Table of Contents
Definition / general | Case reports | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Cytology description | Cytology images | Positive stains | Electron microscopy description | Differential diagnosisCite this page: DePond W. Myeloid sarcoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/lymphnodesAML.html. Accessed July 5th, 2020.
Definition / general
- Also called granulocytic / myeloid sarcoma or chloroma when it forms a mass
- Diagnosis requires a high degree of suspicion; thin sections are needed to see cytoplasmic granules
- Lymphadenopathy may be initial presentation, preceding marrow involvement by months or years
- May present with nodal infarction (Am J Surg Pathol 1989;13:177)
Case reports
- 43 year old woman with chronic myelofibrosis progressing to AML M7 (Eur J Haematol 2001;67:194)
Gross description
- May have green hue ("chloroma") due to myeloperoxidase, which fades on exposure to air
Gross images
Contributed by Mark R. Wick, M.D.
Granulocytic sarcoma
Images hosted on other servers:
Retroperitoneal lymphadenopathy
Subcutaneous tumor
Microscopic (histologic) description
- Cortical or sinusoidal expansion by atypical cells with preservation of follicular centers
- Blasts are large to medium size with distinct cytoplasmic borders and fine cytoplasmic granules
- Nuclei have round, folded or lobated nuclei, fine and dispersed chromatin and small to prominent nucleoli
- Often infiltrate in a single file pattern due to tumor cells insinuating between collagen fibers
- Often associated with eosinophilic myelocytes
- Auer rods may be present (Giemsa stain)
- Variable mitotic figures
- May have associated prominent sclerosis
Microscopic (histologic) images
AFIP images
Granulocytic sarcoma
Acute myeloid leukemia
Involving liver
With interspersed eosinophilic myelocytes
Cytology description
- Cytoplasmic granules in many cells
Cytology images
AFIP images
Cytologic spectrum
Positive stains
(On blasts, not other inflammatory cells)
- Myeloperoxidase, lysozyme, chloroacetate esterase (depends on AML subtype), CD43, CD99, CD117
Electron microscopy description
- Large electron dense primary cytoplasmic granules and less dense secondary granules
- May have ellipsoidal crystalloid granules
Differential diagnosis
