Iceberg (Tip of the Iceberg) Sign

Searching for pelvic masses with an ultrasound probe can be a difficult task; shadowing from bowel gas may obscure masses and some masses may obscure themselves. This fact is borne out in Paul Guttman’s 1977 description ¹ of benign cystic ovarian teratomas that showed only the ‘tip of the iceberg’ ¹ ! He reported 23 surgically proven cases from Stanford University. ‘[T]he consistent, diagnostic feature was the presence of a complex mass with hyperechoic zones that produced acoustic shadowing of the far wall of the mass. In six cases … only the near wall of the mass was recognized, hence the term ‘tip of the iceberg’ sign … [T]he presence of highly reflective and attenuating hair within the sebaceous material … produces [the] characteristic acoustic shadowing’ ¹ (Figure 1). He stressed the importance of not confusing this appearance with shadowing due to bowel gas and he discussed steps that could be taken to make the distinction. Today transvaginal ultrasound scanning, computerized tomography and magnetic resonance imaging make the diagnosis of pelvic masses a less hazardous task and pelvic ‘icebergs’ less of a danger. Figure 1 ‘Midline sagittal sonogram demonstrating the near wall of the dermoid only due to acoustical shadowing (AS) from the hairball (HB), the so-called ‘tip of the iceberg’sign.’ Reprinted from Guttman<xref ref-type="bibr" rid="ref44_1"> ¹ </xref>. In search of the elusive benign cystic ovarian teratoma. <italic>J. Clin. Ultrasound, 1</italic>977, 5, 403–6<bold>.</bold> Copyright 1977 John Wiley <italic>&</italic> Sons. Reprinted by permission of John Wiley & Sons Inc. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003076568/34c29fd5-5662-4e8f-b58c-badd7fa5d724/content/fig44_1_B.jpg"/>