A Silent Threat Unveiled: Invasive Fungal Sinusitis in a High-Risk Hematologic Malignancy Patient.

Invasive fungal sinusitis (IFS) poses a fatal threat to patients with hematological malignancies or a history of allogeneic hematopoietic stem cell transplant (HSCT). While invasive aspergillosis, a subtype of IFS, remains rare in immunocompetent individuals, allogeneic HSCT recipients face a notable surge in incidence. Despite the rapid onset and progression of IFS, its clinical presentation is subtle, contributing to heightened mortality rates. Prompt surgical debridement and systemic antifungal therapy are required to yield positive results. Examining IFS cases in HSCT recipients is vital, providing insights into its clinical course, prevention strategies, and improved evaluation. We present a rare presentation of IFS with Aspergillus niger in a relapsed acute myeloid leukemia patient post-HSCT. Two weeks after chemotherapy, the patient developed headaches and blood-tinged sinus drainage in the setting of pancytopenia. Radiologic and pathological findings confirmed the diagnosis of IFS, necessitating weeks of intensive anti-fungal therapy. Despite the initial positive response, the disease ultimately progressed to a fatal outcome. This case emphasizes that early detection is required for a favorable treatment response. Furthermore, it underscores the importance of heightened clinical suspicion, risk stratification, multidisciplinary care, and ongoing research for optimal management of IFS in allogeneic HSCT recipients.