A rare case of acute promyelocytic leukemia with focal bone marrow involvement presenting as a paraspinal myeloid sarcoma

Abstract

Acute promyelocytic leukemia (APL) accounts for 5-8% of acute myeloid leukemias (AMLs). Myeloid sarcomas (MS) are rare extramedullary tumors consisting of immature myeloid cells. These tumors may develop de novo or concurrently with AML and may precede or coincide with the occurrence of AML. The occurrence of MS in an APL patient is a rare clinical event. In these cases, it usually occurs as a sign of relapse. Focal bone marrow involvement by APL is also rare; the majority of cases of APL demonstrate a diffusely hypercellular bone marrow throughout the axial skeleton due to expansion of neoplastic blasts/promyelocytes. We describe a 23-year-old female who presented with gait problems, including multiple falling episodes, and lower extremity weakness. An MRI demonstrated a paraspinal soft tissue mass. Histopathologic analysis demonstrated a myeloid sarcoma expressing CD45, myeloperoxidase, CD117, BCL2, focal weak CD34, and weak CD99 and negative for CD30, TdT, CD20, CD3, and CD10. The bone marrow aspirate demonstrated blasts/promyelocytes accounting for approximately 26% of the total bone marrow aspirate cellularity. The bone m a r r o w b i o p s y a n d c l o t s e c t i o n d e m o n s t r a t e d normocellularity with a few blast/promyelocyte foci on the clot section accounting for approximately 5% of total bone marrow cellularity. These foci expressed MPO and CD117 and were negative for CD34. Flow cytometry demonstrated blasts accounting for approximately 31% of all CD45+ events expressing MPO,

A Case of Acute Promyelocytic Leukemia Presenting as Sternal Infiltrate

“…Out of these 17 patients, 13 patients had presence of concurrent marrow disease along with extramedullary presentation. [1,2,3,6,10,11,12,13,14,15,16,19,20] Out of these 13, in 3 patients bone marrow morphology was negative for abnormal promyelocytes but the presence of disease was being demonstrated by either cytogenetics or molecular methods similar to present case [2,10,6]. While in remaining 10 patients disease was demonstrable on bone marrow morphology as well as on cytogenetics and molecular methods.…”

“…The mean age was 26.7 years (median being 23 years), out of which 6 were children . Table 1 summarizes the clinical and laboratory features of all these cases [1][2][3][4]6,[9][10][11][12][13][14][15][16][17][18][19][20] .The various sites reported were sternal mass in 1 [4] as also seen in the present case, spinal/paraspinal mass in 5 [1,3,17,19,13] , bony lesion of extremities in 2 [2,9] , breast mass in 1 [10] , vertebral or skeletal lesions in 2 [6,12] , mediastinum in 2 [16,18] , cerebellum in 1 [15] , lingual mass in 1 [14], mandibular mass in 1 [11] and 1 patient presented as painful 3rd molar [20]. Out of these 17 patients, 13 patients had presence of concurrent marrow disease along with extramedullary presentation.…”

“…Myeloid sarcoma (MS) previously called as granulocytic sarcoma or chloroma is an extramedullary tumor of immature myeloid cells. [1]. MS develops in 2-8% of patients with AML and is also observed in patients with other MPN and MDS disorders [2] These tumors may precede or coincide with the occurrence of AML or present as a manifestation of disease relapse [1].…”

“…[1]. MS develops in 2-8% of patients with AML and is also observed in patients with other MPN and MDS disorders [2] These tumors may precede or coincide with the occurrence of AML or present as a manifestation of disease relapse [1]. MS may involve any organ system, from the more common sites like skin, bone, soft tissue of the head and neck, frequently the orbits and lymph nodes, to rare cases involving the heart or small intestine.…”

“…MS is extremely uncommon in APL and in many of these cases, it usually occurs as a sign of relapse [1]. In such patients with relapsed APL, extramedullary leukemic infiltrates have been most often seen in the skin (leukemia cutis) and the central nervous system (CNS) [1]. Thus myeloid sarcoma as a presenting feature of APL is a rare entity with only a few case reports mentioning this.…”