1. Presented by Tait Huso, M.D. and reviewed by Sean Zhang, M.D., Ph.D.

A patient underwent laminectomy of spinal vertebrae requiring revision with additional hardware placement and CSF leak repair. The patient's recovery is complicated by recurrent pain and radiculopathy. Follow up MRI findings are consistent with localized discitis/osteomyelitis of the vertebrae with a locular effusion that is concerning for an abscess.

Biopsy tissue specimens are collected and sent to the microbiology lab. Initial bacterial cultures remain negative for growth.

The specimen submitted for fungal cultures is negative on calcofluor white stain. After one week of incubation there is light growth of grey colonies with aerial mycelium that have a cobweb-like/moth-eaten wool appearance and microscopically show singular or small cluster of “pumpkin seed”-like conidia on top of a conidiophore (annellide) with swelling structure towards the base (Figure 1).

What is the most likely organism in this case?