Teaching Case

Our 60-year-old patient was diagnosed with stage IIIB nodular sclerosing Hodgkin’s lymphoma and after completion of cycle 3 of ABVD (adriamycin, bleomycin, vinblastine & dacarbazine), he presented with a one-week history of exertional dyspnoea, fever and non-productive cough with oxygen saturation circa 90% in room air.

PET with FDG showed increased avidity in the mid-zone to base of the lung during acute phase of bleomycin-induced pneumonitis (clinical event). CT Thorax similarly showed ground glass opacification of the mid to lower zone of the lung. Follow-up scan for re-staging and coincidentally matching 3 months after steroidal treatment for bleomycin-induced pneumonitis showing complete resolution of the disease.

Clinical Perspective: Suspecting an infectious aetiology, he was initially started on broad spectrum antibiotics (piptazobactam) and trimethoprim-sulfamethoxazole added when the clinical condition failed to improve. Poor response to antimicrobials led to a suspicion of bleomycin-induced pneumonitis (BIP) which was further supported by PET with FDG findings [1]. High dose steroid treatment (100mg Prednisolone) was commenced with significant resolution of respiratory symptoms within 48hours. Antibiotics were stopped and a tapering dose of steroids over 3 months continued.

Imaging Perspective: PET images attached show initial staging, clinical event (BIP) and post-treatment resolution images. At presentation with the clinical event (BIP), there was increased FDG avidity affecting the middle and lower lobes of the lung in comparison to the initial staging scan. CT Thorax similarly showed ground glass opacification of the mid to lower zone of the lung. This imaging feature coupled with a pulmonary function test showing a restrictive ventilatory pattern led to a clinical diagnosis of bleomycin-induced pneumonitis. Interestingly, this gentleman’s re-staging PET scan provided useful information both on treatment response (Hodgkin’s lymphoma) and resolution of pneumonitis [2].

Teaching Points: BIP is a major pulmonary toxicity issue and significantly reduces 5-year overall survival in patients treated with the ABVD regimen for Hodgkin’s lymphoma [3]. The gold standard in making a diagnosis remains tissue biopsy and histological analysis. However, these patients are almost always acutely unwell, thus a challenge to any invasive diagnostics. Characteristic CT findings of BIP include ground glass opacification of the posterobasal region with bilateral peripheral infiltrates [4]. However, other differentials with similar CT findings and clinical presentation such as opportunistic infection, radiation toxicity and cardiogenic interstitial oedema need to be systematically ruled out. PET scanning with FDG has shown promise in detecting BIP and differentiating active inflammation from chronic scarring [5]. Combining clinical presentation, PET imaging findings and respiratory function test as with our case could potentially allow early recognition and treatment of bleomycin-induced pneumonitis.