Lloyd et al. Diagnostic Pathology 2015, 10:
http://www.diagnosticpathology.org/content/10/1/

CASE REPORT

Open Access

An unusual and challenging case of
HIV-associated primary CNS Lymphoma with
Hodgkin-like morphology and HIV encephalitis
Isaac E. Lloyd1*, Parker W. Clement1, Karen L. Salzman2, Randy L. Jensen3, Mohamed E. Salama4
and Cheryl A. Palmer5

Abstract
HIV-associated primary CNS lymphomas are well-recognized, almost exclusively EBV-driven neoplasms with poor
clinical prognosis. We report a challenging, atypical case of an HIV-associated lymphoproliferative disorder with
unusual morphologic features reminiscent of Hodgkin Lymphoma, accompanied by HIV encephalitis. A 52-year-old
male presented with acute seizures after seven months of progressive neurocognitive decline that was clinically
diagnosed as progressive supranuclear palsy. Clinical work-up revealed HIV infection along with two ring-enhancing
lesions in the brain on MRI, and negative CSF EBV testing. Subsequent biopsy showed well-demarcated
hypercellular regions in the brain comprised of scattered Reed-Sternberg-like cells in a background of small to
medium-sized lymphocytes exhibiting focal angiocentricity and geographic necrosis. The atypical cells were positive
for CD20, EBV, and CD79a, and negative for CD45, GFAP, CD15, CD30, and p24. These cells were admixed with
numerous CD68-positive cells. The adjacent brain showed classic features of HIV encephalitis with perivascular,
CD68 and p24-positive multinucleated giant cells. This case illustrates several diagnostic pitfalls in the work-up of
HIV-associated brain lesions, as well as reporting a unique histomorphology for an HIV-related primary CNS
lymphoproliferative disorder.
Keywords: Primary Central Nervous System Lymphoma (PCNSL), Human Immunodeficiency Virus (HIV), Encephalitis

Background
Primary CNS lymphoma (PCNSL) is fairly common in
HIV-infected patients, affecting as many as 10 % of
Acquired Immunodeficiency Syndrome (AIDS) patients
in some autopsy studies [1]. It often presents late in the
disease process in the setting of severe immunosuppression, and is almost always associated with coincident
Epstein-Barr virus (EBV) infection [2, 3]. PCNSL typically
presents as a deep, intracranial mass lesion, sometimes
ring-enhancing on imaging, and is often difficult to
differentiate from toxoplasmosis radiologically. Histologic diagnosis is traditionally sought only in patients
who demonstrate lesional progression following a trial
of anti-toxoplasmosis therapy [2]. In recent years,
EBV DNA testing in CSF has also been promoted as
* Correspondence: isaac.lloyd@hsc.utah.edu
1
Department of Pathology, University of Utah, 15 North Medical Drive East,
Suite #1100, Salt Lake City, UT 84112, USA
Full list of author information is available at the end of the article

a useful tool for the diagnosis of PCNSL [4]. Histologically, the diagnosis is based on identification of infiltrating,
dyscohesive, atypical lymphocytes, often arranged in
angiocentric aggregates, and possibly exhibiting areas of
necrosis. If associated with HIV infection, multinucleated
giant cells, largely in perivascular locations, may be seen
throughout the brain and are diagnostic of HIV encephalitis. Immunophenotyping of the atypical cells by immunohistochemistry or flow cytometry is crucial for appropriate
diagnosis and classification. Final pathologic classification
of these tumors follows the World Health Organization
classification scheme for hematopoietic neoplasms [5], the
majority being classified as AIDS-related diffuse large
B-cell lymphomas (DLBCL) [6, 7]. We present the
following unique case of an HIV-associated PCNSL
with striking Hodgkin lymphoma-like morphology,
along with its diagnostic challenges.

