Utility of PET scan in diagnosis and monitoring descending necrotizing mediastinitis complicating Lemierre’s syndrome

Excerpt

A 76-year-old woman was admitted at our department because of a 3-day history of fever up to 39 °C, sore throat, and neck pain, associated with a left erythematosus supraclavicular swelling (Fig. 1; panel a). She reported no other significant comorbidities except the surgical excision of a breast lobular carcinoma 7 years prior with a subsequent negative follow-up. At admission, the patient appeared seriously ill, and rapidly developed dysphagia, dyspnoea, and confusion. Laboratory findings showed an elevated C-reactive protein and neutrophil leucocytosis, whereas repeated blood culture resulted negative. Neck ultrasonography revealed a segmental thrombosis of the left internal jugular vein with inflammatory tissue in the adjacent soft tissues, leading to the diagnosis of Lemierre’s syndrome (LS). Exudate in the supraclavicular and lateral cervical tissues with extension to the upper mediastinum above the tracheal carina was confirmed by neck and chest computed tomography (CT) scan (Fig. 1; panel b). Piperacillin–tazobactam and anticoagulation were started, with initial partial clinical benefit. Nevertheless, 2 days after treatment initiation, the patient experienced a clinical deterioration with sepsis and dyspnoea, but the extension of the infection appeared unmodified on the repeated CT scan. Given her previous oncologic medical history, we performed on the same day a total body positron emission tomography (PET) scan that revealed a massive metabolic active lesion, beginning from the left oro-hypopharynx and involving the supraclavicular and lateral cervical regions, with extension below the tracheal carina to both the anterior and lower posterior mediastinum (Fig. 1; panel c). These findings were compatible with an extended form of descending necrotizing mediastinitis (DNM). Antibiotic therapy was modified with imipenem and metronidazole with progressive clinical benefit, fever remission, and normalization of laboratory findings. An ultrasound-guided tru-cut biopsy performed after the resolution of the septic state showed a inflammatory xanthogranulomatosis with no evidence of any underlying neoplastic lesion. The patient was discharged after 30 days of intravenous antibiotic treatment in good clinical condition, and was followed with PET scans. The 3-month PET scan outlined a complete resolution of the infection and no evidence of residual increased metabolic tissue activity (Fig. 1; panel d).

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