Cryptococcus gattii infection is endemic in immunocompetent populations within tropical and subtropical countries including Australia and, unlike C. neoformans, C. gattii infection is more likely to result in cryptococcomas within the brain and lungs [1]. On CT imaging, these cryptococcomas may be indistinguishable from tumours, leading many patients to be erroneously investigated down a cancer pathway. This review illustrates one such case, and aims to highlight key differences in their presentation and imaging findings.

Background of the Condition Cryptococcosis is a systemic mycosis, caused predominantly by Cryptococcus gattii in immunocompetent individuals, acquired from inhalation of spores from pigeon droppings and certain eucalypts[2,3]. Clinical features are variable but predominantly involve a combination of meningitis (67%) [1], papilloedema (15%) [4], and cryptococcomas within the lung (67%) that can cause general respiratory symptoms or be asymptomatic altogether [5]. Cutaneous involvement may be rarely present with different morphologies including ulcers and subcutaneous masses, and may be the first manifestation of disseminated cryptococcosis in...

Imaging of pulmonary cryptococcal disease predominantly shows nodules that may occasionally be cavitating, with surrounding ground-glass opacity [15,16]. There may also be mediastinal lymphadenopathy and pleural effusions. FDG uptake is variable but FDG-avid nodules may mimic malignancy. Radiographic presentation of intracranial disease is variable, depending on the form of infection. CT findings may be non-specific and up to 40% of scans are reported as normal; MRI is the modality of choice. Meningeal disease typically shows leptomeningeal and pachymeningeal enhancement on T1 C+, and a high...

The cryptococcomas caused by C. gattii infection are generally indistinguishable from tumours on CT imaging. Given the marked statistical prevalence of malignancy compared to C. gattii even in countries where infection is endemic, most patients are investigated down a cancer pathway with further CT and PET-CT scans that again cannot distinguish between the two. It is typically only after biopsy that MRI brain is performed and characteristic lesions are found. This exposes the patient to substantial radiation and procedural risk. Given the primary distinguishing features...

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