Dental extractions: a necrotizing infection mimicking a metastasis

The challenge of differential diagnosis between cutaneous metastasis and necrotizing infection

In patients with non-small cell lung cancer (NSCLC), the appearance of a cutaneous mass clinically suggests metastasis, a complication affecting 1 to 12% of cases and associated with a poor prognosis with an average survival of 5 to 6 months. However, necrotizing skin and soft tissue infections (NSTI) can mimic these malignant lesions, creating a complex diagnostic dilemma. This case report documents the management of a 61-year-old man presenting with an 8 x 8 cm necrotic thoracic abscess, whose initial CT imaging suggested direct parietal extension of his spiculated lung mass.

The objective of this presentation is to demonstrate how an odontogenic pathology can lead to severe systemic complications simulating neoplastic progression. The study analyses the direct link between a decayed dentition, a recent complete dental extraction, and the haematogenous dissemination of oral germs. The clinical hypothesis explores the capacity of commensal micro-organisms, such as Streptococcus constellatus and Actinomyces odontolyticus, to generate a severe NSTI in an oncological patient. This case highlights the need for high suspicion regarding oral germs to establish source control and targeted antibiotic therapy, thus avoiding treatment delay related to a metastatic misinterpretation.

Design and protocol of the case study

This clinical case report documents the management of a single 61-year-old patient, recently diagnosed with non-small cell lung cancer (NSCLC). The investigation aimed to establish the etiology of a suspicious skin lesion mimicking a lung metastasis.

The diagnostic and therapeutic protocol followed these steps:

• Surgical procedure: Incision and initial drainage of an 8 x 8 cm cavity located on the chest wall, presenting a necrotic abscess evolving for two weeks.
• Medical imaging: Use of computed tomography (CT) to assess the extension of the spiculated pulmonary mass and its potential involvement in the chest wall.
• Microbiological analyses: Performing cultures from samples of the abscessed cavity and blood cultures to identify any potential systemic dissemination.
• Targeted anamnesis: Investigation of recent history, revealing a dentition in poor condition and a complete dental extraction performed shortly before the onset of symptoms.

The analysis focused on identifying bacterial strains through culture, highlighting the presence of Streptococcus constellatus and Actinomyces odontolyticus. Follow-up was maintained until clinical improvement under targeted antibiotic therapy and the patient's discharge.

Clinical and microbiological results

This clinical case study concerns a 61-year-old patient, recently diagnosed with non-small cell lung cancer (NSCLC), presenting with a necrotic chest wall abscess evolving for two weeks. Surgical exploration revealed an 8 x 8 cm cavity requiring incision and drainage.

Qualitative imaging observations (CT) initially directed the diagnosis toward cutaneous metastasis, showing a spiculated lung mass extending directly into the chest wall. However, the worsening of the clinical condition after drainage led to thorough microbiological investigations.

The analysis of the anamnesis revealed poor oral health status and a recent complete dental extraction. These elements, correlated with the microbiological results, confirm a necrotizing soft tissue infection (NSTI) of odontogenic origin with hematogenous dissemination, rather than direct metastatic progression. The patient showed significant clinical improvement following the administration of targeted antibiotic therapy.

Differential diagnosis: when infection mimics metastasis

This clinical case illustrates a major diagnostic challenge: a necrotic thoracic lesion in a patient with non-small cell lung cancer (NSCLC). While the literature reports cutaneous metastases in 1 to 12% of lung cancer cases (associated with an average survival of 5-6 months), the results of this study show that infection can mask malignancy. Here, the 8 x 8 cm necrotic abscess was not a tumour extension, but a necrotising soft tissue infection (NSSTI) of odontogenic origin, confirmed by the presence of Streptococcus constellatus and Actinomyces odontolyticus.

Limits and perspective

As this is a single case report, the generalisation of these observations remains limited. However, the strength of this study lies in the precise identification of the causal link between the oral health status and the systemic complication. The patient presented a decayed dentition and had undergone a recent complete dental extraction. This study highlights that the practitioner must not be confined to an obvious oncological diagnosis when faced with skin necrosis, at the risk of delaying vital targeted antibiotic therapy.

Implications for clinical practice

For the dental surgeon and the implantologist, this case serves as a reminder that invasive procedures (total extractions) in polymorbid patients can lead to the hematogenous dissemination of oral pathogens. Management of the primary infectious focus is crucial to avoid distant complications mimicking severe pathologies. Vigilance must be increased during the post-operative follow-up of oncological patients, where an opportunistic infection can rapidly decompensate and simulate tumor progression.

Summary of study results

This case report details a necrotizing soft tissue infection (NSTI) in a 61-year-old male, initially suspected to be a cutaneous metastasis of lung carcinoma. Microbiological identification of Streptococcus constellatus and Actinomyces odontolyticus in an 8x8 cm abscessed cavity and blood cultures allowed the infection to be linked to a recent full dental extraction in a context of polycaries.

In concrete terms, for the practitioner:

• Expanded odontogenic suspicion: In the presence of unexplained skin abscesses or necrotic lesions, even at a distance and in an oncological context, systematically look for an oral infectious focus or a history of recent extraction.
• Bacteremic risk management: Commensal oral flora (notably the Anginosus group) can cause severe hematogenous dissemination; rigorous pre- and post-operative asepsis control is crucial in fragile patients.
• Differential diagnosis: Do not assume a cutaneous metastasis without excluding an opportunistic infection, as targeted antibiotic management and control of the infectious source determine the vital prognosis.

Technical lexicon of the study

Cutaneous metastasis: Secondary localization of a cancerous process in the integument. In the context of lung cancer, they occur in 1 to 12% of patients and are associated with a poor prognosis with an average survival of 5 to 6 months.

NSSTI (Necrotizing Skin and Soft Tissue Infection): Necrotizing infection of the skin and soft tissues. These pathologies represent a major diagnostic challenge and require rapid management (including source control and antibiotic therapy) to prevent rapid systemic decompensation.

Streptococcus constellatus: Bacterium belonging to the Streptococcus anginosus group. In this clinical case, this germ was isolated in both the thoracic abscess cultures and the blood cultures, highlighting its capacity for haematogenous dissemination.

Actinomyces odontolyticus: Commensal anaerobic micro-organism of the oropharyngeal flora. Its presence in an extra-oral necrotic lesion is often linked to poor dentition or recent dental interventions, such as the complete extraction reported in this patient.

Spiculated pulmonary mass: Radiological description (CT scan) of a tumor lesion whose edges present irregular extensions. Here, the mass extended from the lung toward the chest wall, initially mimicking direct neoplastic invasion or metastasis.

Source control: Therapeutic strategy consisting of physically eliminating the source of infection (incision, drainage, debridement, or dental extraction). This is an essential step to stabilize the patient before or alongside the administration of targeted antibiotics.

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