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Name
Solitary plasmacytoma of bone (SPB)
Reportable
for cases diagnosed
1978 and later
Primary Site(s)
C400-C419
Primary site must be bone (C400-C419). The most common bones involved are the vertebrae. The thoracic vertebrae are more commonly involved then the cervical or lumbar. Other common bones include the ribs, skull, pelvis, femur, clavicle, and scapula.
If unable to determine primary site, assign primary site C419
See Plasma Cell Myeloma, 9732/3 if there are multiple plasmacytomas or the bone marrow is involved.
See abstractor notes.
If unable to determine primary site, assign primary site C419
See Plasma Cell Myeloma, 9732/3 if there are multiple plasmacytomas or the bone marrow is involved.
See abstractor notes.
Coding Manual:
Hematopoietic Coding Manual (PDF)
Abstractor Notes
The presence of multiple plasmacytomas is diagnostic of plasma cell myeloma. Code as C421 (bone marrow), 9732/3.
Note: Code primary site as C421 even if the bone marrow is negative or the bone marrow was not assessed.
Solitary plasmacytoma of bone (SPB) is part of the Plasma cell neoplasms and other diseases with paraproteins lineage table in the WHO 5th edition of Hematolymphoid Tumors. (See Appendix B in the Hematopoietic Manual, Table B17)
The phrase "plasma cell neoplasm" is an umbrella term used for many diseases, some of which are not reportable. If the only diagnosis is "plasma cell neoplasm," then do not report this case. If it is "plasma cell neoplasm" consistent with a plasmacytoma or multiple myeloma, then the case would be reportable.
If the diagnosis is "plasmacytoma" and there is no additional information to indicate if it's a plasmacytoma of the bone or an extramedullary plasmacytoma, default to plasmacytoma of the bone and assign histology, 9731/3 and primary site C419.
The presence of a plasmacytoma and a diagnosis of plasma cell myeloma diagnosed during the initial clinical workup is evidence of advanced disease. One primary is abstracted, the plasma cell myeloma (See Rule M11)
The presence of a plasmacytoma after a diagnosis of plasma cell myeloma is evidence of advanced disease and not a new primary (See Rule M13)
SPB mainly arises in bones with active haematopoiesis, affecting the axial skeleton more often than the appendicular skeleton. The spine is most commonly involved, followed by pelvis, ribs, skull, and long bones.
This is a localized solitary tumor in the bone consisting of monoclonal plasma cells. Complete skeletal radiographs (preferably MRI) show no other lesions. If additional lesions are found on MRI or CT (or other radiological surveys), this is diagnostic of plasma cell myeloma (see 9732/3).
There is no evidence of bone marrow plasmacytosis other than the solitary lesion. Vertebral lesions may be associated with symptomatic cord compression.
Patient presents with bone pain at the site of the lesion or with a pathological fracture. Soft tissue extension may produce a palpable mass.
An M-protein is found in the serum or urine in 24-72% of patients.
Note: Code primary site as C421 even if the bone marrow is negative or the bone marrow was not assessed.
Solitary plasmacytoma of bone (SPB) is part of the Plasma cell neoplasms and other diseases with paraproteins lineage table in the WHO 5th edition of Hematolymphoid Tumors. (See Appendix B in the Hematopoietic Manual, Table B17)
The phrase "plasma cell neoplasm" is an umbrella term used for many diseases, some of which are not reportable. If the only diagnosis is "plasma cell neoplasm," then do not report this case. If it is "plasma cell neoplasm" consistent with a plasmacytoma or multiple myeloma, then the case would be reportable.
If the diagnosis is "plasmacytoma" and there is no additional information to indicate if it's a plasmacytoma of the bone or an extramedullary plasmacytoma, default to plasmacytoma of the bone and assign histology, 9731/3 and primary site C419.
The presence of a plasmacytoma and a diagnosis of plasma cell myeloma diagnosed during the initial clinical workup is evidence of advanced disease. One primary is abstracted, the plasma cell myeloma (See Rule M11)
The presence of a plasmacytoma after a diagnosis of plasma cell myeloma is evidence of advanced disease and not a new primary (See Rule M13)
SPB mainly arises in bones with active haematopoiesis, affecting the axial skeleton more often than the appendicular skeleton. The spine is most commonly involved, followed by pelvis, ribs, skull, and long bones.
