weighted image.