A Challenging Diagnosis of HHV-8-Associated Diffuse Large B-Cell Lymphoma, Not Otherwise Specified, in a Young Man with Newly-Diagnosed HIV

Introduction

Human herpesvirus 8 (HHV-8), also known as Kaposi sarcoma herpesvirus, is a DNA oncovirus and class I human carcinogen [1]. During the human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) epidemic, Kaposi sarcoma was identified as an aggressive malignancy associated with an immunosuppression and infection with HHV-8 [2,3]. Further research has demonstrated the association between HHV-8 and several other lymphoproliferative disorders (LPDs). According to the World Health Organization’s Classification of Tumors of Haematopoietic and Lymphoid Tissues, these LPDs include plasmablastic lymphoma, primary effusion lymphoma (PEL), HHV-8-positive multicentric Castleman disease (MCD), HHV-8-positive germinotropic lymphoproliferative disorder (GLPD), and HHV-8-associated diffuse large B-cell lymphoma, not otherwise specified (DLBCL, NOS) [4].

DLBCL, NOS is a rare and aggressive subtype of lymphoma observed in approximately 0.1% of the population, which is primarily diagnosed in patients with HIV or other significant immunodeficiencies [5,6]. HHV-8-associated diffuse large B-cell lymphoma, not otherwise specified (HDN) usually evolves from HHV8-associated multicentric Castleman disease (MCD), which is a distinct disease characterized by widespread inflammation, lymphadenopathy, and overproduction of IL-6. Reports have established that up to 25% of MCD patients develop a concurrent lymphoma [5,7]. DLBCL, NOS typically presents as a rapidly enlarging mass associated with B symptoms such as fevers, night sweats, and weight loss, with 71% of cases presenting with extranodal involvement [8].

Due to similar clinical presentations, it can be difficult to distinguish DLCBL, NOS from other germ inotropic LPDs. Pathology must be obtained to determine genetic profile, histologic findings, and immunophenotype [9]. Additionally, organ involvement, association with HIV or Epstein-Barr virus (EBV), and clinical presentations are critical in distinguishing one LPD from another [9]. We present a case of a newly-diagnosed HIV-positive man who presented with HHV-8-associated DLBCL, NOS with an unusual pattern of disease involvement. Concurrent development of renal failure, respiratory failure, transaminitis, and pancytopenia further complicated the clinical picture and our ability to reach a final diagnosis. We discuss the complexities in diagnosis due to the patient’s advanced HIV and multi-organ failure and the overlap in clinical syndromes.

Case Report

A 26-year-old man with past medical history of seizures initially presented immediately following a pre-syncopal episode at work. He also developed intermittent fevers 4 days prior to admission and microscopic hematuria. His history was notable for an approximately 9 kg weight loss over the month prior to admission, as well as approximately 1 week of intermittent dyspnea and non-productive cough. Labs on admission were remarkable for hyponatremia (134 mmol/L), hypokalemia (2.2 mmol/L), anemia (hemoglobin 6.8 g/dL), urea nitrogen 27 mg/dL, serum creatinine 2.45 mg/dL (baseline ∼1 mg/dL), and ferritin 4770 ng/mL (reference range 12–410 ng/mL). The physical exam was initially remarkable only for oral thrush, a non-tender distended abdomen, and ascites without appreciable organomegaly. A rapid human immunodeficiency virus (HIV) test was positive. He denied prior history of HIV but reported high-risk behavior. At presentation his CD4 count was 20 cells/μL and his HIV RNA quantitative load was 632 622 copies/mL. His clinical picture consisting of electrolyte derangements, isolated anemia, and acute kidney injury was attributed to uncontrolled HIV and acute retroviral syndrome. He initially responded well to blood transfusions and started highly active antiretroviral therapy (HAART) consisting of emtricitabine, tenofovir, and dolutegravir, which was held after 3 days due to progressive renal failure. After the initiation of renal replacement therapy, HAART was resumed after holding for 8 days.

