Bone marrow neoplastic
Bone marrow - plasma cell and lymphoid neoplasms
Plasma cell neoplasms
Plasmacytoma
Author: Genevieve M. Crane, M.D., Ph.D.
Last author update: 1 October 2017
Last staff update: 2 December 2024 (update in progress)
Copyright: 2002-2024, PathologyOutlines.com, Inc.
PubMed Search: Plasmacytoma [title]
Table of Contents
Definition / general | Essential features | Terminology | ICD coding | Epidemiology | Sites | Clinical features | Diagnosis | Laboratory | Radiology description | Prognostic factors | Case reports | Treatment | Microscopic (histologic) description | Microscopic (histologic) images | Virtual slides | Cytology description | Cytology images | Positive stains | Negative stains | Flow cytometry description | Molecular / cytogenetics description | Differential diagnosis | Additional references | Board review style question #1 | Board review style answer #1 | Board review style question #2 | Board review style answer #2Cite this page: Crane GM. Plasmacytoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/lymphomaplasmacytoma.html. Accessed December 28th, 2024.
Definition / general
- Solitary lesion of clonal plasma cells that are cytologically, immunophenotypically and genetically similar to plasma cell myeloma
- Solitary plasmacytoma of bone: localized bone tumor consisting of monoclonal plasma cells with no other radiographic lesions and no evidence of other bone marrow involvement
- Extraosseous (extramedullary) plasmacytoma: localized tumor of plasma cells (not in bone)
Essential features
- Monoclonal plasma cells, no associated clonal B cell population, isolated lesion without evidence of additional bone marrow plasmacytosis
Terminology
- Solitary plasmacytoma of bone
- Extraosseous (extramedullary) plasmacytoma
ICD coding
Epidemiology
- Bone and extramedullary tumors each comprise 3 - 5% of plasma cell neoplasms
- Both are more common in men (65%), median age 55 years
Sites
- Extraosseous: 80% in upper respiratory tract (15% spread to cervical lymph nodes)
- Other: GI, lymph nodes (Am J Clin Pathol 2001;115:119), bladder, CNS, breast, thyroid, testis, parotid, skin
- Bone:
- Areas of active hematopoiesis
- In order of decreasing frequency: vertebrae, ribs, skull, pelvis, femur, clavicle, scapula, rare in distal long bones
Clinical features
Bone:
Extraosseous (clinical features depend on site):
- Most present with bone pain
- Vertebral lesions may cause cord compression
- Palpable mass due to soft tissue extension
- Up to 2/3 progress to myeloma or additional plasmacytomas; 1/3 remain disease free for > 10 years following local (radiation) control
- 5% may have multiple or recurrent plasmacytomas but no evidence of myeloma
Extraosseous (clinical features depend on site):
- Rhinorrhea, epistaxis, nasal obstruction
- Approximately 15% progress to myeloma, 70% are disease free at 10 years
- 25% have local recurrence, may spread to regional lymph nodes or metastasize to distant sites
Diagnosis
- Monoclonal plasma cells, less frequently plasmablastic or anaplastic morphology
- Histologic findings are combined with laboratory and radiographic findings (below) showing absence of additional disease
Laboratory
- M protein in serum or urine (absent or lower than in myeloma):
- Bone: approximately 50%, usually IgG
- Extraosseous: 20%, often small, IgA
- No CRAB (hypercalcemia, renal failure, anemia, additional bone lesions)
- Unlike myeloma, normal levels of uninvolved immunoglobulins
- Monitor free light chain to measure progression
Radiology description
- MRI may be preferred method to exclude additional bone lesions
- Solitary bone lesions are usually purely lytic with a narrow zone of transition to normal bone
- Abnormalities may persist after successful treatment
Prognostic factors
Bone - poor prognostic features (in some series):
- Older patients
- Plasmacytoma > 5 cm
- Persistence of M protein following radiotherapy
- Low polyclonal immunoglobulins (also raises concern for myeloma)
- Osteopenia
Case reports
- 52 year old man with plasmacytoma involving a lymph node that evolved to plasma cell myeloma (N Engl J Med 1950;243:335)
- 67 year old African American man with extramedullary plasmacytoma associated with amyloidoma (Arch Pathol Lab Med 2002;126:969)
Treatment
- Local radiation therapy
Microscopic (histologic) description
- Similar to myeloma, may contain mature, immature, plasmablastic or anaplastic plasma cells
- Amyloid deposits may appear in extraosseous tumors as pink amorphous material with scattered multinucleated giant cells
Microscopic (histologic) images
Contributed by Genevieve M. Crane, M.D., Ph.D. and Kelly Magliocca, D.D.S., M.P.H.
