EMP—Extramedullary plasmacytoma

Solitary Plasmacytoma: Medullary and Extramedullary

A diagnosis of solitary plasmacytoma requires fulfillment of each of the following criteria: histologic confirmation of clonal plasma cells at a single site; a negative bone marrow with absence of a clonal plasmacytosis; no distant bone involvement; and no anemia, hypercalcemia, or renal impairment (Table 86.1). The solitary plasmacytoma could present as a single bony lesion (medullary) or in soft tissue outside the bone (extramedullary). A solitary plasmacytoma of the bone is 40% more common than an extramedullary soft tissue plasmacytoma. Solitary plasmacytoma of the bone is most commonly encountered in the axial skeleton (skull, spine, pelvis, ribs, and sternum), accounting for 80% of cases; upper and lower extremities account for 15% of cases. Extramedullary soft tissue plasmacytomas are often associated with the mucosal area of the upper aerodigestive passages (80%).

Solitary plasmacytomas are rather uncommon and account for 6% of plasma cell neoplasms. The incidence is 0.3 per 100,000 person-years in United States. Similarly to MM, the incidence of solitary plasmacytomas increases with age; however, the median age of diagnosis was 62 years for extramedullary plasmacytomas and 65 years for solitary bone plasmacytoma as compared with median age of onset at 71 years for MM in the National Cancer Institute Surveillance, Epidemiology, and End Results program (SEER) data. The incidence of solitary plasmacytoma increased by 10% in 1999–2004 relative to 1992–2008, whereas the incidence of MM declined by 3% during the same period.

Patients presenting with solitary plasmacytomas require a complete workup to confirm the diagnosis. They should undergo serum protein electrophoresis, serum immunofixation, serum free light chain assay, urine protein electrophoresis, urine immunofixation, a diagnostic bone marrow aspiration and biopsy with flow cytometry to detect clonal plasma cells, and detailed skeletal imaging that should include either PET-CT or a skeletal survey and MRI of the spine and pelvis. One-third of the patients may present with a detectable monoclonal paraprotein in the serum or urine or both. Persistence of the monoclonal paraprotein after local treatment is predictive of a recurrence of MM. Patients with less than 10% plasma cells in the bone marrow biopsy may be managed with therapies directed against the solitary lesion initially. However, these patients will also progress to MM over the subsequent years of follow-up.

Solitary plasmacytomas are generally treated with local radiation therapy at a dose of 40–50 Gy. Depending upon the location, small extramedullary soft tissue plasmacytomas may be treated with excision biopsy alone. Solitary plasmacytomas of the bone may require surgical intervention for stabilization followed by local radiation therapy.

The disease-free survival at 10 years is 63% for patients with solitary plasmacytomas. The disease-specific survival seems to plateau at about 80% for extramedullary plasmacytomas, compared with 50% for solitary bone plasmacytomas. Less than one-third of solitary extramedullary plasmacytoma patients died as a result of myeloma, as compared with 58% of the patients with solitary bone plasmacytomas. Progression to myeloma generally occurs within 5 years from initial diagnosis. Patients presenting with medullary plasmacytomas, patients with persistence of a monoclonal paraprotein after treatment for the solitary plasmacytoma, patients with detectable low levels of clonal plasma cells in the bone marrow, patients between 40 and 60 years of age, and patients of African American descent are at higher risk for progression to MM. These patients should be followed closely for the next 5 years.

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Plasma Cell Disorders

S. Vincent Rajkumar, in Goldman's Cecil Medicine (Twenty Fourth Edition), 2012

Extramedullary Plasmacytoma

Extramedullary plasmacytomas outside the bone marrow are most commonly found in the upper respiratory tract (80% of cases), especially in the nasal cavity and sinuses, nasopharynx, and larynx. Extramedullary plasmacytomas may also occur in the gastrointestinal tract, central nervous system, urinary bladder, thyroid, breast, testes, parotid gland, or lymph nodes. Extramedullary plasmacytomas may be solitary, or they may occur in the context of existing myeloma. The diagnosis of solitary extramedullary plasmacytoma is based on detection of a plasma cell tumor in an extramedullary site, absence of clonal plasma cells on bone marrow examination, and absence of other bony or extramedullary lesions on radiographic studies. Treatment of solitary extramedullary plasmacytoma consists of either complete surgical resection or tumoricidal irradiation. The plasmacytoma may recur locally, metastasize to regional nodes, or, rarely, develop into multiple myeloma.

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Central Nervous System Tumors

MAHLON D. JOHNSON, JAMES B. ATKINSON, in Modern Surgical Pathology (Second Edition), 2009

Plasmacytoma

CLINICAL PRESENTATION

Plasma cell neoplasms rarely involve the CNS as dura-based lesions.296 On T1-weighted images, the tumor exhibits intermediate signal compared with brain, with marked enhancement after the administration of gadolinium. On T2-weighted images, plasmacytomas are isointense with gray matter.

HISTOPATHOLOGY

Histologically, they are identical to plasmacytomas elsewhere. Usually, their homogeneity and monoclonal immunophenotype differentiate plasmacytoma from both granuloma and meningioma (Fig. 51-39).

