Under pressure: progressively enlarging facial mass following high-pressure paint injection injury

Abstract

High-pressure paint injection injuries are relatively rare industrial accidents and almost exclusively occur on the non-dominant hand. A rarely documented complication of these injuries is the formation of a foreign body granuloma. We report a case of a 33-year-old man presenting with extensive facial scarring and progressive right paranasal swelling 7 years after a high-pressure paint injury. After imaging investigations, an excision of the mass and revision of scarring was performed. Access to the mass was gained indirectly through existing scarring over the nose to ensure an aesthetic result. Histological analysis revealed a florid granulomatous foreign body reaction to retained paint. To the best of our knowledge, this is the first reported case of a facial high-pressure paint injury with consequent formation of a foreign body granuloma.

Background

Industrial accidents involving high-pressure paint sprayers are rare but potentially catastrophic. Owing to vocational factors, these injuries predominately occur to the non-dominant hand. Under high pressure, paint can penetrate the skin and disperse through subcutaneous tissues leading to fibrosis and ischaemia. A rarely documented long-term complication of these injuries is a foreign body granuloma, which may present a diagnostic challenge. We report the investigation and surgical management of the first reported foreign body granuloma caused by a facial high-pressure paint injection injury. In addition, we briefly review the pathophysiology, management and prognosis of high pressure injection injuries and foreign body granulomas.

Case presentation

A 33-year-old Caucasian man presented to the Ear, Nose and Throat clinic, with a progressively enlarging right paranasal swelling extending from the right side of the nose to the medial canthus, which was starting to cause discomfort and obstruct vision from the right eye (figure 1). He described an industrial accident to the area—7 years prior, while trying to unblock a high-pressure paint sprayer—which was managed conservatively. The paint was believed to be emulsion paint, however, the operating pressure of the sprayer was unknown. The accident left him with hypertrophic and abnormal scarring over the right ala and the dorsum of the nose. On examination, the swelling was firm, and flexible nasoendoscopy showed no abnormal nasal architecture. The patient was otherwise healthy and further history was unremarkable.

Figure 1.

Anterior view of face. Arrow (→) points to mass and asterisk (*) highlights hypertrophied scars. Inferior view of face. Arrow (→) points to mass and asterisk (*) highlights hypertrophied scars. Note that the mass obstructs the patient's inferonasal field of view.

Investigations

Initial CT imaging indicated a minimally calcified venous malformation on the right cheek arising from the angular and facial veins (figure 2), and an ultrasound scan was recommended for further assessment. The ultrasound scan (US) demonstrated a lobular lesion measuring 3.7×2.3×1.2 cm, confined to the subcutaneous layer (figure 3). Some internal vascularity was demonstrated on Doppler scanning, however, the aetiology of the mass was uncertain, therefore a definitive diagnosis using biopsy was advised.

Figure 2.

CT scan illustrating a lesion in proximity to the right angular vein. The lesion is circled and the arrow (→) points to the right angular vein.

Figure 3.

Ultrasound scan of the right cheek illustrating a subcutaneous mass extending from the right medial canthus.

Differential diagnosis

The differential diagnoses for a firm facial subcutaneous mass are:

• Sebaceous cyst

• Post-traumatic osteoma or osteochondroma

• Venous malformation

• Foreign body granuloma

Owing to the history of a conservatively managed high-pressure paint injury, there was a high index of suspicion for a foreign body granuloma. CT scanning raised the possibility of a venous malformation, however, the likelihood of this was reduced after US scanning. In addition, although exceedingly rare, extraskeletal osteomas and osteochondromas were a possible differential as they may form at sites of soft tissue injury¹ and progressively enlarge over time.² The CT scan indicated a minimally calcified lesion and subsequent US scan demonstrated a lobular mass, which reduced the likelihood of a bony tumour.

Treatment

The aims of treatment were to gain a definitive diagnosis, reduce the size of the lesion to improve function, and to improve cosmesis. An indirect surgical approach was used, with access to the mass gained through existing facial scars (figure 4). Intraoperative finding was a dense fibrotic mass accounting for previous CT findings (figure 5). The mass was excised and samples were sent for histological analysis. The scars were revised for an aesthetic result (figure 6).

Figure 4.

Intraoperative photograph of surgical access gained through existing transverse nasal scar and exploration of subcutaneous tissue in the right maxillary area.

Figure 5.

Intraoperative photograph of excision of granulomatous mass.

Figure 6.

Immediate postoperative photograph showing final result with revision of scarring.

Outcome and follow-up

The histology report confirmed a florid foreign body reaction to black pigment particles and fragments of positively bifringent material (figure 7). As the mass was not malignant, a postoperative CT was not carried out. After a 2-week follow-up the patient had noticed an improvement in pain and vision. He was satisfied with the cosmetic result from the revision of scarring. The case has been followed up for 12 months with no significant recurrence.

