Occam or Hickham? the Diagnostic Dilemma of an Inflammatory Brain Lesion in the Setting of Pulmonary Aspergillosis and Previous Neurosurgery

INTRODUCTION:Occam's Razor is a precept which invites one to consider the simplest and most unifying diagnosis as correct. In the modern era, clinical diagnosis remains critical in selecting appropriate therapies yet grows ever more complex with increased information from diagnostic technologies, but not always with sufficient granularity to answer the clinical question with certainty. We present an example of this dilemma in a patient with complex partial seizures on a background of pulmonary aspergillosis and historic clipping of a middle cerebral artery (MCA) aneurysm.CASE DESCRIPTION:A 69-year-old female presented with progressive headaches, temporal lobe seizures, poor short-term memory and weight loss. She had suffered a subarachnoid haemorrhage 22 years earlier requiring surgical repair of a right MCA aneurysm. She was treated for breast cancer in 2006 followed by pulmonary aspergilloma in 2014 for which systemic antifungals were discontinued due to toxicity. Imaging revealed a right temporal inflammatory lesion adjacent to the aneurysm clip. Gastrointestinal toxicity and haemoptysis complicated the clinical and radiological response to systemic steroids. Cerebral aspergillosis was considered given her medical history despite an equivocal fungal screen, but intolerable side effects negated the continued use of systemic antifungals. Surgical exploration to establish a definitive diagnosis and potentially treat the underlying cause was recommended despite the high surgical risk involved and subsequently revealed a foreign body type granuloma, and excluded aspergillosis. Tuberculosis and other granulomatous disease processes were excluded.CONCLUSION:This case illustrates the importance of pathological diagnosis to guide therapy and reminds us that the occasional patient will encounter multiple, rare and unrelated diseases during their lifetime. A high index of suspicion is necessary in patients who have undergone surgical aneurysm repair involving muslin as it may be subject to secondary infection and or granuloma formation many years later.