DIFFERENTIAL DIAGNOSIS

Plasmacytomas must be differentiated from plasma cell granulomas, which may also present as dura-based lesions (see later). Because plasmacytomas may contain leptomeninges, they must also be differentiated from lymphoplasmacytic meningioma. Their recognition and differentiation from surgically managable plasmacytic meningioma is important because radiation and chemotherapy after surgical resection offer a potential cure.317

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Nonpituitary Tumors of the Sellar Region

Olga Moshkin, ... Kalman Kovacs, in The Pituitary (Third Edition), 2011

Plasmacytoma

Plasmacytomas can involve the sella and simulate nonfunctioning pituitary adenomas clinically. Most of the patients reported eventually developed full-blown multiple myeloma [182–184]; only very few cases can be considered as true solitary sellar plasmacytomas [185]. Histologically, a plasmacytoma composed of relatively well-differentiated plasma cells can be mistaken for a chromophobe adenoma [186]. However, electron microscopy and immunohistochemistry will demonstrate lack of epithelial and neurosecretory features. Furthermore, clonal rearrangements of immunoglobulin genes typical of B-cell neoplasms can be demonstrated in plasmacytomas by molecular genetic studies.

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Plasmacytomas in Mice

M. Potter, in Encyclopedia of Genetics, 2001

Spontaneous PCTGEN in Genetically Altered Mice

Plasma cell tumors develop spontaneously with high incidence in intact, nonpristane-treated mice carrying in E μ-ν-abl transgene. The strains of mice used in which this transgene has been effective include strains that are resistant to pristane PCTGEN. The PCTs developing in this transgenic mouse carry t(12;15) translocations. Transgenic mice carrying a human IL-6 transgene under the control of the H-2LD promoter develop PCTs.

Plasma cell tumors have been observed in 2–7% of (SJL×C57BL)F2 mice carrying Eμ-bcl-2 transgenes. Furthermore, PCTs can be induced with high incidence in BALB/c.Eu-bcl-2-22 mice with pristane.

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Neurologic Aspects of Systemic Disease Part II

Urszula Sobol, Patrick Stiff, in Handbook of Clinical Neurology, 2014

Solitary plasmacytoma

Solitary plasmacytoma (plasma cell tumor) is the only known potentially curable plasma cell disorder. It can arise in bone or soft tissue. When it is confined to bone it is categorized as solitary bone plasmacytoma (also known as intramedullary plasmacytoma or osteosclerotic myeloma); when it occurs in soft tissue sites (most commonly the upper respiratory tract but also CNS, gastrointestinal tract, bladder, thyroid, breast, testes, parotid gland, and lymph nodes) it is called extramedullary plasmacytoma (Rajkumar et al., 2006). In patients with plasma cell disorders, the incidence of solitary plasmacytoma is only 3–5% (International Myeloma Working Group, 2003). The diagnosis is confirmed by biopsy-proven solitary lesion of bone or soft tissue with clonal plasma cells but normal bone marrow with no clonal plasma cells, normal skeletal survey, and MRI of spine/pelvis and no evidence of end organ damage (anemia, hypercalcemia, renal failure, or additional lytic bone lesion) (Rajkumar et al., 2006). Patients with solitary plasmacytoma are at risk of progression to multiple myeloma (with higher progression rate in patients with solitary bone plasmacytoma as opposed to extramedullary plasmacytoma). Patients with solitary bone plasmacytomas may also have systemic manifestations such as POEMS syndrome (described below).

Solitary plasmacytoma, a potentially curable plasma cell disorder, is in contrast to multiple plasmacytomas, which tend to occur in late stages of the disease and in high-risk MM (as defined by Table 73.5). Radiation therapy alone may be a treatment option for solitary plasmacytoma but systemic therapy is indicated in patients with multiple plasmacytomas and MM.

Neurologic complications from plasmacytomas can vary depending on the location of mass effect (spinal cord versus intracranial), as described above.

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Hematologic Disorders

Brad W. Neville DDS, ... Angela C. Chi DMD, in Color Atlas of Oral and Maxillofacial Diseases, 2019

Fig. 13.22

The plasmacytoma represents a monoclonal proliferation of neoplastic plasma cells at only one anatomic site; however, these lesions have the capability eventually to evolve into multiple myeloma. Plasmacytomas comprise only 5% of plasma cell neoplasms and can develop either within bone or in soft tissue, the latter being identified as extramedullary plasmacytoma. This lesion affects men approximately twice as frequently as women, and it is typically diagnosed approximately 10 years earlier than multiple myeloma. Solitary plasmacytoma of bone is found most commonly in the vertebrae, whereas the majority of extramedullary plasmacytomas affect the upper respiratory tract, including the oral cavity. For plasmacytoma of bone, bone pain is the often the presenting symptom, whereas extramedullary plasmacytoma will present as a soft tissue swelling.