© 2015 Lloyd et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
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Lloyd et al. Diagnostic Pathology 2015, 10:
http://www.diagnosticpathology.org/content/10/1/

Case presentation
A 52-year-old male with no significant past medical history was admitted for seizures after 7 months of cognitive and functional decline, 50-kilogram weight loss,
episodic seizures, paranoia, and delusions. A contrast
MRI revealed two ring-enhancing lesions in his brain, in
the left frontal lobe and right thalamus (Fig. 1).
The patient underwent an extensive clinical work-up
including an unremarkable lumbar puncture and negative testing for cryptococcus antigen, EBV (MGB Alert
EBV Probe, MGB Alert Primers, Elitetech/Epoch Biosciences, Princeton, NJ, USA; Limit of Detection in CSF:
500 copies/mL), cytomegalovirus (CMV), herpes simplex
virus (HSV), varicella zoster virus (VZV), toxoplasmosis,
cysticercosis, oligoclonal bands and myelin basic protein,
bacterial and fungal cultures, and flow cytometry for
lymphoma. However, he tested positive for HIV by
quantitative PCR (COBAS Ampliprep/COBAS TaqMan
HIV-1 Test v2.0, Roche Diagnostics, Indianapolis, IN,
USA) and combination antigen/antibody assay with confirmatory western blot (GS HIV Combo Ag/Ab EIA, GS
HIV-1 Western Blot, Bio-Rad Clinical Diagnostics,
Hercules, CA, USA), and had a CD4 T-cell count of 22
cells/μL. CT scan of the chest showed diffuse nodular
opacities, and a bronchoalveolar lavage was positive for
Pneumocystis jiroveci. No other significant abnormalities
were seen on whole-body imaging. The patient was diagnosed with Acquired Immunodeficiency Syndrome
(AIDS) and empirically treated for toxoplasmosis infection
of the brain. Repeat MRI of the brain a week later revealed
no improvement in the brain lesions, and stereotacticguided biopsy was performed of the left frontal lesion.
The biopsy was sent for intraoperative consultation via
frozen section, and showed mostly mildly astrogliotic

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brain parenchyma with a small focus of hypercellularity.
This focus was comprised of a mixture of small and
large epithelioid cells with nuclear pleomorphism, suspicious for a neoplastic process. There was no evidence of
acute inflammation or microorganisms such as toxoplasmosis. A portion of the specimen was submitted for flow
cytometric evaluation and was found to have no evidence of monoclonality or non-Hodgkin lymphoma, but
may not have contained lesional tissue.
Permanent microscopic sections were then reviewed
(Fig. 2), and showed fragments of brain parenchyma
with a diffuse mild astrogliosis and scattered multinucleated giant cells, mostly in a perivascular distribution,
consistent with HIV encephalitis. In addition, there was
a well-demarcated region of hypercellularity composed
of polymorphic cells, corresponding to the area noted at
frozen section diagnosis. This area contained small, mature lymphocytes, medium-sized cells with irregular nuclei
and abundant cytoplasm, and very large cells with hyperchromatic, bizarre nuclei, one or more eosinophilic nucleoli, and abundant eosinophilic cytoplasm, reminiscent of
Reed-Sternberg or Hodgkin cells. This polymorphic
population of cells was arranged in a diffuse sheet in
one area, but was also perivascular in other areas,
and formed a rim around a small area of necrosis.
Again, acute inflammation and microorganisms were
absent. Differential diagnostic considerations included
multifocal glioblastoma, lymphoma, and HIV or other
viral-related reactive changes.
Immunohistochemistry was initially performed for
glial fibrillary acidic protein (GFAP), MIB-1, CD45,
CD68, CMV, and toxoplasmosis antigen (Fig. 3). GFAP
was positive in reactive astrocytes within the background
brain, but negative in the atypical cells. CD45 highlighted

Fig. 1 Magnetic Resonance Images. Axial T1 post-contrast Magnetic Resonance Images (MRI) of the patient’s ring-enhancing lesions in the right
thalamus (a) and left frontal lobe (b) with central low signal suggesting necrosis. Axial FLAIR image at the level of the thalamic lesion (c) shows
edema surrounding the lesion in the right thalamus and left frontal lobe as hyperintense signal. There is mild diffuse cerebral volume loss which
is a common finding in HIV encephalitis