His hospital course was complicated by persistent high fevers, altered mental status, hypoxic respiratory failure requiring high-flow oxygen supplementation, worsening renal function requiring hemodialysis, bilateral pleural effusions, hyperbilirubinemia, and pancytopenia. He also developed hypoalbuminemia (2.2 g/dL) and anasarca. To evaluate his sudden clinical deterioration, computed tomography (CT) imaging of the chest, abdomen, and pelvis without intravenous contrast was performed, which revealed a borderline retroperitoneal lymph node (measuring 1.6 cm by 1.3 cm) and splenomegaly up to 16.3 cm. His altered mentation was best described as intermittent lethargy, flat affect, and selective responsiveness to interview questions, without focal neurologic deficits. His encephalopathy was likely multifactorial and improved prior to discharge without any notable findings on brain imaging.

The patient’s clinical status continued to decline despite HAART, which prompted consideration of additional and differential diagnoses. Other remarkable diagnostic studies included a positive shigella toxin stool test, triglycerides 262 mg/dL (reference range 30-149 mg/dL), EBV IgG >8.0, EBV DNA 9320 copies/mL (reference range <300 copies/mL), and ADAMSTS13 32% (reference range 68–163%). He developed pancytopenia and coagulopathy with INR 1.40–1.74 and aPTT 34.0–60.1 seconds (reference range 23.0–33.0 s), complicated by bleeding from peripheral IV and central line sites and spontaneous ecchymosis.

The differential for his pancytopenia was broad. The anemia was thought to be multifactorial due to chronic disease and blood loss from ongoing hematuria. He developed severe thrombocytopenia within a week after admission, with his platelets dropping from 165 k/uL (reference range 150–399 K/uL) to 7 k/uL. The differential for thrombocytopenia included drug-induced (fluconazole, cefepime), myelosuppression from acute infection, uncontrolled HIV/AIDs, liver dysfunction, and HIV-induced immune thrombocytopenic purpura (ITP). His coagulopathy was attributed to liver dysfunction, although disseminated intravascular coagulation (DIC) remained on the differential despite an elevated fibrinogen (529 mg/dL), as fibrinogen is a known acute-phase reactant. The altered mentation, renal dysfunction, fever, thrombocytopenia, and positive Shiga stool test raised the possibility of atypical hemolytic uremic syndrome (HUS), although his laboratory studies were not entirely consistent with hemolysis (haptoglobin within normal limits at 313 mg/dL). Finally, hemophagocytic lymphohistiocytosis (HLH) was a consideration given his altered mental status, fever, bicytopenia, elevated triglycerides, splenomegaly, and elevated ferritin (peaking at 8000 ng/mL). The patient’s significant EBV viral load and acute HIV could have been potential triggers for the development of HLH.

Due to concern for Shiga-induced thrombotic microangiopathy or HIV-induced immune thrombocytopenic purpura, he was started on oral prednisone 1 mg/kg. Although labs were not entirely consistent with hemolysis, 3 sessions of empiric plasmapheresis (4500 mL exchanged each session) were trialed due to persistent thrombocytopenia. Given lack of improvement with steroids and plasmapheresis, a thoracentesis was performed, which resulted in exudative fluid per Light’s criteria [10]. Preliminary cytology was initially reported as benign, with later revision denoting atypical plasma cells with occasional multinucleated and giant forms, suspicious for an underlying lymphoproliferative neoplasm. Serum immunofixation studies did not reveal any evidence of monoclonality in IgH or light chains. Peripheral flow cytometry showed 6% of white blood cells were large, cytoplasmic lambda-restricted, CD19+, CD20 dim to negative, CD38+, CD138+ plasma cells. Meanwhile, the patient developed new scattered violaceous papules on his chest and an infectious disease evaluation showed human herpesvirus-8 (HHV-8) serum DNA positivity.