Plasmacytoma
Plasmacytoma of bone with osteolytic destruction
CD138 positive and MUM1 positive
CD79 variable and CD20 negative
Core biopsy section
Core biopsy, kappa and lambda
Solitary plasmacytoma of bone
Virtual slides
Contributed by Genevieve M. Crane, M.D., Ph.D.
EBV+ tumor
Cytology description
- Similar to myeloma
- Mature plasma cells: oval with abundant basophilic cytoplasm, perinuclear hof, round eccentric nuclei, "clock face" chromatin and indiscernible nucleoli
- Immature plasma cells: higher nuclear / cytoplasmic ratio, more abundant cytoplasm and hof region compared to plasmablastic, more dispersed chromatin, often prominent nucleoli
- Plasmablastic: less abundant cytoplasm with little or no hof region, fine reticular chromatin, large nucleus ( > 10 microns) or large nucleolus ( > 2 microns) (Blood 1998;91:2501)
- Pleomorphic: multinucleated, polylobated
- Rare cases may have small, lymphoid appearing plasma cells or plasma cells with marked nuclear lobation
- Morphologic features:
- Mott cells / morula cells: multiple grape-like cytoplasmic inclusions comprised of crystalized Ig
- Russell bodies: hyaline intracytoplasmic and intranuclear inclusions
- Flame cells: vermillion staining glycogen rich IgA in cytoplasmic projections
- Gaucher-like cells / thesaurocytes: overstuffed fibrils
- Cytoplasmic crystals: occasional in myeloma, common in adult Fanconi syndrome
- Dutcher bodies: pale staining nuclear inclusions, single and usually large, more common in IgA myeloma
Cytology images
Contributed by Genevieve M. Crane, M.D., Ph.D.
Plasmacytoma touch preparation
Flow cytometry description
- Similar to plasma cell myeloma
Molecular / cytogenetics description
- In bone, genetics similar to plasma cell myeloma, extraosseous not extensively studied
Differential diagnosis
- Cutaneous or GI plasmacytoma:
- Particularly difficult to differentiate from marginal zone lymphoma, may not be possible
- Large cell lymphoma:
- With immunoblastic or plasmablastic features
- Marginal zone lymphoma, lymphoplasmacytic lymphoma:
- May have plasmacytoid features but more extensive sampling may reveal B cell component
- CD20 expression by lymphocytes or plasmacytoid cells
- Clonal B cell population by flow; molecular or cytogenetic features of marginal zone or lymphoplasmacytic lymphoma
- Plasma cell myeloma:
- Must be excluded by radiographs, bone marrow biopsy
- Radiographically, may mimic metastatic tumor, Langerhans cell histiocytosis
- Reactive plasma cell infiltrate:
Additional references
Board review style question #1
What is the best way to distinguish plasma cell myeloma from solitary plasmacytoma?
- CD19 expression
- Cytogenetics demonstrating a t(11;14) translocation
- Plasmablastic features
- Radiographs
Board review style answer #1
Board review style question #2
When considering the diagnosis of a solitary plasmactyoma in a cervical lymph node, which factor(s) are most important to consider?
- Lymph node involvement by myeloma
- Nodal marginal zone lymphoma with extensive plasmacytic differentiation
- Potential spread from the upper respiratory tract
- All of the above
Board review style answer #2