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Fig. 2 H&E Stained Sections. Photomicrographs of H&E stained sections showing fragments of brain tissue with distinct areas of gliosis,
hypercellularity, and necrosis (N) at 40X magnification (Part a). The gliotic brain exhibited perivascular multinucleated giant cells (arrows) (b, 200X,
and inset, 400X), while the hypercellular areas were comprised of polymorphous atypical cells with occasional angiocentric architecture (c, 200X)
and large, Reed-Sternberg-like cells (d, 400X)

only scattered small cells in the hypercellular areas. CD68
was diffusely positive in many of the medium-to-large epithelioid cells in the hypercellular areas, as well as in the
giant cells in the background brain parenchyma. MIB-1
was positive in approximately 50 % of the atypical cells,
while stains for CMV and toxoplasmosis were negative.
Gram, Grocott’s Methenamine Silver (GMS), acid fast
bacilli (AFB), and Fite special stains were also negative.
These findings, in particular the CD68 positivity and pathognomonic multinucleated giant cells in the background,
pointed away from a neoplastic glial or lymphomatous
process and toward a reactive histiocytic phenomenon associated with HIV infection.
However, in an effort to rule out rare CD45-negative
lymphomas, and due to the striking Reed-Sternberg-like
morphology, additional stains for CD15, CD30, CD20,
CD79a, and PAX5 were performed. EBV testing via in
situ hybridization (ISH), and a p24 immunostain were
also obtained. The large, Reed-Sternberg-like atypical

cells, along with most of the medium-to-large cells, were
strongly positive for CD20, CD79a, and EBV, and negative for CD15 and CD30 (Fig. 4). The majority of these
cells were also positive for MUM1, focally and weakly
positive for PAX5 and BCL6, and negative for CD10. Bcell clonality testing (Polymerase Chain Reaction-based
IGH + IGK B-Cell Clonality Assay™, Invivoscribe Technologies Inc, San Diego, CA, USA) yielded a clonal result.
P24 was positive in scattered clusters of multinucleated
giant cells in the background brain, but negative in the
CD20-positive cell population (Fig. 5). In light of this
staining pattern, the diagnosis of HIV-associated lymphoproliferative disorder was rendered alongside a diagnosis
of HIV encephalitis. The neoplasm was subclassified as a
Diffuse Large B-Cell Lymphoma (DLBCL) of postgerminal center origin (MUM1-positive).
Several days after the biopsy, the patient was started
on combination anti-retroviral therapy (cART), but developed additional complications. After discussion with

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A

B

C

D

Fig. 3 GFAP, MIB-1, CD68, and CD45 Immunohistochemistry. Photomicrographs of immunohistochemical stains show a reactive pattern for glial
acidic fibrillary protein (GFAP) in the background brain, but no significant staining in the hypercellular lesion (a,40X). The hypercellular region
exhibits significantly increased MIB-1 staining (b,100X), strong CD68 positivity (c,100X), and only rare, small, CD45-positive cells (D,400X) compared
to the background brain

the family, the patient was transitioned to palliative care
and died 3 weeks following the biopsy. An autopsy was
not performed.

Discussion
This case presented several unique and interesting diagnostic challenges, starting with the initial laboratory testing and flow cytometry results. The clinical presentation
and brain imaging allowed for a focused differential
diagnosis including common HIV-associated infectious
and neoplastic disorders. However, one of the first barriers to diagnosis was the lack of EBV-DNA detected in
the patient’s CSF. The sensitivity (80-100 %) and specificity (93-100 %) of EBV-DNA testing by PCR in the CSF
have traditionally been considered quite high for
PCNSL, making it a very useful diagnostic marker [6].
Though a recent study showed a more realistic sensitivity of 70 % and a specificity of 85 % [4], the negative

