Overview and definition
Plasmablastic lymphoma (PBL) is an aggressive, usually CD20-negative large B-cell lymphoma with plasmablastic morphology and a terminal plasma-cell immunophenotype, occupying a biologic space between diffuse large B-cell lymphoma (DLBCL) and plasma cell myeloma.[1][2] It was first defined in the oral cavity, which remains its signature extranodal site, and it is strongly linked to immunodeficiency—particularly HIV infection—and to Epstein–Barr virus (EBV).[1][3] In the jaws it behaves as a primary soft-tissue tumor of the gingiva, alveolar ridge, or palate that secondarily invades bone, producing an ill-defined osteolytic defect beneath a rapidly enlarging, often ulcerated mucosal mass.[4] The disease is clinically aggressive with frequent chemoresistance; management centers on intensive multiagent chemotherapy rather than surgery, and overall prognosis remains poor.[2][3]
Terminology and classification
PBL is recognized by the World Health Organization classification as a distinct CD20-negative aggressive B-cell (large B-cell) lymphoma.[1] The entity was delineated by Delecluse and colleagues in 1997 from a series of HIV-positive patients with oral tumors.[1] Useful descriptive terms include oral PBL and AIDS-related/HIV-related PBL, reflecting its archetypal clinical context; "plasmablastic lymphoma of the oral mucosa type" refers to the original immunodeficiency-associated oral presentation. The most important terminologic pitfall is separation from plasma cell neoplasms with plasmablastic morphology (plasmablastic/anaplastic myeloma or extramedullary plasmacytoma), which are morphologically and immunophenotypically near-identical and are distinguished by clinical and serologic correlation rather than by histology alone.[1][5]
Epidemiology
PBL is rare, with roughly 120 new cases diagnosed annually in the United States, representing less than 1% of DLBCL and an estimated 2% of HIV-related lymphomas.[1][2] There is a consistent male predominance of approximately 3:1.[4][6] Patients are typically adults, with a younger median age than DLBCL, NOS; oral series report medians near 41–48 years, and HIV-positive patients present younger than HIV-negative patients.[1][4][6]
- Immune status: Most oral cases are HIV-positive—reported at 84% in one pooled oral series and 100% in several single-center oral cohorts—often with uncontrolled infection and low CD4 counts at diagnosis. PBL also arises after solid-organ transplantation, in autoimmune or iatrogenic immunosuppression, and in otherwise immunocompetent (frequently elderly) individuals.[1][4][5][6]
- EBV: Detectable in roughly two-thirds of cases overall and in essentially all cases of some HIV-endemic oral cohorts.[6][7]
- Anatomic distribution: The oral cavity is the most frequent extranodal site; within it the gingiva/alveolar ridge is most common, followed by the palate. The maxilla is involved more often than the mandible, with a posterior-region predilection.[4][8]
Clinical presentation
Oral PBL typically presents as a rapidly growing swelling or proliferative mass of the gingiva, alveolar ridge, or palate, frequently ulcerated, friable, and prone to bleeding; some lesions are submucosal nodules with normal overlying mucosa.[4] Pain is variable, and the tumor may be painless despite considerable size.[4] Common accompanying findings include pathologic mobility of adjacent teeth, a non-healing extraction socket, and lesions that appear or accelerate after dental extraction or biopsy.[4]
The tempo is aggressive, with many patients reporting symptom duration of only weeks.[9] Because early lesions mimic an odontogenic abscess, periapical infection, or epulis, cases are commonly treated initially with antibiotics, endodontics, or extraction, delaying diagnosis.[10][11] Constitutional B symptoms (fever, night sweats, weight loss) are reported in a sizable minority to majority depending on cohort, and extension to cervical nodes or distant sites occurs.[4]
Red flags warranting prompt biopsy include a non-healing socket, a gingival/palatal mass that enlarges over weeks, numbness or paresthesia without dental cause, and any "inflammatory" lesion failing to respond to conventional dental therapy.[12][13]
Radiographic findings
The dominant radiographic theme is an ill-defined osteolytic jaw defect underlying a soft-tissue mass, reflecting a tumor that originates in mucosa/gingiva and invades bone secondarily.[4]
Location and distribution
