• FDG-PET
• acute myeloid leukemia
• chloroma
• extramedullary
• granulocytic sarcoma
• myeloid sarcoma

• Humans
• Female
• Sarcoma, Myeloid/diagnosis
• Leukemia, Myeloid, Acute
• Breast Neoplasms/diagnosis
• Mammography
• Magnetic Resonance Imaging

Extramedullary myeloid sarcoma (MS) of the breast is a rare disease, representing 0.12% of all diagnoses of acute myeloid leukemia. We review a case of a 27-year-old female who presented with a palpable right breast mass. She subsequently underwent a biopsy, which showed breast tissue with diffuse infiltrate of blasts compatible with MS. A bone marrow biopsy was performed with no evidence of leukemia or lymphoma. Therefore, a second breast biopsy was obtained for additional testing and cytogenetics which demonstrated positive (t8;21)(q22;q22) translocation associated with acute myeloid leukemia. Patient was admitted for induction of chemotherapy, but she subsequently developed neutropenic colitis and C. diff colitis. Unfortunately, her condition quickly deteriorated, and she passed away shortly after. This report aims to describe the clinical, radiographic, and pathological features of a case of extramedullary MS involving the breast.

Myeloid sarcoma (MS) is relatively rare, occurring mainly in the skin and lymph nodes, and MS invasion of the ulnar nerve is particularly unusual. The main aim of this article is to present a case of MS invading the brachial plexus, causing ulnar nerve entrapment syndrome, and to further clinical understanding of the possibility of MS invasion of peripheral nerves.

We present the case of a 46-year-old man with a 13-year history of well-treated acute nonlymphocytic leukaemia who was admitted to the hospital after presenting with numbness and pain in his left little finger. The initial diagnosis was considered a simple case of nerve entrapment disease, with magnetic resonance imaging showing slightly abnormal left brachial plexus nerve alignment with local thickening, entrapment, and high signal on compression lipid images. Due to the severity of the ulnar nerve compression, we surgically investigated and cleared the entrapment and nerve tissue hyperplasia; however, subsequent pathological biopsy results revealed evidence of MS. The patient had significant relief from his neurological symptoms, with no postoperative complications, and was referred to the haemato-oncology department for further consultation about the primary disease. This is the first report of safe treatment of ulnar nerve entrapment from MS. It is intended to inform hand surgeons that nerve entrapment may be associated with extramedullary MS, as a rare presenting feature of the disease.

MS invasion of the brachial plexus and surrounding tissues of the upper arm, resulting in ulnar nerve entrapment and degeneration with significant neurological pain and numbness in the little finger, is uncommon. Surgical treatment significantly relieved the patient’s nerve entrapment symptoms and prevented further neurological impairment. This case is reported to highlight the rare presenting features of MS.

• Myeloid sarcoma
• Ulnar nerve entrapment syndrome
• Acute nonlymphocytic leukaemia
• Sarcoma
• Upper limb surgery
• Case report

• Breast
• bone marrow transplantation
• breast sarcoma
• myeloid sarcoma

Patient: Female, 24

Final Diagnosis: Myeloid sarcoma of the breast

Symptoms: Breast lump

Medication: —

Clinical Procedure: Core needle biopsy

Specialty: Radiology