Delayed pancytopenia following ingestion of wild mushrooms consistent with Hypholoma fasciculare: A case report

RATIONALE: Hypholoma fasciculare (sulfur tuft) is a toxic mushroom commonly associated with gastrointestinal symptoms. However, hematologic toxicity related to Hypholoma species has rarely been reported. In particular, delayed-onset pancytopenia following mushroom ingestion remains poorly understood. PATIENT CONCERNS: A 57-year-old man presented to the emergency department after ingesting self-collected wild mushrooms. Approximately 10 days after ingestion, he developed fever and generalized weakness. DIAGNOSES: Laboratory evaluation revealed delayed-onset pancytopenia. Extensive infectious, autoimmune, and hematological investigations, including viral serology and bone marrow examinations, excluded primary hematological malignancies, aplastic anemia, and infectious causes. Based on the clinical course and the exclusion of alternative etiologies, toxin-mediated bone marrow suppression following mushroom ingestion was considered the most plausible diagnosis. INTERVENTIONS: The patient was conservatively managed with close monitoring and supportive care. No specific antidotal or immunosuppressive agents were administered. OUTCOMES: Hematological parameters gradually recovered without targeted interventions. Follow-up laboratory tests demonstrated complete resolution of the pancytopenia, and the patient remained clinically stable without recurrence during outpatient follow-up. LESSONS: This case highlights delayed pancytopenia as a potential manifestation of toxic mushroom ingestion, even in the absence of severe initial symptoms. Recognition of this pattern may facilitate a timely diagnosis and appropriate monitoring.