Extramedullary relapse presenting as trigeminal neuralgia and diplopia after allogeneic hematopoietic stem cell transplantation.

A 23-year-old woman presented with trigeminal neuralgia four months after hematopoietic stem cell transplantation (HSCT) for acute myeloblastic leukemia. No leukemic cells were found in the cerebrospinal fluid. Initial brain magnetic resonance imaging (MRI) did not reveal any abnormality. After symptom exacerbation with diplopia, second MRI showed an irregular mass at the right petrous apex, with uniform enhancement and a clear margin which was interpreted as a meningioma. The pathology and immunohistochemistry finally confirmed the diagnosis of granulocytic sarcoma. This case suggests that granulocytic sarcoma should be remembered as a very rare and a malignant pathology in the differential diagnosis of neurologic complications following HSCT.