Plasmacytoma is a plasma cell dyscrasia in which a plasma cell tumour grows within soft tissue or within the axial skeleton. The International Myeloma Working Group lists three types: 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. Signs and symptoms
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.
Left untreated, PF in animals is life-threatening, leading to not only loss of condition, but also secondary infection. PV is a very rare disorder described in pet dogs and cats. Paraneoplastic pemphigus has been identified in pet dogs. See also
List of conditions caused by problems with junctional proteins
List of cutaneous conditions
List of immunofluorescence findings for autoimmune bullous conditions
List of target antigens in pemphigus
Pemphigoid
Pemphigus herpetiformis

References
External links

National Organization of Rare Diseases: Pemphigus