Lesions center on the alveolar ridge, with the maxilla more frequently affected than the mandible and a predilection for the posterior jaws; the hard palate is the next most common site.[4] Maxillary lesions may encroach on the maxillary sinus, nasal cavity, and orbital floor.[14]
Relationship to teeth and the alveolar process
Osseous change ranges from localized alveolar/periodontal bone loss around one or more teeth to a large destructive defect.[4] Reported tooth-related findings include loss of lamina dura, widened periodontal ligament space, periapical radiolucency, and a "floating tooth" appearance as alveolar support is destroyed.[14] These dentally centered patterns closely simulate inflammatory periapical/periodontal disease.[14]
Periphery and shape
Borders are poorly demarcated/ill-defined in the large majority (reported near 93% of oral cases), though occasional well-demarcated lesions occur and can mimic a cyst.[4]
Internal architecture
The lesion is radiolucent/osteolytic without a formed internal matrix or septation; intratumoral calcification is only rarely described.[4]
Effects on teeth and adjacent structures
The characteristic effect is cortical erosion and destruction rather than cortical expansion, typically with an associated soft-tissue mass; cortical disruption has been observed in essentially all plasmablastic cases in a jaw-lesion systematic review.[14] Root resorption and periosteal reaction are generally not reported and, when periosteal change is found in jaw lymphomas broadly, it is uncommon—so marked resorption or exuberant periosteal new bone should prompt reconsideration of the diagnosis.[4][14]
Growth pattern and extent
Growth is rapid and permeative, with crossing of anatomic planes in more aggressive lesions and extension into sinus, orbit, or facial soft tissues.[4][14] The combination of a soft-tissue–predominant mass, cortical destruction without expansion, and absence of root resorption helps separate PBL from the punched-out intraosseous lysis of myeloma, the expansile intraosseous lesion of solitary plasmacytoma, and cystic lesions.[14]
Other imaging findings
Cross-sectional and metabolic imaging materially refine extent and stage and should be obtained when PBL is suspected.
Soft-tissue extent
On magnetic resonance imaging the mass shows variable T1/T2 signal with contrast enhancement; low apparent diffusion coefficient reflects high cellularity and supports a malignant, highly cellular process, and dynamic contrast kinetics in head-and-neck lymphoma typically show a lower peak enhancement index than squamous cell carcinoma.[4]
Staging and metabolic activity
PBL is FDG-avid, so fluorodeoxyglucose positron-emission tomography combined with cross-sectional imaging is valuable for staging, baseline reference, and response assessment.[4]
Differential diagnosis
Because jaw PBL mimics both inflammatory dental disease and other malignancies, the differential spans infection, carcinoma, and plasma-cell/lymphoid neoplasia; discrimination rests on biopsy with a full immunophenotype plus clinical and serologic correlation.[4][15]
| Entity | Why it is considered | Best discriminator |
|---|---|---|
| Odontogenic infection / osteomyelitis | Ill-defined lucency, pain, swelling, non-healing socket mimic PBL; most cases initially misread as inflammatory | Failure to respond to antibiotics/extraction and a dominant soft-tissue mass should trigger biopsy[13][14] |
| Gingival/alveolar squamous cell carcinoma | Ulcerated destructive maxillary/mandibular mass with cortical erosion; often provisionally diagnosed as carcinoma | Cytokeratin (AE1/AE3) and p40/p63 positivity with MUM1/IRF4-negative tumor cells favor SCC; both SCC and PBL can express CD138 and EMA[15][16][17] |
| Plasma cell myeloma / extramedullary plasmacytoma | Identical plasmablastic morphology and plasma-cell markers | Serum/urine M-protein, CD56 positivity, and multifocal intraosseous lytic lesions favor myeloma; EBER and HIV favor PBL[1][5][17][18] |
| DLBCL, NOS | Aggressive CD20+ large B-cell jaw lymphoma with overlapping destructive radiology | Strong CD20/PAX5 with retained B-cell program argues against PBL[9][14][19] |
| Burkitt lymphoma | High-grade jaw lymphoma with floating-tooth pattern, especially in younger patients | CD20+, CD10+/BCL6+ germinal-center phenotype and classic starry-sky without plasma-cell markers distinguish it[14][20][21] |
