North by Northeast - a case of CNS Aspergilloma mistaken for pituitary tumour

Abstract

Background Fungal pituitary sellar infection is a rare condition and can resemble a pituitary tumour. Our patient required two debridements across two continents. Case A 47-year-old diabetic man presented with history of headaches and sudden visual loss, on neuroimaging found to have an infiltrative sella lesion compressing the optic nerves. He had an incomplete transsphenoidal resection in Nigeria, with a histological diagnosis of chordoma. Ten months prior he suffered a gunshot wound destroying his femur, initially managed with an intramedullary nail, subsequently requiring implant removal, multiple debridements antibiotic spacer, ultimately leading to a Girdlestone’s. Endoscopic redo-transphenoidal-resection at Newcastle-Upon-Tyne, for cystic/solid inflammatory changes in the pituitary fossa/sphenoid-sinus/suprasellar-cisterns suggestive of residual tumour, however did not show any neoplasm. Instead, histology yielded a chronic necrotising fungal infection, morphologically suggestive of Aspergillus on Grocott/PAS-stains, with septate branching hyphae and fruiting bodies. Culture and 18s PCR of sphenoid tissue was negative. Good therapeutic response to longterm voriconazole therapy with TDM confirming adequate levels >2 mg/L, and hormone substitution for pan-hypopituitarism. He underwent further 2-stage-arthroplasty of the hip due to polymicrobial bacterial osteomyelitis but negative fungal cultures/histology. Discussion Aspergillus infection of the pituitary fossa is rare and a recognised mimic of macroadenoma/tumour. The original lesion is likely to have been aspergillus, with diabetes as a well-established risk factor for primary paranasal fungal infection, rather than iatrogenic inoculation during surgery. Radiological/microbiological features from Girdlestones’ pointed against haematogenous spread from the osteomyelitic hip.