Subsequent bone marrow biopsy and aspiration revealed marked, reactive polytypic plasmacytosis staining for kappa and lambda in normal proportion, and hematopoiesis with secondary dysplastic changes. Malignant cells were not evident in the aspiration or on hematoxylin and eosin biopsy stains. Occasional scattered cells were HHV-8+, most with only slightly enlarged and irregular nuclei, suspicious for HHV-associated diffuse large B-cell lymphoma, not otherwise specified (HDN). Figure 1 illustrates the bone marrow findings. Given the persistently elevated bilirubin (peaking at 33.7 mg/dL) and blood and marrow findings, a transjugular liver biopsy was performed to evaluate for lymphomatous involvement of the liver. Sections of the liver biopsy showed marked acute cholestasis, with mainly portal but some sinusoidal clusters of large cells with associated necrotic hepatocytes and apoptotic debris. The large malignant cells were cytoplasmic lambda-positive, kappa-negative on light chain in situ hybridization assays; weakly positive for CD79a, and negative for CD20 and for PAX5. As in the marrow, these cells were positive for HHV8 on immunostaining, and negative for EBV (EBER in situ hybridization). Figure 2 demonstrates the liver biopsy findings. Subsequent analysis of ascites fluid showed similar malignant cells. The patient’s transaminitis was thought to due to multifactorial cholestasis secondary to HHV-8, angioendotheliomatosis, HIV, and medications including HAART. The patient was unable to complete full staging work-up consisting of MRI brain, spine, and lumbar puncture due to anxiety, so these procedures were deferred because they would require anesthesia and high-risk intubation. Figure 3 summarizes the patient’s clinical course, including serial platelet counts (Figure 3A), serum creatinine trend (Figure 3B), hemoglobin values (Figure 3C), WBC and ANC counts (Figure 3D), and trend of liver function tests (Figure 3E).

HHV-8-associated DLBCL, NOS does not have any disease-specific treatment modalities; therefore, patients tend to receive treatment primarily following the guidelines for that of DLBCL, NOS [11]. It is important to note that our patient could not complete staging due to anxiety and high risk for anesthesia, but was presumed to be Stage IV due to the bone marrow and liver involvement. Given presumed staging and medical comorbidities, our patient was started on a modified R-CHOP therapy, with piecemeal initiation of chemotherapy to minimize toxicity given multiorgan failure at diagnosis. He initially received dexamethasone 40 mg daily for 4 days, followed by Cytoxan (560 mg/ m2), then doxorubicin (12.5mg/m2). Dose-reduction of Cytoxan and doxorubicin, as well as holding vincristine, was indicated given severe hyperbilirubinemia and transaminitis. Rituximab was held given CD-4 count <50. His pancytopenia resolved after chemotherapy. Renal function improved drastically without further indications for renal replacement therapy and he was able to resume HAART (consisting of abacavir-dolutegravir-lamivu-dine 600-50-300 mg once daily), prior to discharge. With treatment of underlying HDN and a diuretic regimen, his pleural effusions improved and acute hypoxic respiratory failure resolved. Shigellosis complicated by hematochezia and protein-wasting enteropathy was treated with a 7-day course of ceftriaxone. The patient survived to discharge and continued to receive modified R-CHOP therapy with significant clinical improvement, but died 11 months later due to multiorgan failure in the setting of gastrointestinal bleeding and COVID-19 pneumonia.

Discussion

HDN is a rare form of lymphoma that occurs in the setting of AIDS, usually evolving from HHV8-associated multicentric Castleman disease. Here, we discuss the unique diagnostic challenges this patient posed in the setting of HIV infection and multiorgan dysfunction.

This patient’s presenting concern was pre-syncope, which independently introduces a broad differential diagnosis. The development of fevers, multiorgan failure (respiratory, renal, liver), electrolyte derangements, and pancytopenia made it difficult to reach a comprehensive diagnosis. Confounding processes including chronic blood loss from hematuria, liver dysfunction, myelosuppression secondary to critical illness, and medications (fluconazole, cefepime, ceftriaxone) confounded the etiology of pancytopenia, as discussed previously. However, given continued clinical decompensation, investigation of a systemic process was warranted.

