Myeloid sarcoma with megakaryoblastic differentiation mimicking a sellar tumor

Abstract

Myeloid sarcoma (MS) is a localized extra-medullary tumor mass of immature myeloid cells, arising de novo or related to acute myeloid leukemia, of which it can be a forerunner, a coinciding or late event. Less commonly, MS represents an acute blastic transformation of myelodysplastic syndromes or myeloproliferative neoplasms. This rare condition commonly consists of a proliferation of more or less immature cells with a myeloid immunophenotype, very exceptional cases showing a megakaryoblastic or erythroid differentiation. The most common localization of MS is the skin, lymph node, soft tissues and bones, but CNS involvement is exceedingly rare, with no cases reported in the sellar region. We report a 54-year-old man, affected by myeloproliferative neoplasm, JAK2 V617F-positive of 13 years duration, who acutely presented with a third cranial nerve palsy; neuroradiology documented a space-occupying lesion at the level of the sellar, upper clival and right parasellar regions, that was sub-totally removed with a trans-sphenoidal approach. The histological examination documented a proliferation of large, blastic cells, frequently multinucleated; a diagnosis of MS with megakaryoblastic differentiation, arising in a background of chronic idiopathic myelofibrosis, was suggested by immunohistochemistry, owing to CD42b, CD45, CD61 and LAT (linker for activation of T cells) positivity. In addition, homozygous JAK2 V617F mutation was detected from the myeloid sarcoma specimen. A few weeks after surgery, an acute blastic leukemic transformation occurred and, despite chemotherapy, the patient died 2 months after surgery. To the best of our knowledge, this is the first MS case with megakaryoblastic differentiation arising within the CNS.

Lombocruralgie gauche révélant un sarcome granulocytaire à différenciation mégacaryocytaire

“…Une différenciation érythroïde ou mégacaryoblastique est exceptionnelle [5]. La révélation par une atteinte rachidienne compliquée d'une radiculalgie par envahissement de l'espace épidural reste une manifestation inhabituelle [6].…”

Myeloid sarcoma of the skull base: A case report and systematic literature review

“…Data regarding demographics, presenting symptoms, imaging characteristics, leukemia diagnosis, metastases status, preoperative and postoperative symptoms, and findings were obtained from the included articles [ Table 2 ]. [ 8 , 9 , 13 , 17 - 19 ]…”

Myeloid Sarcoma with Megakaryoblastic Differentiation Arising in the Conjunctiva

“…Destructive bone foci are due to the preferential subperiosteal localization of the malignant deposits. Lesions surrounding the brain and parasellar region can produce neuro-ophthalmic symptoms and dysfunctions, but myeloid sarcomas of the brain parenchyma are vanishingly rare [8]. …”