Page 1123 - Clinical Immunology_ Principles and Practice ( PDFDrive )

ChaPter 80 Monoclonal Gammopathies 1087

measurable disease in serum or urine using the following anemia or renal insufficiency attributable to the underlying plasma
parameters: serum M-protein <1 g/dL and urine M-protein cell disorder.
<200 mg/24 hours. 6
Monitoring these patients is difficult using the standard serum Diagnosis
and urine electrophoretic tests. In most of these patients, the The diagnosis of SPB requires the following: biopsy-proven
serum FLC assay can be used to monitor the disease, provided solitary tumor of bone with evidence of clonal plasma cells,
that the serum FLC ratio is abnormal and the involved (affected) metastatic bone survey and either CT (PET/CT) or MRI of the
FLC level is ≥10 mg/dL. Patients with oligosecretory disease spine and pelvis showing no other lytic lesions, bone marrow
may need to be monitored with imaging and bone marrow aspirate, and biopsy that contains no clonal plasma cells as well
studies, particularly if the baseline FLC levels are unmeasurable as no findings attributable to clonal plasma cell proliferative
8
(<10 mg/dL). disorder (anemia, hypercalcemia, or renal insufficiency). The
presence of an M-protein does not exclude the diagnosis of SPB,
PLASMA CELL LEUKEMIA as a low level of M-protein may be present in 30–75% of cases.
This M-protein may or may not disappear with treatment.
PCL is a very rare and aggressive variant of MM. It is characterized
by high levels of plasma cells circulating in peripheral blood. Management and Prognosis
PCL may originate de novo (primary PCL) or as a secondary The primary treatment for patients with SPB is localized radiation
transformation of MM (secondary PCL). The incidence of PCL therapy (RT). Surgery may be required for patients with structural
in Europe has been estimated at 4 cases/10 000 000 persons/year. instability of the bone, retropulsed bone, or rapidly progressive
Secondary PCL occurs as a progression of disease in 1–4% of symptoms from cord compression. Bisphosphonates are not
all cases of MM. 13 recommended for patients with SPB, except in the setting of
underlying osteopenia. 14
Clinical Presentation and Diagnosis The median overall survival of patients with SPB is approxi-
Patients with PCL typically present with signs and symptoms mately 10 years. Overall survival rates at 5 and 10 years are
13
similar to those seen in MM as well as in other leukemias. The approximately 75% and 45%, respectively, with corresponding
diagnosis of PCL is based upon the evaluation of peripheral disease-free survival rates of 45% and 25%. A little more than
blood smear, bone marrow aspirate and biopsy, and protein half of patients with SPB will eventually develop overt MM.
electrophoresis. PCL diagnosis is confirmed when a monoclonal Patients with true SPB who meet the strict criteria listed above
population of plasma cells is present in the peripheral blood have a recurrence/progression rate of approximately 10% within
with an absolute plasma cell count exceeding 2000/µL and 20% 3 years. 14
of the peripheral blood white cells. 13
Management and Prognosis SOLITARY EXTRAMEDULLARY PLASMACYTOMA
Treatment generally consists of induction therapy followed by SEPs are plasma cell tumors that arise outside the bone marrow.
HSCT, if eligible for HSCT, and chemotherapy alone for those SEP refers to a solitary nonosseous plasma cell neoplasm in the
13
ineligible for HSCT. The prognosis of PCL is poor with a median absence of any other sign of MM. The SEP lesions are most
survival of 7–11 months. Median survival for PCL occurring often located in the head and neck region, mainly in the upper
after refractory or relapsing MM is 2–7 months. 13 aerodigestive tract, but may also occur in the gastrointestinal
tract, urinary bladder, central nervous system, thyroid, breast,
SOLITARY PLASMACYTOMA OF BONE testes, parotid gland, lymph nodes, and skin. The median age at
diagnosis for SEP is 55 to 60 years; approximately two-thirds of
SPB is a localized tumor in the bone comprised of a single clone patients are male, and SEP accounts for approximately 3% of
of plasma cells in the absence of other features of MM. Approxi- plasma cell malignancies. 15
mately 5% of all cases of plasma cell disorders are SPB. The
incidence of SPB is approximately 0.15 cases/100 000 person-years Clinical Presentation
with approximately 450 new cases per year in the United States. Most patients present with symptoms related to the location of
The incidence is highest in patients of African background and the mass. Approximately 80% involve the upper respiratory tract
lowest in Asians and Pacific Islanders. Men are diagnosed twice (i.e., oronasopharynx and paranasal sinuses) and cause epistaxis,
as frequently as women. The median age at diagnosis is 55–65 nasal discharge, or nasal obstruction. Less common sites of
years compared with a median age at diagnosis of 71 years for involvement include the gastrointestinal tract, liver, lymph nodes,
patients with MM. 14 testes, skin, and central nervous system. Primary plasmacytoma
of the lung often presents as a pulmonary nodule or hilar mass
Clinical Presentation with or without hemoptysis. 15
Most patients present with skeletal pain or a pathological fracture
of the affected bone. Patients with vertebral involvement may Diagnosis
have severe back pain or neurological compromise. Less com- By definition, patients with SEP do not have anemia, hypercal-
monly, SPB can extend into the surrounding soft tissue, resulting cemia, renal insufficiency, or bone lesions attributable to the
in a palpable mass. The most common bones involved are those underlying plasma cell disorder. The diagnosis of SEP requires
with active hematopoiesis; the axial skeleton is more commonly the following: biopsy-proven extramedullary tumor with evidence
involved than is the appendicular skeleton, and involvement of of clonal plasma cells, metastatic bone survey and either MRI
the distal appendicular skeleton below the knees or elbows is or PET/CT of the spine and pelvis that show no lytic lesions,
14
extremely rare. By definition, patients with SPB do not have bone marrow aspirate and biopsy without clonal plasma cells,