bubble_chart Overview

The subcutaneous node of the chest wall is the most common chest wall disease, and the lesion may invade various tissues of the chest wall. It is commonly seen in young people under 30 years old, with males being more affected. Most patients have no obvious symptoms or may experience grade I pain. The abscess may rupture spontaneously, forming a chronic non-healing sinus. The lesions are mostly found on the anterior chest wall, less frequently on the lateral chest wall, and even less commonly near the spine.

bubble_chart Etiology

The majority of chest wall subcutaneous nodes are secondary infections. The most common primary lesions are pulmonary subcutaneous nodes, pleural subcutaneous nodes, or mediastinal lymph subcutaneous nodes. However, the severity of chest wall lesions does not necessarily correlate with the extent of pulmonary or pleural lesions. Clinically, it is often observed that when a chest wall abscess appears, the primary lesion may already be inactive or healed.

There are three pathways through which the primary lesion from the lung or pleura can invade the chest wall tissues:

1. Subcutaneous node bacteria from the primary lesion in the lung or pleura invade the chest wall tissues via the lymphatic system, which is the most common route of infection. In the early stages, the subcutaneous node lesion is confined to the chest wall lymph nodes and nearby soft tissues. As the lesion progresses, the ribs, sternum, and costal cartilage may also become affected.

2. When pulmonary or mediastinal subcutaneous node lesions rupture through the pleura, they directly invade various tissues of the chest wall, including soft tissues as well as bones and cartilage, which may also be damaged. Such lesions are often interconnected with the primary pulmonary or pleural subcutaneous node foci.

3. Subcutaneous node bacteria invade the chest wall tissues via the bloodstream, where the pathogens destroy the ribs or sternum, leading to subcutaneous node osteomyelitis. As the lesion advances, it may rupture through the bone and periosteum, invading the chest wall soft tissues. Regardless of the route of invasion, in the advanced stage, the chest wall tissues will be destroyed as the lesion expands.

bubble_chart Clinical Manifestations

Early symptoms initially present as a subcutaneous nodule on the chest wall, forming a non-red, non-heated abscess without obvious signs, possibly accompanied by mild pain but lacking acute inflammatory manifestations. Fluctuation may be felt upon palpation, and aspiration may yield milky pus or a small amount of caseous material. Smears or routine cultures show no evidence of pyogenic bacteria. As the condition progresses, the mass gradually enlarges, softens, and eventually perforates the skin, forming a chronic sinus that fails to heal, leading to prolonged pus discharge.

bubble_chart Diagnosis

Among chest wall diseases, the most common is the chest wall subcutaneous node. Therefore, for a chest wall mass without acute inflammation or with a chronic sinus formation, the diagnosis of a chest wall subcutaneous node should be considered. If the patient also has subcutaneous node disease in the lungs or other organs, the likelihood of diagnosing a chest wall subcutaneous node becomes even greater. The most reliable diagnostic methods are identifying subcutaneous node bacilli from aspirated pus or performing a pathological biopsy of granulation tissue at the sinus site to confirm the diagnosis.

X-ray examination is very helpful in diagnosing chest wall subcutaneous nodes, as it may reveal subcutaneous node lesions in the lungs or pleura, destruction of ribs or sternum, or soft tissue shadows in the chest wall. However, lesions in the costal cartilage often cannot be visualized on X-ray films.

bubble_chart Treatment Measures

Subcutaneous node disease is a systemic chronic infection, and the subcutaneous node on the chest wall is merely a localized manifestation. Therefore, treatment must focus on enhancing the patient's overall resistance and administering anti-tuberculosis medications. Surgery should not be performed on patients with active pulmonary subcutaneous nodes or extensive hilar lymph node involvement. Only after the subcutaneous node disease in the lungs or other parts of the body is effectively controlled and stabilized can surgical treatment be considered for the chest wall subcutaneous node. The procedure involves complete excision of the abscess, sinus, and damaged ribs, followed by placement of a drainage strip. Two grams of streptomycin are left in the wound, and after thorough hemostasis, the incision is sutured and pressure bandaged. With the aid of antibiotics, initial-stage healing is generally achievable. Postoperatively, anti-tuberculosis medications should be continued for more than three months.

For smaller cold abscesses on the chest wall, aspiration and intracavitary injection of anti-tuberculosis drugs may be attempted. After evacuating as much pus as possible, 0.5 grams of streptomycin is injected, followed by pressure bandaging. This is repeated every three days, combined with systemic drug therapy, and some patients may achieve complete recovery.

For simple subcutaneous node abscesses on the chest wall, incision and drainage should not be performed. In cases with secondary infection, incision and drainage should be done first, along with antibiotics to control the infection. Only after the secondary inflammation is fully controlled should lesion excision be performed. If a chronic sinus has already formed, thorough surgical excision of the chest wall sinus and subcutaneous node lesion should be carried out after local and systemic anti-infection and anti-tuberculosis therapy.

bubble_chart Differentiation

1. Suppurative chest wall abscess: Local manifestations of acute inflammation are present, often accompanied by systemic infection symptoms. The course is relatively short, and pyogenic bacteria can usually be detected in the pus.

2. Spinal subcutaneous node and paravertebral abscess: Diagnosis can be confirmed by spinal X-ray examination.

3. Perforating subcutaneous nodular empyema: After puncture, the mass shows obvious shrinkage but may rapidly bulge again shortly afterward. Chest X-ray examination can confirm the diagnosis.

4. Breast subcutaneous node: Typically located in the superficial part of the pectoralis major muscle in females, at the breast area of the anterior chest wall. Clinically rare.

5. Chest wall tumors: Common chest wall tumors include soft bone tumors, soft osteosarcomas, fibrous fleshy tumors, neurofibromas, and cavernous hemangiomas. However, some soft tissue tumors may resemble cold abscesses of the chest wall, so differentiation is necessary during diagnosis.

6. Costal chondropathy: More common in young females, often affecting the 2nd to 4th costal cartilages unilaterally or bilaterally. The affected cartilage shows significant bulging with mild tenderness. Local injection of 50mg cortisone can be administered; if conservative treatment fails, surgical resection may be considered. {|105|}