A woman presented with a 5-month left inguinal painless nodule. The patient had a history of pancreatic cancer and a 2-year bilateral inguinal/groin incisions for saphenectomy.
Long axis gray-scale US (Fig.1) shows a hypoechoic area (red arrows) in the left inguinal subcutaneous soft tissue, with irregular margins and no posterior acoustic enhancement. In addition, a central internal echogenic focus (yellow arrow) is also revealed. Power Doppler US (Fig. 2) reveals a hypervascular nodule. The short axis gray-scale (Fig. 3) and power Doppler US (Fig. 4) reveal the same findings, but other paracentral internal echogenic foci are also visible (yellow arrows).
Suture granulomas may occur after a surgical intervention. They are most commonly reported in the setting of inguinal herniorrhaphy, but can occur in other post-surgical settings as well [1]. Eldridge et al. [2] reported that the time lag between the operation and the formation of a suture granuloma was helpful for differential diagnosis. They reported that almost all suture granulomas developed within two years after the operations, but others [3] reported that the time interval varied from several months to years.
The pathogenesis of suture granulomas involves two steps. The first step is the initial reaction of the tissue, which reflects the amount of injury inflicted by the passage of the needle. After the initial reaction subsides, the suture material causes specific inflammatory reactions (second step) [4]. Histologically they are characterised by multinucleated phagocytic cells containing phagocytosed suture material [5].
These tumour-like lesions usually develop slowly and may cause only vague symptoms or remain asymptomatic for many years [6]. Prior surgical history is helpful for radiologic diagnosis.
Ultrasonography is an accurate way to identify and characterise them by depicting suture material within. In general, the granuloma appears as an ill-defined hypoechoic mass [6] (representing inflammation) with central or paracentral internal echogenic foci (as in this case) corresponding to the suture material [7]. These criteria can be helpful in the inguinal area for differentiating suture granulomas from chronic haematomas or metastatic soft tissue deposits but can also be helpful in another areas such as the cervical area, where these typical characteristics allow its differentiation from locally recurrent tumours in the thyroid bed [7], or even in the hypogastic region where suture granulomas can mimic an urachal tumor on CT but can be differentiated by these ultrasound appearances [1]. Suture granulomas present as enhancing masses on MRI or CT, and can be associated with increased uptake at F-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET)/CT imaging [8], thus, if there is suspicion that a mass may be a suture granuloma on MRI or CT, a follow-up ultrasound may identify linear hyperechoic suture material within the lesion, and help suggest the diagnosis of a suture granuloma.
Suture granuloma
Ultrasound imaging reveals a poorly delineated hypoechoic mass in the patient’s left inguinal region, with a central or para-central hyperechoic spot consistent with postoperative suture or foreign material. Doppler examination indicates a small amount of blood flow within the lesion. Combining the patient’s previous inguinal surgery history and the images provided, the lesion’s location largely corresponds to the surgical incision site.
Based on the patient’s previous surgical history, the slow growth pattern of the lesion, and the presence of hyperechoic suture artifact within the mass on ultrasound, the most likely diagnosis is postoperative suture granuloma. If necessary, ultrasound-guided aspiration or intraoperative pathological examination can be performed to confirm the diagnosis.
Treatment Strategy:
Rehabilitation and Exercise Prescription:
Disclaimer: This report is a reference-based analysis derived from the available information and does not replace in-person consultation or professional medical advice. For specific diagnosis and treatment, please consult your specialist or visit a qualified healthcare facility. Any treatment or exercise program should be adapted to the individual’s condition and carried out under the guidance of a specialist or rehabilitation therapist.
Suture granuloma