result in this case is still a less common result and one
that argued against a diagnosis of PCNSL. Similarly, flow
cytometric analysis, performed on a fragment of the
brain biopsy, was uninformative, most likely due to sampling error or neoplastic cell size.
One of the most challenging aspects of this case was
determining whether the pathologic process was truly
neoplastic or within the spectrum of reactive HIV- or
EBV-related changes. In our case, the majority of the
lesional cells were initially found to be strongly positive
for CD68 and negative for CD45. This immunophenotype is most consistent with a histiocytic infiltrate, and
in the setting of pathognomonic HIV encephalitis with
CD68-positive multinucleated histiocytes, would favor a
reactive process due to HIV infection. The most significant diagnostic pitfall would have been to then exclude a
lymphoproliferative disorder on the basis of a CD45negativity.

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Fig. 4 CD20, CD15, and CD30 Immunohistochemistry and EBV In Situ Hybridization. Photomicrographs of the hypercellular lesion show that the
large, Reed-Sternberg-like cells and many intermediate-sized cells were strongly positive for CD20 by immunohistochemistry (a,100X, and
inset,400X), and EBV via ISH (b, 400X); the large cells were negative for CD15 (c, 400X) and CD30 (d, 400X) by immunohistochemistry

Fig. 5 P24 Immunohistochemistry. Photomicrographs of the background brain show positive p24 immunohistochemical staining within the
multinucleated giant cells of HIV encephalitis (a, 400X), while the neoplastic cells are negative (b, 400X)

Lloyd et al. Diagnostic Pathology 2015, 10:
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Though commonly employed as a first-line hematolymphoid lineage-specific immunostain, the subset of
lymphoproliferative disorders lacking CD45 expression
is well-established. Immunostaining for CD45 is typically
negative in Reed-Sternberg cells in classic Hodgkin
lymphoma, the majority of plasmacytic neoplasms,
approximately 10 % of precursor B-cell neoplasms, some
anaplastic large cell lymphomas, and rarely other nonHodgkin lymphomas including DLBCL [8, 9]. The key to
the correct diagnosis in this case was the morphologic
recognition of large, atypical Reed-Sternberg-like cells.
Though difficult to miss, these cells also possessed
features of viral cytopathic effect, again leading to
consideration of a purely reactive phenomenon. However,
their overall cytologic atypia led to a thorough immunohistochemical work-up, identifying EBV-infected CD20positive B-cells, consistent with an HIV-associated B-cell
lymphoproliferative disorder.
Subclassification of this neoplasm presented a final,
interesting challenge in this case. PCNSLs are histologically defined using the World Health Organization
(WHO) Classification of Tumours of Haematopoietic and
Lymphoid Tissue [5], which separates AIDS-related
lymphomas into three general categories: 1) lymphomas
also occurring in immunocompetent patients, 2) lymphomas occurring more specifically in HIV-positive patients,
and 3) lymphomas also occurring in other immunodeficiency states. The most common subtype of AIDS-related
PCNSL is reportedly diffuse large B-cell lymphoma with
immunoblastic or plasmacytic differentiation, but Burkitt
and Burkitt-like subtypes as well as polymorphous unclassifiable neoplasms have also been reported [6, 7]. Interestingly, another pathologic entity termed the Atypical
Lymphoid Proliferation, not currently described by the
WHO, has been used to describe polyclonal proliferations
of pleomorphic, CD20, EBV-positive lymphocytes in cardiac myxomas [10]. These cases share striking morphologic similarities with our case as well as EBV positivity,
and may represent a pre-clonal entity sharing a similar
pathogenetic mechanism tied to EBV and a chronic inflammatory state.
Our case exhibited several features of Hodgkin lymphoma including striking Reed-Sternberg-like morphology,
a CD45-negative immunophenotype, EBV positivity, and
a background of small, mature lymphocytes and numerous
histiocytes. Though being a well-documented subtype of
AIDS-related systemic lymphoma, Hodgkin lymphoma has
not been reported as a subtype of AIDS-related PCNSL.
Our case also exhibited strong CD20 expression in both
the large and intermediate-sized cells, and lacked CD15
and CD30 expression characteristic of Hodgkin lymphoma.
While morphologically consistent with Hodgkin lymphoma, the immunophenotype in this case led to its final
classification as diffuse large B-cell lymphoma.