One major differential diagnosis was hemophagocytic lymphohistiocytosis (HLH), characterized by cytokine activation leading to hyperinflammatory immune response [12]. The HLH-2004 criteria outline the 8 parameters for diagnosis, requiring 5 of the following criteria to be met for diagnosis: prolonged fever, hepatosplenomegaly, bicytopenia, hypertriglyceridemia or hypofibrinogenemia, hyperferritinemia, hemophagocytosis, low natural killer cell activity, and an elevated soluble IL-2 receptor [13]. HLH can occur secondary to autoimmune diseases, infections, or malignancy [14]. Viruses are one of the most common triggers, especially EBV [15]. Several studies have demonstrated evidence of EBV-associated HLH with the identification of HIV as an independent risk factor in HLH development [16,17]. Our patient technically met the diagnostic criteria for HLH because he had fever, pancytopenia, hypertriglyceridemia, hyperferritinemia, and elevated IL-2 receptor (21 010 pg/mL). Our patient’s positive EBV viral load and newly-diagnosed HIV/AIDS could have been HLH triggers. However, his bone marrow biopsy did not show evidence of hemophagocytosis, but rather HHV-8 involvement. Diagnosis of HLH is challenging, as symptoms are nonspecific and involve multiorgan dysfunction. Glucocorticoids are the mainstay of HLH therapy, with various immunosuppressive and cytotoxic treatments available depending on the underlying cause of acquired HLH [13].

Thrombotic microangiopathic processes, such as thrombotic thrombocytopenic purpura (TTP), atypical hemolytic uremic syndrome (HUS), or disseminated intravascular coagulation (DIC) were also considered as differential diagnoses. TTP classically manifests with microangiopathic hemolytic anemia and thrombocytopenia, associated with fever and end-organ damage, including renal failure or neurologic dysfunction [18]. TTP is caused by a deficiency of ADAMTS13, a matrix metalloproteinase that cleaves von Willebrand factor (vWF), leading to large vWF multimers causing shearing and microthromboses. TTP can occur idiopathically or secondary to medications or predisposing conditions, including autoimmune disease, malignancy, or infection [18]. Our patient met many criteria for TTP or atypical HUS given his encephalopathy, renal failure, anemia, thrombocytopenia, and fevers. His HIV infection could have provoked a thrombotic microangiopathy (TMA), as HIV has been demonstrated to increase the risk of acquired TTP, especially in the setting of untreated acute disease and low CD4 count [19]. Shiga-toxin-related HUS was also a consideration given our patient’s positive Shiga stool test and intermittent hematochezia. However, TTP, HUS, and DIC was excluded given lack of hemolysis, elevated haptoglobin, and hyperfibrinogenemia.

Given our patient’s refractory thrombocytopenia, there was concern for an immune-mediated process such as ITP, which can be idiopathic or secondary to malignancy, autoimmune disease, or infection [20]. Secondary ITP has been reported with HIV, among other infectious diseases, with a study reporting a 10.8% incidence of thrombocytopenia in patients with CD4 counts <200 cells/uL [21]. Given our patient’s HIV, it is possible that his thrombocytopenia was exacerbated by an immune complex-mediated ITP, antiplatelet glycoprotein antibodies, or cross-reactivity of antibodies and viral antigens [22]. Leukopenia and anemia are also frequently observed in HIV infection [23].

Our patient’s broad differential and the overlap observed among the various clinical syndromes posed a significant diagnostic challenge. His symptoms were initially attributed to acute HIV infection with failure to clinically improve after initiation of HAART. After an extensive diagnostic work-up, he was revealed to have atypical plasma cells demonstrating lambda light chain restriction within his blood, and scattered HHV8+ cells and reactive changes within his bone marrow. A critical step in arriving at an accurate diagnosis was liver failure, which could not be explained by the other proposed diagnoses and warranted liver biopsy, which demonstrated B lineage lymphoma, consistent with HHV-8-associated DLBCL, NOS.

