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Age / Sex : 87 / F
Chief complaint : Incidental found right buttock mass
What is your diagnosis?
Two weeks later, you can see the final diagonosis with a brief discussion of this case (Please submit only one answer)
Courtesy : 한 석 (Seok, Hahn), 인제대학교 해운대 백병원 (Inje University Haeundae Paik Hospital)
Diagnosis: Foreign body granuloma
Discussion
Findings
CT
1. A 6cm, well defined ovoid tumor in the right gluteus maximus, with peripheral enhancement
2. With internal high dense portion on non-contrast CT, without contrast enhancement
MRI
1. T2 low SI and T1 low SI of central portion, (high density on pre CT)
2. T2 intermediate to high SI, and T1 intermediate SI with enhancement of peripheral portion
Discussion
- Foreign body granuloma -
Tissue reaction for retained foreign bodies after skin-penetrating trauma
Iatrogenic gossypiboma by retained surgical sponge during operation
Formed by reactive macrophage proliferation -> grow slowly without giving rise to significant symptoms -> difficult to differentiate from tumor
History of antecedent skin penetrating trauma or previous operation
Foreign body granuloma into consideration as a differential diagnosis from soft tissue tumors
- MRI features of foreign body granuloma -
Useful for chronic and complicated foreign bodies
Foreign body appears as hypo-intensity or signal void on both T1- and T2WI
Appearance of surrounding soft tissue varies
Recently entered : hypo SI on T1WI and hyper SI on T2WI
Long standing : granulation tissue undergone structural alterations
Well encapsulated multiloculated cystic mass -> seroma, liquefied hematoma, cold abscess or cystic degeneration within soft tissue sarcoma
Infection, draining sinuses with markedly enhancing walls on post contrast T1WI
Central linear hypo SI or signal void with in a mass ->thin long foreign body and look as a target sign
References
1. Adonis Manzella et al. Imaging of Gossypobomas: Pictorial reciew. AJR 2009;193:S94-S101
2. Johan L. Bloem et al. Bone and soft tissue tumors of hip and pelvis. European journal of radiology 2012;(81):3793-3801
3. Brunioi C. Carneiro et al. Multimodality imaging of foreign bodies: New insight s into old challenges. RadioGraphics 2020;40:1965-1986
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