Geotrichum candidum: A rare primary pathogen in pulmonary geotrichosis

A 50 yr old male†, a known diabetic who was on irregular treatment, was admitted to the Chest Medicine department, Burdwan Medical College, Bardhaman, India, in February 2019, with complaints of intermittent fever and haemoptysis for the last one month. Chest X-ray showed a fibrocavitary lesion in the right upper zone, and high-resolution computed tomography scan of the thorax revealed a soft-tissue mass with cavitation and surrounding consolidation at the right upper lobe (Fig. 1). Haematoxylin and eosin-stained fine-needle aspiration cytology smear showed inflammatory cells, degenerated cells, foci of necrosis, ill-formed epithelioid cell granulomas and sheets of mesothelial cells. There were small branched hyaline hyphae and barrel-shaped arthroconidia (Fig. 2). Sputum and aspirated fluid from lung lesion both were negative for Ziehl-Neelsen stain, CBNAAT (cartridge-based nucleic acid amplification test), MGIT (mycobacteria growth indicator tube) and bacteriological culture. 10% KOH mount showed hyaline hyphae. On Sabouraud's dextrose agar media, colonies showed a creamy yeast-like consistency. Lactophenol cotton blue preparation showed rectangular arthroconidia with rounded ends. Some arthroconidia had hyphal extensions giving typical 'hockey stick' appearance. These findings established the evidence of 'fungal ball' by Geotrichum candidum. Previous studies have suggested that pre-existing pulmonary diseases such as tuberculosis and pneumonia by Klebsiella pneumoniae are more significant than neoplasms as a predisposing factor for pulmonary geotrichosis. This case is unique as G. candidum is the sole causative agent in the immunocompromised diabetic patient. The patient improved after antifungal therapy for three months.

Fig. 1.

High-resolution computed tomography scan of the thorax showing soft-tissue mass with cavitation with surrounding consolidation on the right upper lobe (arrow).

Fig. 2.

Fine-needle aspiration cytology smear (H and E stain, ×1000) showed inflammatory cells (arrow), degenerated cells (arrow), foci of necrosis (arrow), ill-formed epithelioid cell granulomas (arrow) and sheets of mesothelial cells (arrow). There were barrel-shaped arthroconidia (typical hockey-stick appearance) suggestive of Geotrichum candidum (arrow).