Figure 7.

Histological slide of a tissue sample showing black pigment particles, clear bifringent particles and giant cells, indicative of a foreign body granuloma.

Discussion

High-pressure paint injuries are part of a wider class of uncommon occupational injuries called high-pressure injection injuries. The most commonly injected materials are paint, hydraulic fluid, water and grease—normally occurring on the index finger of the non-dominant hand.³ The initial injury is often small, however, the injected material can track widely through subcutaneous tissue, leading to a dual mechanism of damage. Direct trauma causes high-pressure necrosis, which may be further compounded by an inflammatory response caused by chemical toxicity.⁴ The symptoms and prognosis are dependent on the toxicity, pressure and volume of the material as well as the expansile capacity of the tissue compartment.³ In general, an aggressive treatment approach is advocated including an expert surgical opinion in all cases.^5–7 In injuries to the hand, the long-term prognosis is poor with few returning to work due to loss of function caused by fibrosis.⁸

In contrast to injuries to the hand, there are few reports of high-pressure injection injuries to the face,^{9 10} and only one ophthalmological case involved paint.¹¹ In one case of an acutely presenting high-pressure grease gun injury, the pressures involved were high enough to allow penetration through the maxillary sinus and into the infratemporal fossa.⁹ The injuries sustained in our case were not as severe, which may be due to the lower operating pressure of the paint sprayer or due to the tangential direction of the injury. This can be deduced from the more medial distribution of scarring compared to the subcutaneous granuloma.

There are few reports of foreign body granulomas forming after high-pressure paint injection injuries. The granulomas may present a diagnostic challenge as in one case the granuloma was initially misdiagnosed as a giant cell tumour of the tendon sheath even after biopsy and histological analysis.¹² The three main constituents of paint are vehicle, solvent and pigment. The vehicle and solvent evaporate to leave behind the pigment, which is identified as dark particles in our tissue sample (figure 7). Granulomatous reactions to a wide variety of pigments have been extensively reported in the context of tattoos, both medical and non-medical, and are believed to be immune reactions to metallic ions present in the pigment.^{13 14} In addition to pigment particles, there are clear bifringent particles in the granuloma (figure 7) that may be talc particles, added to give the paint a matte appearance.¹² Talc is well known to cause the formation of foreign body granulomas when inhaled^{15 16} or injected intravenously,¹⁷ and may enhance the inflammatory response in this case. In general, the formation of foreign body granulomas consists of a chronic immune response to foreign particles too large to be phagocytosed. The sequence of events includes protein adsorption, macrophage adhesion, macrophage fusion and the formation of giant cells,¹⁸ which are visible in our tissue sample (figure 7).

Mason and Queen¹⁹ describe the experience of Hesse in treating 183 ‘artificial granulomas’ caused by Russian conscripts self-injecting various oils in order to avoid military service during the revolutionary era. In particular, the difficulties in surgical management due to the intimate association with neurovascular structures and difficulties in achieving haemostasis were noted. Recently, non-operative techniques for foreign body granulomas caused by cosmetic fillers have been described, including injectable bleomycin, anti-mitotics and steroids, in addition to systemic therapies and pulsed lasers.^20–22 However, there is currently no clear consensus on the optimal therapy. In one series of 173 cases, surgical management was shown to be superior to injectable therapies for the management of facial foreign body granulomas caused by fillers. The authors concluded that surgical management was optimal for large facial granulomas that were having a significant impact on cosmesis, or for cases refractory to injectable treatment.²³ The aforementioned treatment modalities are advocated for management of foreign body granulomas caused by dermal fillers, however, it is not clear whether the same modalities should be used in foreign body granulomas caused by high-pressure injection injuries, as these may be located deeper and involve a greater volume of material. The long-term prognosis of untreated granulomas is poor, as fistulae, fibrosis and scarring eventually occur.^{19 22} Unfortunately, there is a relatively high rate of recurrence in foreign body granulomas treated both operatively and non-operatively.²³

To conclude, high-pressure paint injuries require specialist acute management. The mechanism of damage is both traumatic and inflammatory, leading to long-term sequelae. Retained material can cause foreign body granulomas that may present many years after the initial injury. The treatment of granulomas is complex and there is currently no consensus on the optimal strategy. There are limited reports of facial high-pressure paint injuries and this is the first to report a long-term complication.

Learning points.

• Acute high-pressure paint injuries require treatment as a surgical emergency.

• The prognosis is variable and depends on the pressure, site of injury, type and amount of material.

• Injected material can disperse widely from the point of entry, which may pose challenges to surgical management.

• Retained paint may cause a granulomatous foreign body reaction that can present many years after the initial injury.

• Granulomas may be managed using non-operative or operative treatment, however, there is little consensus on the optimal treatment strategy.