WORKUP	Section 5 of 10
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Lab Studies:

• Solitary bone plasmacytoma

• Although levels are lower than in multiple myeloma, electrophoresis reveals a monoclonal protein in the serum or urine in 24-72% of patients (Knowling, 1983; Liebross, 1998; Brinch, 1990; Bolek, 1996; Jackson, 1990; Galieni, 1995; Holland, 1992; Frassica, 1989).

• Uninvolved immunoglobulin levels usually are within the reference range.

• Peripheral blood cell count, renal function, and calcium are within the reference range.

• Solitary extramedullary plasmacytoma

• Protein electrophoresis shows a monoclonal component in 14-25% of cases (Dimopoulos, 1999; Galieni, 2000; Liebross, 1999). In a series of 46 patients by Galieni and colleagues (2000), all patients had normal uninvolved immunoglobulins.

• Peripheral blood cell count, renal function, and calcium are within the reference range.

Imaging Studies:

• Solitary bone plasmacytoma

• On plain radiographs, SBP classically has a lytic appearance with clear margins and a narrow zone of transition to healthy surrounding bone (Dimopoulos, 2000). Rare occurrences of a cyst, a trabeculated lesion resembling a giant cell tumor or an aneurysmal bone cyst, and sclerotic lesions have been described (Huvos, 1992). The sclerotic lesion is associated with polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes (POEMS) syndrome (Miralles, 1992).

• On MRI, the SBP exhibits abnormal signal intensity (low on T1-weighted imaging and high on T2-weighted or short tau inversion recovery [STIR] images) that, in the appropriate clinical setting, is consistent with SBP (Moulopoulos, 1993).

• Solitary extramedullary plasmacytoma

• Radiographic assessment shows local bone destruction in most patients with nasal cavity or maxillary sinus involvement (Liebross, 1999).

• Computed tomography scan, MRI, and complete endoscopic examination of the aerodigestive and gastrointestinal tracts are required to determine the exact extent of the tumor and its potential for resectability (Alexiou, 1999).

• SBP: Biopsy of the lesion reveals infiltration of the bone by monoclonal plasma cells.

• SEP: Biopsy of the soft tissue lesion shows infiltration by monoclonal plasma cells.
  • In SEP, the soft tissue lesion commonly exhibits submucosal growth, requiring deep biopsy, open biopsy, or complete excision depending on tumor location (Alexiou, 1999).

  • Histologically, SEP may be classified as low, intermediate, or high grade (Susnerwala 1997).

  • Bone marrow biopsy shows less than 5% plasma cells without evidence of clonality (Galieni, 2000).

Staging:

• Wiltshaw (1976) classified soft tissue plasmacytoma into 3 clinical stages:

• Stage I - Limited to an extramedullary site

• Stage II - Involvement of regional lymph nodes

• Stage III - Multiple metastasis (although it is no longer a solitary plasmacytoma)

• The therapeutic and prognostic value of this classification needs further evaluation.

	TREATMENT	Section 6 of 10
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Medical Care:

• Solitary bone plasmacytoma

• Local radiotherapy is the treatment of choice (Dimopoulos, 2000; Dimopoulos, 1999; Liebross, 1998; Hu, 2000). Treatment fields should be designed to encompass all disease observed on MRI and should include a margin of healthy tissue (at least 2 cm). For spinal lesions, the margins should include at least 1 uninvolved vertebra.

• Local control is achieved in 88-100% of patients. Virtually all patients have major symptom relief (Hu, 2000) and a local tumor recurrence rate of approximately 10%.

• Most centers use approximately 40 Gy for spinal lesions and 45 Gy for other bone lesions. For lesions larger than 5 cm, 50 Gy should be considered.

• No dose-response relationship between radiation dose and disappearance of monoclonal protein was noted in a series of patients with solitary bone plasmacytoma as reported by Liebross et al (1998).

• Monoclonal protein is markedly reduced after radiotherapy in the majority of patients, but protein disappearance is observed in only 20-50% of patients (Alexiou, 1999).

• Surgery is contraindicated in the absence of structural instability or neurologic compromise (Soutar, 2004).

• Chemotherapy may be considered for patients not responding to radiation therapy. Regimens useful in multiple myeloma can be considered (Soutar, 2004).

• No role exists for adjuvant chemotherapy in SBP.

• Solitary extramedullary plasmacytoma

• Based on the documented radiation sensitivity of plasma cell tumors, the accepted treatment is radiotherapy.

• When a lesion can be completely resected, surgery provides the same results as radiotherapy.

• Combined therapy (surgery and radiotherapy) is an accepted treatment depending on the resectability of the lesion (Alexiou, 1999; Dimopoulos, 1999; Hu, 2000; Galieni, 2000; Liebross, 1999). In fact, combination treatment may provide the best results (Alexiou, 1999).

• The optimal dose for local control is 40-50 Gy (depending on tumor size) delivered over 4-6 weeks (Alexiou, 1999; Ho, 2000, Liebross, 1999).

• Because of the high rate of lymph node involvement, these areas should be included in the radiation field (Hu, 2000).

• Adjuvant radiotherapy should be recommended to patients with positive surgical margins.

• Chemotherapy may be considered for patients with refractory or relapsed disease. Regimens used for multiple myeloma can be considered (Soutar, 2004).

• Adjuvant chemotherapy may be considered for patients with tumors larger than 5 cm, as well as those with high-grade histology.

Surgical Care:

• Although surgical resection is not advised for the treatment of solitary bone plasmacytoma, spine instrumentation or another procedure sometimes is necessary to try to reestablish the normal architecture of the spine or other bone affected.

• If possible, a complete resection of the lesion, including lymph node dissection, should be attempted for soft tissue plasmacytomas.

Consultations:

• Orthopedic evaluation is recommended for patients with SBP because lesions may cause spinal cord compression syndrome or impending fractures. Therapeutic procedures, such as kyphoplasty, can be implemented in order to restore vertebral structure.

• An ear, nose, and throat evaluation is recommended for patients with SEP of the head and neck to precisely localize the lesion, obtain an adequate biopsy (including lymph nodes), and plan possible resection.

	MEDICATION	Section 7 of 10
Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Bibliography

No defined role exists for chemotherapy treatment of solitary bone plasmacytoma or soft tissue plasmacytoma, as mentioned above.

	MISCELLANEOUS	Section 9 of 10
Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Bibliography

Medical/Legal Pitfalls:

• Failure to diagnose spinal cord compression syndrome, pathologic and/or impending fractures can cause irreversible neurologic damage (eg, paraplegia, bowel or bladder dysfunction), chronic pain, or disabling musculoskeletal damage.

• Inappropriate follow-up or failure to evaluate progression to multiple myeloma delays institution of appropriate therapy to control the well-known systemic complications of multiple myeloma (eg, generalized bone destruction, hypercalcemia, anemia, hyperviscosity, infections, amyloid).