International Myeloma Working Group Recommendations for the Diagnosis and Management of Solitary Plasmacytomas

E Efstathios Kastritis S Shaji K. Kumar (Division of Hematology, Mayo Clinic, Rochester, MN) V Vincent S. Rajkumar (Division of Hematology, Mayo Clinic, Rochester, MN) W Wee Joo Chng L Luciano Costa (42Division of Hematology and Oncology, University of Alabama at Birmingham, Birmingham, United States) M Monika Engelhardt W Wilson Gonsalves (1Mayo Clinic, Rochester, United States) V Vania Hungria (Clinica São Germano, São Paulo) J Jens Hillengass (Roswell Park Comprehensive Cancer Center) D Dragan Jevremovic (1Mayo Clinic, Rochester, United States) E Eirini Katodritou (Theagenio Cancer Hospital, Thessaloniki, Greece) S Sigurður Yngvi Kristinsson S Sagar Lonial (Emory University, Atlanta) H Heinz Ludwig P Philip McCarthy (8Roswell Park Comprehensive Cancer Center, Buffalo, United States) E Elias Mai (Heidelberg Myeloma Center, Internal Medicine V, Hematology, Oncology and Rheumatology, Heidelberg University Hospital, Heidelberg, Germany) S Salomon Manier T Tom Martin (UCSF Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA) M María-Victoria Mateos H Hira Mian (Department of Oncology, McMaster University, Hamilton, ON, Canada) J Joseph Mikhael (2Translational Genomics Research Institute, City of Hope Cancer Center, Phoenix, United States) P Philippe Moreau N Nikhil C. Munshi B Bruno Paiva C Charlotte Pawlyn L Leo Rasche (University Hospital of Würzburg, Würzburg, Germany) J Joshua Richter (Mount Sinai Medical Center, New York) J Jesus San Miguel (5Cancer Center Clinica Universidad de Navarra, Centro de Investigación Médica Aplicada Universidad de Navarra, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain) D Douglas W. Sborov (5Huntsman Cancer Institute, The University of Utah, Salt Lake City, UT) S Saad Z. Usmani (Memorial Sloan Kettering Cancer Center, New York) M Meletios A. Dimopoulos E Elena Zamagni

Abstract

Solitary plasmacytomas (SPs) are rare localized tumors of clonal plasma cells, either in the bone (solitary bone plasmacytoma) or in soft tissue/extraosseous (extramedullary) with either no or with minimal bone marrow (BM) infiltration (<10% clonal plasma cells by immunohistochemistry) and no evidence of systemic involvement or myeloma defining events. Approximately 50% of SPs will progress to symptomatic myeloma within 5 years after initial definitive local radiotherapy. Increased availability of improved diagnostic and monitoring tools has increased the sensitivity of detection of additional lesions and marrow involvement and has implications for the follow-up strategy after treatment. Thus, the definitions and requirements for the diagnosis and follow-up of SPs are evolving. The diagnosis of SP requires the careful exclusion of multiple myeloma (MM) that would require systemic therapy, by using all the available methods to detect systemic disease (advanced imaging, sensitive BM assessment methods, blood and urine tests). Local radiotherapy remains the mainstay of therapy, and despite the availability of innovative drugs for MM, the clinical benefit of systemic therapy currently remains poorly defined. The International Myeloma Working Group provides here updated recommendations for the diagnosis, evaluation, treatment, and response assessment of patients with SPs, incorporating recent data and advances in diagnostic tools.

Article Details

Volume / Issue Vol. 1, Issue 1
Published July 22, 2026
ISSN 0732-183X
Publisher Lippincott Williams & Wilkins

Journal Info

Journal of Clinical Oncology

Lippincott Williams & Wilkins

ISSN: 0732-183X Health Sciences

Authors (32)

E

Efstathios Kastritis

S

Shaji K. Kumar

Division of Hematology, Mayo Clinic, Rochester, MN

V

Vincent S. Rajkumar

Division of Hematology, Mayo Clinic, Rochester, MN

W

Wee Joo Chng

L

Luciano Costa

42Division of Hematology and Oncology, University of Alabama at Birmingham, Birmingham, United States

M

Monika Engelhardt

W

Wilson Gonsalves

1Mayo Clinic, Rochester, United States

V

Vania Hungria

Clinica São Germano, São Paulo

J

Jens Hillengass

Roswell Park Comprehensive Cancer Center

D

Dragan Jevremovic

1Mayo Clinic, Rochester, United States

E

Eirini Katodritou

Theagenio Cancer Hospital, Thessaloniki, Greece

S

Sigurður Yngvi Kristinsson

S

Sagar Lonial

Emory University, Atlanta

H

Heinz Ludwig

P

Philip McCarthy

8Roswell Park Comprehensive Cancer Center, Buffalo, United States

E

Elias Mai

Heidelberg Myeloma Center, Internal Medicine V, Hematology, Oncology and Rheumatology, Heidelberg University Hospital, Heidelberg, Germany

S

Salomon Manier

T

Tom Martin

UCSF Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA

M

María-Victoria Mateos

H

Hira Mian

Department of Oncology, McMaster University, Hamilton, ON, Canada

J

Joseph Mikhael

2Translational Genomics Research Institute, City of Hope Cancer Center, Phoenix, United States

P

Philippe Moreau

N

Nikhil C. Munshi

B

Bruno Paiva

C

Charlotte Pawlyn

L

Leo Rasche

University Hospital of Würzburg, Würzburg, Germany

J

Joshua Richter

Mount Sinai Medical Center, New York

J

Jesus San Miguel

5Cancer Center Clinica Universidad de Navarra, Centro de Investigación Médica Aplicada Universidad de Navarra, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain

D

Douglas W. Sborov

5Huntsman Cancer Institute, The University of Utah, Salt Lake City, UT

S

Saad Z. Usmani

Memorial Sloan Kettering Cancer Center, New York

M

Meletios A. Dimopoulos

E

Elena Zamagni