Evacuation of axillary hematoma causing brachial plexus compression in newly diagnosed leukemia: a case report and literature review

Spontaneous soft tissue hematomas are recognized complications of myeloproliferative neoplasms but rarely implicate the brachial plexus. A large axillary hematoma could represent a surgical emergency due to compression of local neurovascular structures. We report a case of a 63-year-old male with a history of polycythemia vera who presented with an expansive axillary hematoma compressing his brachial plexus. The lesion's profound size caused upper limb paralysis and exquisite pain on passive movment, raised suspicion for malignant hematologic progression, and provided a localized etiology for the patient's plexopathy. Large-vessel compromise, central nervous system lesions, and soft tissue invasion were excluded by clinical evaluations and diagnostic imaging before the interdisciplinary decision was made to surgically evacuate the proven complex hematoma. The patient's pain improved following decompression and another washout two days later. Concurrent hematologic workup identified acute myelomonocytic leukemia by bone marrow biopsy and initiated appropriate management. Twenty-four abstracts were screened from PubMed using keyword search terms and citation matching. Thirteen patients were identified, 4 of which had compartment syndrome symptoms secondary to hematoma in the setting of an undiagnosed hematological malignancy. All cases in the literature were concurrently diagnosed with chronic myeloid leukemia whereas the case we present was a manifestation of acute myeloid leukemia. Extensive mass effect from a deep tissue hematoma as the chief complaint for a patient with leukemic transformation of polycythemia vera is a rare presentation. An interdisciplinary approach with meticulous hematologic workup allowed for management of both, the lesion's neuropathic mass effect and its underlying hematologic malignancy.