"Sack of Marbles" Appearance of a Scalp Teratoma.

Abstract

HomeRadiologyVol. 307, No. 5 PreviousNext Reviews and CommentaryFree AccessImages in Radiology“Sack of Marbles” Appearance of a Scalp TeratomaSumit Thakar , Pavan VasoyaSumit Thakar , Pavan VasoyaAuthor AffiliationsFrom the Department of Neurosurgery, Sri Sathya Sai Institute of Higher Medical Sciences, ITPL Rd, EPIP Area, Whitefield, Bangalore 560066, India.Address correspondence to S.T. (email: [email protected]).Sumit Thakar Pavan VasoyaPublished Online:May 30 2023https://doi.org/10.1148/radiol.230033MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In A 52-year-old woman presented with a painless, gradually enlarging scalp swelling that had been present since childhood. At examination, there was a 15 × 10 × 12–cm mass in the parieto-occipital region. MRI scan showed a large cystic lesion in the subgaleal plane of the scalp. It was hypointense with T1-weighted images and hyperintense with T2-weighted images and contained multiple nodules of varying sizes floating in the cyst, giving it a “sack of marbles” appearance (Figure). The nodules had thick outer rims that were iso- to hyperintense with T1-weighted sequences and hypointense with T2-weighted sequences and thin inner cores that were hypointense with T1-weighted sequences and hyperintense with T2-weighted sequences. The nodules demonstrated restricted diffusion (Figure) and had low apparent diffusion coefficient values. After completing surgical excision, the cyst was found to contain sebum-like material, hard spherules, and multiple strands of hair (Figure). Histopathologic examination confirmed the diagnosis of a mature cystic teratoma, with elements from all three germ layers. There was no recurrence after 6 months of follow-up.Images in a 52-year-old woman presenting with a scalp mass show a large cystic lesion in the subgaleal plane of the scalp with a “sack of marbles” appearance. (A) Sagittal unenhanced T1-weighted MRI scan shows a smooth-walled hypointense cyst with multiple spherical nodules that had isointense to hyperintense rims and thin hypointense cores. (B) Diffusion MRI scan shows the nodules demonstrating restricted diffusion. (C) Photograph of the gross specimen shows a sebum-like material within the cyst, hard spherical nodules, and strands of hair.Download as PowerPointOpen in Image Viewer Mature cystic teratomas are commonly found in the gonadal tissues and in the head and neck region. In the head, they have a predilection for the orbit and scalp. The “marbles” are spherical aggregates of keratin, fat, sebaceous material, fibrin, and hair floating within the fluid matrix of the cyst. Though uncommon, the “sack of marbles” sign is considered pathognomonic of mature cystic teratomas in the head and neck (1–3).Disclosures of conflicts of interest: S.T. No relevant relationships. P.V. No relevant relationships.