Radiographic findings of myeloid sarcomas (chloroma)

Abstract

Clinical Presentation

A 47-year-old woman in remission for acute myeloid leukemia (AML) after chemotherapy and hematopoietic stem cell transplant presented with recurrent headaches and vision loss over the last 6 months. Computed tomography revealed multiple diffuse high-density regions suggestive of neuro-parenchymal hematomas. Magnetic resonance imaging demonstrated multiple diffuse hypointense (T1) and hyperintense (T2) regions involving the middle cranial fossae, cribriform plates, the posterior ethmoidal air cells and upper olfactory recesses, and the left cavernous sinus and sellar region including the anterior clinoid process and greater wing of the sphenoid. A diffuse leptomeningeal enhancement and bilateral oculomotor and trigeminal nerve involvement was also evident along with mild communicating hydrocephalus, flattening of the optic disc and mild paranasal mucositis.

Differential Diagnosis

include chloromas (recurrent leukemia with extramedullary involvement), hematomas and primary or metastatic neoplasms such as neuroblastomas and lymphomas.

Diagnosis and Management

Magnetic resonance imaging is particularly useful in the diagnosis and follow-up imaging of cerebrospinal chloromas as computed tomography findings may be indeterminate. Diagnostic confirmation was via histology and immunohistochemistry, demonstrating specific molecular markers. The patient received 5 cycles of chemotherapy with high dose methotrexate, hydrocortisone and cytarabine.

Conclusion

Myeloid sarcomas, also known as chloromas, are extramedullary tumor-like proliferations of primitive myeloid cells. These myeloperoxidase rich, greenish masses represent a rare and unique presentation of AML (2.5-9%). Considered a distinct entity from classic leukemic infiltrates, these may occur either concurrently/ as a precursor to AML or even more rarely in AML remission cases, especially those treated with hematopoietic stem cell transplant like the case presented here. Their development in AML remission may represent a suboptimal response to chemotherapy or a graft-vs.-leukemia response. The propensity for involvement of the maxillofacial structures is noteworthy and important for oral radiologists to recognize. A multidisciplinary approach involving radiologists, hematologists/ oncologists and pathologists is required for accurate diagnosis and appropriate management.