This is a localized solitary tumor in the bone consisting of monoclonal plasma cells. Complete skeletal radiographs (preferably MRI) show no other lesions. If additional lesions are found on MRI or CT (or other radiological surveys), this is diagnostic of plasma cell myeloma (see 9732/3).
There is no evidence of bone marrow plasmacytosis other than the solitary lesion. Vertebral lesions may be associated with symptomatic cord compression.
Patient presents with bone pain at the site of the lesion or with a pathological fracture. Soft tissue extension may produce a palpable mass.
An M-protein is found in the serum or urine in 24-72% of patients.
Diagnostic Confirmation
This histology can be determined by positive histology (including peripheral blood) with or without genetics and/or immunophenotyping. Review the Definitive Diagnostic Methods, Immunophenotyping and Genetics Data sections below, and the instructions in the Hematopoietic Manual for further guidance on assigning Diagnostic confirmation.
Module Rule
Module 2: PH3, PH4
Alternate Names
Definition
Plasmacytoma is a solitary neoplasm of clonal plasma cells without evidence of plasma cell (multiple) myeloma or end-organ damage due to plasma cell neoplasia. (WHO 5th edition)
Definitive Diagnostic Methods
Cytogenetics
Genetic testing
Histologic confirmation
Immunohistochemistry
Immunophenotyping
Genetics Data
Ig clonal rearrangements, complex karyotypes with multiple chromosomal gains/losses; also translocations, deletions, mutations
Immunophenotyping
IgG+ (expression/positive)
EBV- (no expression/negative)
Treatments
Radiation therapy
Surgery
Transformations to
Transformations from
None
Same Primaries
Corresponding ICD-10 Codes (Cause of Death codes only)
C90.2 Plasmacytoma, extramedullary
Corresponding ICD-10-CM Codes (U.S. only)
C90.3 Solitary plasmacytoma (effective October 01, 2015)
Signs and Symptoms
M-protein found in serum or urine
Palpable mass due to soft tissue expansion
Diagnostic Exams
Blood and urine immunoglobulin studies
Blood chemistry studies
Bone marrow aspiration and biopsy
Cytogenetic analysis
Serum and urine protein electrophoresis and immunofixation
Tissue biopsy
Twenty-four-hour urine test
Progression and Transformation
2/3 of patients eventually evolve to generalized myeloma or additional solitary or multiple plasmacytomas
Epidemiology and Mortality
Age: 55 years median age
Incidence: 3-5% of plasma cell neoplasms
Sex: male predominance
Survival: 1/3 of patients remain disease free at 10 years, median overall survival 10 years
Sources
WHO Classification of Tumours Editorial Board. Haematolymphoid tumours. Lyon (France): International Agency for Research on Cancer; 2024. (WHO classification of tumours series, 5th ed.; vol. 11). https://publications.iarc.who.int/637.
Section: Plasma cell neoplasms and other diseases with paraproteins
Pages: Part B: 622-624
Section: Plasma cell neoplasms and other diseases with paraproteins
Pages: Part B: 622-624
International Classification of Diseases for Oncology, 3rd edition (including revisions). Geneva: World Health Organization, 2001, 2011, 2020.
Section: ICD-O-3.2 (2020) Morphological Codes
Pages: http://www.iacr.com.fr/index.php?option=com_content&view=category&layout=blog&id=100&Itemid=577
Section: ICD-O-3.2 (2020) Morphological Codes
Pages: http://www.iacr.com.fr/index.php?option=com_content&view=category&layout=blog&id=100&Itemid=577
PDQ® Adult Treatment Editorial Board. PDQ Plasma Cell Neoplasms (Including Multiple Myeloma) Treatment. Bethesda, MD: National Cancer Institute. Updated <03/28/2025>. Available at: https://www.cancer.gov/types/myeloma/hp/myeloma-treatment-pdq. Accessed <03/30/2025>. [PMID: 26389362]
Section: Plasma Cell Neoplasms (Including Multiple Myeloma) Treatment (PDQ®)–Health Professional Version
Pages: https://www.cancer.gov/types/myeloma/hp/myeloma-treatment-pdq
Section: Plasma Cell Neoplasms (Including Multiple Myeloma) Treatment (PDQ®)–Health Professional Version
Pages: https://www.cancer.gov/types/myeloma/hp/myeloma-treatment-pdq
