Histiocytic sarcoma

ICD-O-2 Morphology

9723/3: True histiocytic sarcoma
Effective 1992 - 2000

ICD-O-3 Morphology

9755/3: Histiocytic sarcoma
Effective 2001 and later


for cases diagnosed 1992 and later

Primary Site(s)

See Module 7
Most common sites of involvement: lymph nodes, skin, intestinal tract, soft tissue


Not Applicable

Module Rule


Alternate Names

Histiocytic medullary reticulosis [OBS]
Malignant histiocytosis [see code 9751/3]
Monocytic sarcoma
True histiocytic lymphoma
True histiocytic sarcoma


Histiocytic sarcoma is a malignant proliferation of cells showing morphological and immunophenotypic features of mature tissue histiocytes. Neoplastic proliferations associated with acute monocytic leukemia are excluded.

Abstractor Notes

Rarely, systemic presentation with multiple sites of involvement may be seen, and is sometimes referred to as "malignant histiocytosis".

This is a very aggressive neoplasm with a usually poor response to therapy.

Definitive Diagnostic Methods

Genetic testing
Histologic confirmation

Genetics Data

Clonal Ig rearrangements
TCR rearrangements are lacking


Absence of markers from non-histiocytic cells
CD4 positive
CD15 weak expression
CD45 positive
CD45RO positive
CD68 (KP1 and PGM1) expression
CD163 expression
HLA-DR positive
Lysozyme expression


Hematologic Transplant and/or Endocrine Procedures
Hormone therapy
Radiation therapy

Transformations to

There are no known transformations

Transformations from

There are no known transformations

Corresponding ICD-9 Codes

200.0 Reticulosarcoma
202.3 Malignant histiocytosis

Corresponding ICD-10 Codes

C96.3 True histiocytic lymphoma

Corresponding ICD-10-CM Codes (U.S. only)

C96.A Histiocytic sarcoma (effective October 01, 2015)

Signs and Symptoms

Skin lesions (solitary and innumerable)
Weight loss

Diagnostic Exams

Progression and Transformation

Most patients die of progressive involvement reflecting the high clinical stage at presentation (stage III-IV) in the majority of patients

Epidemiology and Mortality

Age: 52 years median age (infancy to elderly age range)
Incidence: rare, limited number of reported cases
Sex: male predominance
Survival: generally poor, 60-80% of patients die from progressive involvement


Swerdlow SH, Campo E, Harris NL, Jaffe ES, Pileri SA, Stein H, Thiele J (Eds):
WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues (Revised 4th edition)
IARC: Lyon 2017
Section: Histiocytic and dendritic cell neoplasms
Pages: 468-470

International Classification of Diseases for Oncology, Third Edition, First Revision. Geneva: World Health Organization, 2013.
Section: ICD-O-3.1 (2011) Morphological Codes

National Cancer Institute
Section: General Information About Adult Non-Hodgkin Lymphoma (NHL)