The shading sign: is it exclusive of endometriomas?

João Lopes Dias, Filipe Veloso Gomes, Rita Lucas, Teresa Margarida Cunha
Abdominal imaging · 2015 · vol. 40(7) , pp. 2566–2572 · doi:10.1007/s00261-015-0465-1 · PMID:26063071 · W1854467527
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⚙ AI-generated summary by claude@2026-06+body, 2026-06-11 ⓘ

This study found the MRI shading sign is not exclusive to endometriomas or endometrioid tumors, with homogenous shading most common in endometriomas and focal shading seen in endometrioid carcinomas.

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⚙ AI-generated deep summary by claude@2026-06, 2026-06-11 · read from full text ⓘ

This retrospective study evaluated whether the MRI “shading sign” is exclusive to ovarian endometriomas or endometrioid tumors by analyzing 340 women with adnexal masses who underwent 1.5/3-T MRI; 51 cases with follow-up imaging and histologic correlation were ultimately included. The shading sign was present in 56 initially, and performance metrics showed overall sensitivity 73%, specificity 93%, positive predictive value 59%, and negative predictive value 96%; when limited to cystic lesions without solid or fat components, specificity increased to 96%. Five shading patterns were described (layering, liquid–liquid level, homogenous, heterogeneous, and focal/multifocal within complex masses) and the paper found no significant correlation between shading pattern and tumor type. The shading sign was found not to be exclusive of endometriomas or endometrioid tumors, and this paper is centrally about endometriosis — it directly tests the specificity of an MRI feature for endometriomas.

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Abstract

Objectives To investigate if the shading sign is an exclusive MRI feature of endometriomas or endometrioid tumors, and to analyze its different patterns.

Methods

Three hundred and fourty six women with adnexal masses who underwent 1.5/3-T MRI were included in this retrospective, board-approved study. The shading sign was found in 56 patients, but five cases were excluded due to lack of imaging follow-up or histological correlation. The final sample included 51 women. The type of tumor and the pattern of shading were recorded for each case.

Results

Thirty endometriomas and five endometrioid carcinomas were found. The remaining 16 cases corresponded to other benign and malignant tumors. The overall sensitivity, specificity, positive predictive value, and negative predictive value were 73%, 93%, 59%, and 96%, respectively. Restricting the analysis to cystic lesions without solid or fat component, sensitivity, specificity, positive predictive value, and negative predictive value were 73%, 96%, 94%, and 80%. Five shading patterns were identified: layering (15.7%), liquid–liquid level (11.8%), homogenous (45.1%), heterogeneous (11.8%), and focal/multifocal shading within a complex mass (19.6%). No significant correlation was found between these patterns and the type of tumor.

Conclusions

The shading sign is not exclusive of endometriomas or endometrioid tumors. Homogenous shading was the most prevalent pattern in endometriomas and half of the cases with focal/multifocal shading within a complex mass were endometrioid carcinomas. Similar content being viewed by others

References

Glastonbury CM (2002) The shading sign. Radiology 224(1):199–201 Siegelman ES, Outwater EK (1999) Tissue characterization in the female pelvis by means of MR imaging. Radiology 212(1):5–18 Gomori JM, Grossman RI, Hackney DB, et al. (1987) Variable appearances of subacute intracranial hematomas on high-field spin-echo MR. AJNR 8:1019–1026 Nishimura K, Togashi K, Itoh K, et al. (1987) Endometrial cysts of the ovary: MR imaging. Radiology 162(2):315–318 Togashi K, Nishimura K, Kimura I, et al. (1991) Endometrial cysts: diagnosis with MR imaging. Radiology 180(1):73–78 Outwater E, Schiebler ML, Owen RS, Schnall MD (1993) Characterization of hemorrhagic adnexal lesions with MR imaging: blinded reader study. Radiology 186(2):489–494 Corwin MT, Gerscovich EO, Lamba R, Wilson M, McGahan JP (2014) Differentiation of ovarian endometriomas from hemorrhagic cysts at MR imaging: utility of the T2 dark spot sign. Radiology 271(1):126–132 Scarfone G, Bergamini A, Noli S, et al. (2014) Characteristics of clear cell ovarian cancer arising from endometriosis: a two center cohort study. Gynecol Oncol 133:480–484 Tanaka YO, Yoshizako T, Nishida M, et al. (2000) Ovarian carcinoma in patients with endometriosis: MR imaging findings. AJR 175:1423–1430 Koshiyama M, Matsumura N, Konishi I (2014) Recent concepts of ovarian carcinogenesis: Type I and Type II. Biomed Res Int 2014:934261 Terada T (2012) Endometrioid adenocarcinoma of the ovary arising in atypical endometriosis. Int J Clin Exp Pathol 5(9):924–927 Kurman RJ (2014) WHO Classification of Tumours of Female Reproductive Organs, vol. 6, 4th edn. Lyon: IARC Prat J (2012) New insights into ovarian cancer pathology. Ann Oncol 23(Supplement 10):x111–x117 Author information Authors and Affiliations Corresponding author Rights and permissions About this article Cite this article Lopes Dias, J., Veloso Gomes, F., Lucas, R. et al. The shading sign: is it exclusive of endometriomas?. Abdom Imaging 40, 2566–2572 (2015). https://doi.org/10.1007/s00261-015-0465-1 Published: Issue date: DOI: https://doi.org/10.1007/s00261-015-0465-1

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Condition tags

endometriosis

MeSH descriptors

Carcinoma, Endometrioid Endometrial Neoplasms Endometriosis Magnetic Resonance Imaging Adult Aged Aged, 80 and over Carcinoma, Endometrioid Diagnosis, Differential Endometrial Neoplasms Endometriosis Endometrium Endometrium Female Humans Middle Aged Reproducibility of Results Retrospective Studies Sensitivity and Specificity Young Adult

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