The most common treatment is localized radiation therapy, but curettage and/or systemic chemotherapy also may be used. Initial control of the disease is typically seen, with nearly 95% showing apparent elimination of the tumor; however, this often is not a permanent cure. Regardless of the treatment, progression to multiple myeloma occurs for approximately 60% of patients whose plasmacytomas arise within bone. However, extramedullary plasmacytomas transform into multiple myeloma in only approximately 5% of cases.

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Bone Marrow, Blood Cells, and the Lymphoid/Lymphatic System1

Katie M. Boes, Amy C. Durham, in Pathologic Basis of Veterinary Disease (Sixth Edition), 2017

Extramedullary Plasmacytomas.

Extramedullary plasmacytomas are most commonly diagnosed in the skin of dogs (also cats and horses), where they constitute 1.5% of all canine cutaneous tumors (see Chapter 17). The pinnae, lips, digits, and chin are the most commonly affected locations, and most lesions are solitary, though multiple plasmacytomas are infrequently diagnosed. Other tissues affected include the oral cavity, intestine (colorectal in particular), liver, spleen, kidney, lung, and brain; of these, the oral cavity and intestine (colorectal) are involved most often. In one study, extramedullary plasmacytomas represented 5% of all canine oral tumors and 28% of all extramedullary plasmacytomas diagnosed. Most cutaneous extramedullary plasmacytomas are benign, and complete excision is usually curative; oral cavity and colorectal extramedullary plasmacytomas are likely to behave in a similar manner. More aggressive forms may occur at any site.

As with multiple myeloma, the neoplastic cells composing the tumor may vary from well differentiated to pleomorphic, often within the same tumor. The cells often have a characteristic perinuclear Golgi clearing or "halo," and the more pleomorphic cells exhibit karyomegaly and binucleation (Fig. 13-84). Extramedullary plasmacytomas may produce monoclonal immunoglobulins with resulting monoclonal gammopathy. Amyloid deposition (which may mineralize) is also observed in a proportion of cases. Differentiation from other round cell tumors may be aided by immunohistochemistry (MUM1/IRF4 is particularly sensitive and specific for plasma cell neoplasms).

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Plasma Cell Neoplasms

Faramarz Naeim, ... Wayne W. Grody, in Atlas of Hematopathology, 2013

Extramedullary Plasmacytoma

Extramedullary plasmacytoma is a monoclonal plasma cell neoplasm that arises outside the bone marrow. The most frequent site of involvement is the upper respiratory tract, including the nasal cavity and sinuses, nasopharynx, and larynx, but any organ or tissue may be involved, such as gastrointestinal tract and urinary tracts, thyroid, male and female reproductive systems, parotid gland, lymph nodes, testicles, and central nervous system (Figures 41.31 and 41.32). The diagnosis is made based on the monoclonality of the plasma cell tumor and lack of evidence for PCM and serum or urine M-protein. IgA is the most frequent immunophenotype, but again it is IgM that is typically assessed at the molecular level for monoclonality. Approximately 15% of the patients may eventually develop symptomatic PCM. Surgery and/or radiation are the treatments of choice.

Figure 41.31. Solitary plasmacytoma of conjuctiva.

Biopsy section demonstrating a large aggregate of plasma cells (A, low power; B, intermediate power). Immunohistochemical stains for CD138 (C) and kappa light chain (D) demonstrate a monoclonal population of plasma cells.

Courtesy of G. Pezeshkpour, M.D., Department of Pathology, VA Greater Los Angeles Healthcare System.

Figure 41.32. Plasmablastic plasmacytoma of testis.

Biopsy section (A, low power; B, intermediate power; and C, high power). The neoplastic cells express CD138 (D), lambda light chain (E, red) and KI67 (F).

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Nonsquamous Pathologic Diseases of the Hypopharynx, Larynx, and Trachea

Margaret S. Brandwein-Gensler, ... Douglas R. Gnepp, in Diagnostic Surgical Pathology of the Head and Neck (Second Edition), 2009

Clinical Features

Most EMPs (80%) occur in the head and neck. Approximately 80% of head and neck EMPs are primary tumors and 20% are secondary to myeloma.352 The mean age of patients is 59 years (range, 34–78 years) with a male predominance of 4:1. Approximately 80% occur in the sinonasal tract and Waldeyer's ring. The larynx is involved in 5% and the pharynx in 5% of cases. Most EMPs are solitary (2–5 cm), and 10% are multiple at presentation. On examination, mucosal EMPs appear as polypoid, smooth, submucosal masses. Laryngeal EMPs generally involve the supraglottis; usually the epiglottis followed by the false cord, ventricle, and arytenoid.353–355 Subglottic plasmacytomas are less common and may arise from the cricoid marrow space and hence technically are not extramedullary.356 Cervical lymph adenopathy is present in 10% of patients. The extent of primary tumor is best determined on radiographic imaging. The diagnosis usually requires biopsy of the mass.

Gorenstein and colleagues354 described six men with solitary EMP of the larynx, ranging in age from 32 to 63 years (mean, 53 years). The first symptom was usually hoarseness. The vocal cord was the site in four and the subglottis in two cases. In three cases, there was also involvement of the adjacent ventricle, trachea, or base of the tongue. Most were well-differentiated EMPs.

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