Additional lymphoproliferative disorders that can present similarly to HHV-8-associated DLBCL, NOS include EBV+ DLCBL, NOS, plasmablastic lymphoma (PBL), and primary effusion lymphoma. Bone marrow biopsy would reveal negative EBV-encoded RNA (EBER), effectively ruling out EBV+ DLBCL, NOS [9].

Plasmablastic lymphoma (PBL) presents typically in the fifth decade of life with B symptoms and an oral cavity mass and is associated with HIV infection [9]. However, PBL would be expected to have negative CD10 and CD20 markers, which were observed to be positive in our patient. Additionally, 80% of PBL are associated with EBER, which was absent from our patient’s bone marrow [5]. PEL can present in younger, immunocompromised adults worldwide, with a preponderance for males, similar to HHV8+ DLBCL, NOS [9]. Both LPDs can have a plasmablastic morphology and strong association for HIV and HHV-8 infection. However, the splenic and nodal involvement, lambda light chain restriction, and lack of CD45 expression observed in our patient helped to distinguish HHV-8-associated DLBCL, NOS from PEL [9].

Given the rarity of HHV-8-associated DLBCL, NOS, there is minimal epidemiologic or clinical data on diagnosis, treatment, and management of these patients. Untreated HIV patients are especially at risk for opportunistic infections such as HHV-8 and its subsequent complications, including DLBCL, NOS. Our patient was critically ill with renal failure, hepatotoxicity, and cardiovascular compromise requiring vasopressor support at the time of diagnosis, which confounded his diagnosis and delayed the ability to obtain histopathologic confirmation of HHV-8 DLBCL, NOS. At present, the only definitive diagnosis involves involved lymph node or extranodal biopsy with immunohistochemistry with characteristic effacement of typical lymph nodal architecture replaced by sheets of HHV-8-positive and EBER-negative plasmablasts [24]. There are no specific guidelines on treatment for HHV-8-associated DLBCL, NOS beyond treating the underlying HIV with HAART and standard DLBCL-directed chemotherapy such as R-CHOP or EPOCH [11]. Chemotherapy regimens can be significantly limited in patients with significant multiorgan dysfunction, such as ours. Further investigations into awareness, diagnosis, and treatment for HHV-8-associated DLBCL, NOS is crucial to improve care in this population.

Conclusions

The management of HHV-8-associated DLBCL, NOS is complex, requiring a multifaceted approach to ensure appropriate diagnosis while minimizing infection risk and patient harm. A multidisciplinary approach is necessary for appropriate management given that HHV-8-associated DLBCL, NOS can be difficult to diagnose due to its overlap with other lymphoid malignancies that have a similar plasmablastic appearance on biopsy and immunohistochemical staining. HHV-8-associated DLBCL, NOS is a rare diagnosis, observed in approximately 0.1% of the population, which can be further complicated by difficulties in staging and lack of a standard-of-care treatment modality. This case emphasizes the difficulty in achieving an adequate diagnosis of HHV-8-associated DLBCL, NOS when a patient presents with multiorgan failure with a broad differential for their various vague signs and symptoms. The lack of standardized treatment for HHV-8-associated DLCBL, NOS, complicated by our patient’s renal and liver dysfunction, required a novel approach consisting of piecemeal and dose-reduced R-CHOP therapy. There are limited data and evidence-based medicine on this type of malignancy, and further investigations into the diagnosis and management HHV-8-associated DLBCL, NOS are warranted. Further reports on successful treatment outcomes of HHV-8-associated DLBCL, NOS, especially in medically complex patients with comorbidities and multiorgan failure, can help further develop this area of research and improve patient outcomes.