Vikram Deshpande, MD

G. Petur Nielsen, MD

Andrew E. Rosenberg, MD

Lateral radiograph of skull shows multiple lytic lesions. Note the small punched-out foci of lucency in the frontal and parietal areas. This is a characteristic appearance of multiple myeloma.

Gross photo shows a resected femoral head involved by plasmacytoma. Lesion is well demarcated from surrounding cancellous bone. Tumor is soft and hemorrhagic, & adjacent cancellous bone is free of tumor.



  • Plasma cell myeloma (PCM)


  • Plasma cell-based neoplasm composed of a clone of immunoglobulin-secreting, heavy-chain classswitched, terminally differentiated B cells that typically secrete a single homogeneous (monoclonal) immunoglobulin (Ig)

  • Plasma cell myeloma is a bone-marrow-based, multifocal malignant plasma cell neoplasm associated with M protein in serum &/or urine

  • Solitary plasmacytoma of bone is a localized malignant bone neoplasm consisting of monoclonal plasma cells

    • Complete skeletal radiographs show no other lesions

    • No clinical features of plasma cell myeloma and no evidence of bone marrow plasmacytosis except for solitary lesion



  • Incidence

    • Most common primary malignant bone tumor

  • Age

    • Patients usually > 30 years of age at time of diagnosis

      • Median age at diagnosis: ˜ 70 years

  • Gender

    • Males affected more frequently than females


  • May present as localized lesion (plasmacytoma) or as component of widespread disease (plasma cell myeloma)

  • May involve any bone

  • Most common sites are bones with active bone hematopoiesis

    • In order of frequency: Vertebrae, ribs, skull, pelvis, femur, clavicle, and scapula

    • Thoracic vertebrae are more commonly involved than cervical or lumbar

    • Long bone involvement below elbow or knee is rare


  • Pain

  • Pathologic fracture

Natural History

  • Plasma cell myeloma

    • Usually incurable, with survival ranging from 6 months to > 10 years and median survival of 3-4 years

  • Solitary plasmacytoma

    • 2/3 of patients eventually evolve to generalized myeloma or additional solitary or multiple plasmacytomas

    • 1/3 of patients remain disease free for > 10 years


  • Localized disease treated with resection or radiation

  • More disseminated disease is incurable, but treatment with combination of chemotherapy and radiation therapy may prolong survival

  • Bone marrow transplantation is option for younger patients


Radiographic Findings

  • Geographic lytic lesion centered in bone marrow without identifiable matrix

  • 44% show multiloculated appearance

  • Lesions in skull are well circumscribed and have punched-out appearance

  • Lesions of long bones are also usually well circumscribed and may be encompassed by periosteal new bone formation, giving the appearance of expansion

  • Rarely, myeloma generates sclerotic lesions

    • May occur in setting of POEMS syndrome

    • May appear normal or “cold” on isotope scans

MR Findings

  • T1WI: Low signal intensity soft tissue mass; enhancement with contrast

  • Fluid-sensitive sequences

    • Intermediate signal intensity soft tissue lesion


General Features

  • Friable, soft, and red

  • Underlying bone is eroded and fragile


Histologic Features

  • Tumoral mass of plasma cells displacing normal bone marrow elements

  • Myeloma plasma cells vary from mature forms indistinguishable from normal to immature, plasmablastic, and pleomorphic

    • Mature plasma cells

      • Eccentric nucleus with “spoke wheel” or “clockface” chromatin without nucleoli

      • Basophilic cytoplasm and perinuclear hof

    • Plasmablasts

      • Immature forms have more dispersed nuclear chromatin, higher nuclear:cytoplasmic ratio, and, often, prominent nucleoli

    • Pleomorphic

      • Nuclear immaturity and pleomorphism rarely occur in reactive plasma cells and are reliable indicators of neoplastic plasma cell myeloma

  • Cytoplasmic Ig may produce variety of morphologically distinctive findings

    • Multiple pale bluish-white, grape-like accumulations (Mott cells, Morula cells)

    • Cherry red refractive round bodies (Russell bodies)

    • Overstuffed fibrils (Gaucher-like cells)

    • Crystalline rods; pathognomonic of myeloma



  • CD138, CD38 are reliable markers of plasma cells

  • IHC &/or ISH for light chains shows either kappa- or lambda-light chain-restricted plasma cell population

  • CD19 is negative

  • May aberrantly express CD56, CD117, CD20, and CD10


  • Both numerical and structural chromosomal abnormalities are common

  • Most frequent chromosome translocations involve the heavy chain locus on chromosome 14q32


Metastatic Carcinoma and Lymphoma

  • Poorly differentiated neoplastic cells may mimic other poorly differentiated tumors

    • Problematic on frozen sections; however, diagnosis can usually be readily made on touch preps

Jul 6, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Plasmacytoma/Myeloma

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