A 52-year-old woman complained of pain, swelling and functional impairment on the second digit of the hand 6 weeks after she punctured the finger with a cactus thorn.
A 52-year-old right-handed woman complained of pain, swelling and functional impairment on the proximal phalanx of the second digit of the right hand for several days. Six weeks before she punctured the ungloved finger with a cactus thorn in a domestic accident. She was treated with antibiotics and non-steroidal anti-inflammatory drugs, without complete regression of the symptoms. Plain radiograph and ultrasound (US) of the right hand were performed.
Penetrating injuries and suspected retained foreign bodies are a common reason for emergency department visits. Detection is important because they may lead to serious infectious and inflammatory complications. Only 15% or less of wooden foreign bodies are detected with radiography. Those invisible on conventional radiographs can often be easily identified on sonograms. All soft-tissue foreign bodies are initially hyperechoic on sonography. If they are present in the soft-tissues longer than about 24 hours, the ensuing inflammatory reaction can create a hypoechoic rim around the echogenic foreign body. This rim of granulation tissue, edema, or hemorrhage, increases the conspicuity of foreign bodies on US. Sonographic artifacts also aid in identification. The artifact occurring deep to a foreign body depends primarily on its surface attributes rather than its composition. Smooth and flat surfaces produce dirty shadowing or reverberation artifact, whereas irregular surfaces and those with a small radius of curvature produce clean shadowing. Sonography plays an important role for the detection of non-opaque foreign bodies, and has been shown to accurately demonstrate their size, shape, and location. For radiopaque foreign bodies, US can provide more precise localization and improved assessment of the surrounding soft-tissues, depicting fluid collections, tendon disorders, and injury to neurovascular structures. In our case, sonographic description of the location and characteristics of the foreign body was valuable by minimizing surgical exploration, and a cactus thorn was surgically removed without complications.
Soft tissue foreign body (cactus thorn).
Based on the patient’s hand X-ray films (frontal and oblique views), there is no clear disruption of bony continuity, and no obvious fracture line or noticeable bone destruction. Plant-based foreign bodies (such as wooden or spiny structures) often appear with low density or may be invisible on conventional X-ray. Thus, there is no clear anomalous density or foreign body visible in this series of plain films. Additionally, there is no significant soft tissue thickening or calcification.
Ultrasound examination, however, shows a linear hyperechoic structure within the soft tissue of the second finger, surrounded by a mild hypoechoic rim, indicating the presence of a retained foreign body and an accompanying inflammatory or granulomatous reaction. This linear hyperechoic structure has a relatively smooth surface, potentially accompanied by slight posterior shadowing or “dirty shadowing,” which differs from the typical ultrasound features of metal or glass foreign bodies.
Considering the patient’s history (cactus spine injury followed by local pain, swelling, and activity limitations persisting for 6 weeks), and the imaging findings (ultrasound showing a linear hyperechoic foreign body with surrounding hypoechoic inflammatory changes), the following diagnoses can be considered:
Based on the history of trauma (cactus spine prick), persistent local discomfort for 6 weeks, and the ultrasound findings of a characteristic linear hyperechoic foreign body with surrounding hypoechoic inflammatory changes, the most likely diagnosis is:
“Retained cactus spine in the soft tissue of the finger with local inflammatory granuloma formation.”
This diagnosis aligns with the clinical and imaging findings. Ongoing inflammatory response and irritation can result in pain, swelling, and functional impairment.
Treatment Strategy:
Rehabilitation and Exercise Prescription:
Throughout the rehabilitation process, closely monitor changes in local pain, swelling, and functional recovery. If significant pain or new swelling occurs, seek medical evaluation promptly.
Disclaimer: The above analysis is based on the provided patient information and imaging data, intended as a reference for clinical decision-making. It does not replace an in-person consultation or professional medical advice. Specific treatment plans should be formulated by a specialized clinician in accordance with the patient’s actual condition.
Soft tissue foreign body (cactus thorn).
