Looking for the “connection”: A clinical vignette on pediatric chest wall masses

Abstract

Chest wall masses in the pediatric population are relatively rare, and the differential diagnosis predominantly includes neoplastic soft tissue or osseous tumours, either benign or malignant in etiology, although local infectious processes represent additional diagnostic possibilities. Among recent immigrants, a more diverse array of less commonly observed pathogens warrant consideration. Here, we present a case of a chest wall mass in an immunocompetent child who had recently immigrated from the Philippines.

Case Presentation

An 11-year-old female presented to the local emergency department for evaluation of a new left-sided chest wall mass along with subjective fevers 9 weeks after immigrating to Canada from the Philippines. Three weeks prior to presentation, she had developed intermittent, low-grade, left-sided pleuritic chest and back pain. She was evaluated in the emergency department at that point with chest radiography demonstrating a focal opacity in the anterior left upper lobe. No specific therapy was initiated at that time. Subsequently, symptoms evolved to include daily fevers, chills, drenching night sweats, and a mild non-productive cough with no sputum production or hemoptysis. Additionally, she noted a slowly growing left anterior chest wall mass, which was tender to palpation.

The patient’s medical history was significant for appropriately treated active pulmonary tuberculosis diagnosed at 8 months of age, as well as multiple dental caries for which she had undergone recent extractions in the Philippines. She was not taking prescribed or over-the-counter medications and had no medication allergies. Her family history was significant for latent tuberculosis in her father, for which he had been appropriately treated.

On examination, she was febrile with a temperature of 38.6°C. Pertinent positive findings included a left anterior chest wall mass measuring 3 cm × 3 cm, which was violaceous in colour and tender to palpation but without warmth, sinus tracts, or discharge. Respiratory examination revealed bronchial breath sounds and fine inspiratory crackles in the left upper lobe. There was no lymphadenopathy, hepatomegaly, splenomegaly, or stigmata of infective endocarditis.

Initial investigations revealed a normal white blood cell count of 8.7 × 10⁹/L with normal differential, thrombocytosis (381 × 10⁹/L) and an elevated C-reactive protein level of 53 mg/L. Computed tomography of the chest demonstrated a left upper lobe loculated lesion measuring 2.9 cm × 4.8 cm × 6.1 cm, along with a solid and well-vascularized heterogeneous lesion in the rectus abdominus muscle measuring 5 cm × 1.5 cm (see Figure 1).

Figure 1:

Computed tomography of the chest demonstrating an airspace opacity in the anterior left upper lobe (A) abutting the anterior thoracic wall with associated pleural effusion and (B) overlying chest wall involvement

Based on the initial non-infectious and infectious diagnostic considerations, an excisional biopsy of the chest wall mass and a number of microbiologic investigations were ordered.

Diagnosis

Initial microbiologic investigations included one sputum culture which showed growth of usual respiratory flora, three sputum cultures which were negative for acid-fast bacilli and for mycobacterial growth, and three sets of aerobic and anaerobic blood cultures which showed no growth.

An excisional biopsy of the chest wall mass was negative for acid-fast bacilli and mycobacterial and fungal growth but did demonstrate light growth of Aggregatibacter actinomycetemcomitans. Pathology showed evidence of acute and chronic non-granulomatous inflammation.

The patient was subsequently diagnosed with empyema necessitatis in the setting of a prior dental procedure. She was started on ceftriaxone 2 g intravenously daily for 8 weeks, followed by amoxicillin 45 mg/kg orally twice daily for 4 weeks.

The patient was seen regularly in follow-up, and at the completion of therapy had returned to normal activities and was without any residual pleuritic pain, respiratory symptoms, or systemic symptoms. Complete blood count and inflammatory markers had normalized. Chest ultrasonography showed resolution of the abdominal wall mass, and chest X-ray showed resolution of the left upper lobe lesion. At this time, antimicrobials were discontinued.

Discussion

Empyema necessitatis, or “empyema of necessity,” is a rare process that results from extension of an area of empyema through the parietal pleura into adjacent soft tissue structures in the chest wall. As an infectious process, it was reportedly first described by Gullan de Baillon in 1640 following the rupture of a syphilitic aneurysm. While historically Streptococcus pneumoniae and Mycobacterium tuberculosis accounted for the vast majority of cases, in the antibiotic era inadequately treated necrotizing pneumonia or pulmonary abscess is the primary contributor, and anaerobic pathogens are most often recovered (1–3).

Aggregatibacter actinomycetemcomitans, first described as a human pathogen in 1920, is a facultative anaerobe, gram-negative, coccobacillus organism in the family Pasteurellaceae (4). Formerly known as Actinobacillus actinomycetemcomitans, it derives its species name from the observation that early isolates were often recovered concomitantly with Actinomyces species. Aggregatibacter actinomycetemcomitans is a recognized pathogen in empyema necessitatis in pediatric populations, with a recent literature review outlining three such cases due to monomicrobial Aggregatibacter actinomycetemcomitans infection. Cases occurred in patients aged 11 to 14 years. Symptom duration prior to presentation ranged from 2 months to 1 year, and all were treated for a minimum of 3 months with clinical resolution (5).

This case reinforces the diagnostic approach to chest wall masses in pediatric patients with special emphasis on empyema necessitatis, an unusual consequence of an underlying respiratory process which can easily be mistaken in pediatric populations for a malignant soft tissue or osseous process (6). While sending surgical specimens for pathologic evaluation is certainly necessary, they should also be evaluated in the microbiology lab for both typical and atypical pathogens.

Funding Statement

Publication of this article was funded by the Association of Medical Microbiology and Infectious Disease (AMMI) Canada.

Competing Interests:

The authors have nothing to disclose.

Ethics Approval:

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Informed Consent:

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Registry and the Registration No. of the Study/Trial:

N/A

Animal Studies:

N/A

Funding:

Publication of this article was funded by the Association of Medical Microbiology and Infectious Disease (AMMI) Canada.

Peer Review:

This article has been peer reviewed.