Plasmacytoma

Plasmacytoma
Micrograph of a plasmacytoma. H&E stain.
Classification and external resources
Specialty	Hematology and oncology
ICD-10	C90.2
ICD-9-CM	238.6
ICD-O	M9731/3, M9734/3
DiseasesDB	8628
eMedicine	med/2532
MeSH	D010954
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Plasmacytoma refers to plasma cell tumor growing within soft tissue or within the axial skeleton. There are three distind by the International Myeloma Working Group: solitary plasmacytoma of bone (SPB), extramedullary plasmacytoma (EP) and multiple plasmacytomas that are either primary or recurrent. The most common of these is SPB, accounting for 3–5% of all plasma cell malignancies. SPBs occur as lytic lesions within the axial skeleton and extramedullary plasmacytomas most often occur in the upper respiratory tract (85%), but can occur in any soft tissue. Approximately half of all cases produce paraproteinemia. SPBs and extramedullary plasmacytomas are mostly treated with radiotherapy, but surgery is used in some cases of extramedullary plasmacytoma. The skeletal forms frequently progress to multiple myeloma over the course of 2–4 years. Due to their cellular similarity, plasmacytomas have to be differentiated from multiple myeloma. For SPB and extramedullary plasmacytoma the distinction is the presence of only one lesion (either in bone or soft tissue), normal bone marrow (<5% plasma cells), normal skeletal survey, absent or low paraprotein and no end organ damage.

There can be some ambiguity when using the word. "Plasmacytoma" is sometimes equated with "plasma cell dyscrasia" or "solitary myeloma". It is often used as part of the phrase "solitary plasmacytoma". or as part of the phrase "extramedullary plasmacytoma". In this context, "extramedullary" means outside of the bone marrow.

For SPB the most common presenting symptom is that of pain in the affected bone. Back pain and other consequences of the bone lesion may occur such as spinal cord compression or pathological fracture. Around 85% of extramedullary plasmacytoma presents within the upper respiratory tract mucosa, causing possible symptoms such as epistaxis, rhinorrhoea and nasal obstruction. In some tissues it may be found as a palpable mass.

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