The highest-risk pitfall is treating a destructive gingival or periapical lesion as odontogenic infection; a mass that enlarges over weeks, fails conventional dental therapy, or recurs at an extraction site demands incisional or core biopsy with EBER and a plasma-cell/B-cell immunopanel, concurrent HIV testing, and—when plasma-cell neoplasm is possible—serum/urine protein studies.[1][13]
Histopathology
Microscopically, PBL is a diffuse, cohesive proliferation of large cells spanning immunoblastic to plasmablastic morphology, with round-to-eccentric nuclei, prominent central nucleoli, abundant basophilic cytoplasm, and frequent perinuclear hof in plasmacytic variants.[5][19] A starry-sky pattern from tingible-body macrophages, brisk mitotic activity, apoptotic bodies, and necrosis are common.[6]
The immunophenotype is plasma-cell type: positive CD138, CD38, IRF4/MUM1, and BLIMP1, with variable CD79a, EMA, and CD45, and negative CD20 and PAX5 (occasional weak/focal CD20).[1][7] Ki-67 is very high, commonly 80% or more.[22] Aberrant T-cell markers (CD2, CD3, CD4) and CD30 may appear; CD10/BCL6 are usually negative/weak, consistent with a non-germinal-center, post-germinal-center origin.[1][7]
By WHO 5th-edition criteria the essential features are plasmablastic/immunoblastic morphology, expression of plasma-cell antigens, and negativity for CD20, PAX5, ALK, and HHV8; EBER positivity, MYC rearrangement, and clonal IG rearrangement are desirable but not required.[19] EBER is detectable in roughly two-thirds of cases, and MYC translocation—often to an immunoglobulin partner—in about half.[5][7][22] Radiologic–pathologic correlation is key: the soft-tissue-dominant, cortically destructive imaging corresponds to a mucosa-based tumor invading bone, and EBER plus HIV status are the principal features separating PBL from morphologically identical plasmablastic myeloma.[1][14]
Management and prognosis
Diagnosis requires adequate tissue—incisional, excisional, or core biopsy is preferred over fine-needle aspiration given the unusual morphology and absent CD20.[1] Workup includes HIV testing, EBER, full immunophenotyping, serum/urine protein studies when myeloma is in question, metabolic and cross-sectional staging, bone marrow evaluation, LDH, and International Prognostic Index (IPI) assessment.[1][7]
- Chemotherapy: Standard CHOP is considered inadequate; guidelines and expert reviews favor more intensive, infusional regimens. Current expert recommendations use EPOCH-based therapy, with or without bortezomib—approximately six cycles for advanced-stage disease, and four cycles followed by about 30 Gy consolidative radiotherapy for early-stage disease.[1][7][23][24]
- HIV/immunosuppression: Antiretroviral therapy should be started or optimized in HIV-positive patients; reduction of iatrogenic immunosuppression is appropriate, but antiretroviral therapy alone is not adequate treatment. Zidovudine, cobicistat, and ritonavir are generally avoided during chemotherapy.[1][23]
- Consolidation and relapse: Autologous stem-cell transplant may be considered in first complete remission for high-risk patients. Relapsed/refractory disease is treated with aggressive-lymphoma salvage regimens incorporating bortezomib, daratumumab, or lenalidomide, with brentuximab vedotin an option in CD30-positive cases, followed by transplant for chemosensitive disease.[1][7][23][25]
Prognosis remains poor, with reported 5-year overall survival roughly 30–40% and historically short median survival, although recent early-stage and intensified-regimen data suggest improvement.[3][26] Adverse prognostic factors include advanced stage, high IPI, poor performance status, bone marrow involvement, and EBV-negative disease; HIV-negative status and MYC rearrangement also mark higher-risk disease.[23][26]
Special considerations
HIV testing is mandatory
Oral PBL is frequently the sentinel presentation of undiagnosed or uncontrolled HIV, so any newly diagnosed case warrants HIV serology regardless of known risk factors; identification of infection directly changes staging, prognosis, and concurrent antiretroviral management.[4][27] Testing should not be deferred because a patient appears immunocompetent; undiagnosed HIV is common in PBL, and HIV status changes treatment and prognosis.[1][8]
Pediatric occurrence
PBL is rare in children and, when it occurs, is usually EBV-associated and frequently arises in HIV-infected individuals; the entity should be considered in a child with a destructive, rapidly enlarging jaw or gingival mass.[3]