Myeloid sarcoma: an uncommon presentation of myeloid neoplasms; a case series of 4 rare cases reported in a tertiary care institute.

Puneet Baveja Toyaja Jadhav

doi:10.4322/acr.2021.339

Abstract

ABSTRACTMyeloid sarcoma (MS) is a rare extramedullary neoplasm of myeloid cells, which can arise before, concurrently with, or following hematolymphoid malignancies. We report 04 such cases of MS, diagnosed in this institute over a period of 6 years, during various phases of their respective myeloid neoplasms/leukemias. These cases include MS occurring as a relapse of AML (Case 1), MS occurring as an initial presentation of CML (Case 2), MS occurring during ongoing chemotherapy in APML (Case 3), and MS presenting as a progression of MDS to AML (Case 4). In the absence of relevant clinical history and unemployment of appropriate immunohistochemical (IHC) studies, these cases have a high risk of being frequently misdiagnosed either as Non-Hodgkin’s Lymphoma (NHL) or small round cell tumors or undifferentiated carcinomas, which may further delay their management, making an already bad prognosis worse. This case series has been designed to throw light on the varied presentation of MS and the lineage differentiation of its neoplastic cells through the application of relevant IHC markers along with their clinical correlation.

Highlights

CASE REPORTSMyeloid sarcoma (MS), known as Granulocytic Sarcoma or Chloroma, is a rare extramedullary manifestation of hematological malignancies of myeloid origin
It is characterized by the formation of clinically evident tumors containing immature myeloid cells in extramedullary sites, commonly involving the skin, soft tissues, central nervous system (CNS), and the urogenital tract
We report a series of 04 cases of MS reported in this institute over 06 years, diagnosed histopathologically during different clinical phases of their respective myelogenous neoplasms/leukemias

Summary

INTRODUCTION

Myeloid sarcoma (MS), known as Granulocytic Sarcoma or Chloroma, is a rare extramedullary manifestation of hematological malignancies of myeloid origin. The atypical cells within the lymph node, established as blasts, showed reactivity for CD34 along with MPO, CD43, CD56, and CD117 with a Mib-1 labeling index of 70-80% (Figure 4C-F) These features confirmed the diagnosis of Myeloid sarcoma in a freshly detected case of CML with blast crises. Microscopic evaluation of the cervical mass revealed focal endocervical lining and few endocervical glands with stroma showing infiltration by atypical monomorphic cells arranged in sheets, cords, and singly scattered, at places encroaching upon the endocervical glands (Figure 8A) These atypical cells were large to medium in size and exhibited a high N:C ratio, scant cytoplasm, round to oval nucleus, open chromatin and few prominent nucleoli. The atypical cells showed reactivity for MPO, LCA, and CD117 (Figure 8B-D) These microscopic characteristics, along with immunohistochemical profile, confirmed the diagnosis of myeloid sarcoma in a case of secondary AML, indicating the leukemic transformation of MDS - EB2.

Findings

DISCUSSION

CONCLUSION