Suture granulomas are localised inflammatory reactions in response to retained suture material. A similar process may also occur in certain situations with mesh repairs 5. Ultrasound is often used as first-line imaging modality. It may be confused with a tumour or a recurrent tumour after surgery and should be considered in the differential in the correct setting.
Usually develops slowly after an intervention. It may become a palpable and tender mass, mimicking tumour or recurrent tumour.
A suture granuloma represents a benign granulomatous proliferation in response to a retained foreign body. They less commonly occure with absorbable sutures, but may still occur.
Obtaining a history of prior surgery with a surgical approach around the area of concern is important. Suture granulomas can present in the neck after thyroidectomy, mimicking recurrence 4.
High-frequency (>10 MHz) linear probe is useful.
- hypoechoic collection
- a small hyperechoic structure in the collection (the suture) is highly specific
- often has parallel hyperechoic 'rail-like' morphology
- may show mild vascularity on colour Doppler
- may be FDG avid, mimicking neoplasm 2-3
Treatment and prognosis
The treatment of choice is resection of the retained suture and surrounding inflammatory tissue.
General imaging differential considerations include
- 1. Rettenbacher T, Macheiner P, Hollerweger A et-al. Suture granulomas: sonography enables a correct preoperative diagnosis. Ultrasound Med Biol. 2001;27 (3): 343-50. Pubmed citation
- 2. Takeshita N, Tohma T, Miyauchi H et-al. Suture Granuloma With False-Positive Findings on FDG-PET/CT Resected via Laparoscopic Surgery. Int Surg. 2015;100 (4): 604-7. doi:10.9738/INTSURG-D-14-00140.1 - Pubmed citation
- 3. Kikuchi M, Nakamoto Y, Shinohara S et-al. Suture granuloma showing false-positive finding on PET/CT after head and neck cancer surgery. Auris Nasus Larynx. 2012;39 (1): 94-7. doi:10.1016/j.anl.2011.04.012 - Pubmed citation
- 4. Chung YE, Kim EK, Kim MJ et-al. Suture granuloma mimicking recurrent thyroid carcinoma on ultrasonography. Yonsei Med. J. 2006;47 (5): 748-51. Free text at pubmed - Pubmed citation
- 5. Falagas ME, Kasiakou SK. Mesh-related infections after hernia repair surgery. Clin. Microbiol. Infect. 2005;11 (1): 3-8. doi:10.1111/j.1469-0691.2004.01014.x - Pubmed citation