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Regardless of the immunophenotypic classification, the
prognosis of patients with AIDS-related PCNSL is unfortunately dismal, with a median survival of 1 to
2.5 months with supportive care alone [6]. Whole-brain
radiation is the most common treatment employed, and
has been reported to increase median survival from 2 to
5.5 months [11]. Patients have also been treated with
antiretroviral therapy (HAART) without significantly
prolonged survival [6]. Chemotherapy is typically contraindicated due to the severe risk of infection in these immunocompromised patients. Our patient, unfortunately,
also experienced a characteristically poor outcome.

Conclusions
We have reported a challenging case of an HIV-associated
lymphoproliferative disorder with unusual morphologic
features reminiscent of Hodgkin Lymphoma. This case
highlights several common and important diagnostic pitfalls that can occur in the work-up of patients with HIV
and brain abnormalities on imaging. Early diagnostic pitfalls included negative CSF EBV testing, likely due to the
insensitivity of this test, and negative flow cytometric analysis, which can easily result from sampling error. Upon
biopsy, the pathologic diagnosis was complicated by a
CD45-negative immunophenotype and Hodgkin-like
morphology. In fact, this is the first known report of this
unique morphology in the setting of an HIV-related primary CNS lymphoproliferative disorder, and is of unknown clinical significance. We hope that improved
understanding of the pathology of these neoplasms may
lead to timely, appropriate, and perhaps earlier, diagnosis
and improved treatment options.
Consent
Written informed consent was obtained from the patient’s next of kin and power of attorney for publication
of this Case Report and any accompanying images. A
copy of the written consent is available for review by the
Editor-in-Chief of this journal.
Abbreviations
PCNSL: Primary CNS Lymphoma; HIV: Human Immunodeficiency Virus;
AIDS: Acquired Immunodeficiency Syndrome; DLBCL: Diffuse Large B-Cell
Lymphoma; WHO: World Health Organization; EBV: Ebstein-Barr Virus;
CMV: Cytomegalovirus; HSV: Herpes Simplex Virus; VZV: Varicella Zoster Virus;
HAART: Highly Active Anti-Retroviral Therapy; cART: Combination AntiRetroviral Therapy; GMS: Grocott’s Methenamine Silver; AFB: Acid Fast Bacilli;
CSF: Cerebrospinal Fluid.
Competing interests
The author(s) declare that they have no competing interests.
Authors’ contributions
IEL – participated in the neuropathologic analysis and drafted the
manuscript. PWC – participated in the hematopathologic analysis, prepared
images, and helped draft the manuscript. KLS – participated in the radiologic
analysis, prepared radiologic images, and edited the manuscript. RLJ –
participated in the neurosurgical and clinical management and edited the
manuscript. MES – participated in the hematopathologic analysis and

Lloyd et al. Diagnostic Pathology 2015, 10:
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Page 7 of 7

conceived of the hematopathology implications of this report. CAP –
participated in the neuropathologic analysis, designed the report, and edited
the manuscript. All authors read and approved the final manuscript.
Author details
1
Department of Pathology, University of Utah, 15 North Medical Drive East,
Suite #1100, Salt Lake City, UT 84112, USA. 2Department of Radiology,
University of Utah, 30 N 1900 E, Salt Lake City, UT 84132, USA. 3Department
of Neurosurgery, University of Utah, 175 N. Medical Drive East, Salt Lake City,
UT 84132, USA. 4Department of Pathology, University of Utah and ARUP
Laboratories, ARUP Laboratories, 500 Chipeta Way, Salt Lake City, UT
84108-1221, USA. 5Department of Pathology, University of Utah, Huntsman
Cancer Institute, 1950 Circle of Hope Drive, N3150, Salt Lake City, UT 84112,
USA.
Received: 7 July 2015 Accepted: 25 August 2015

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doi:10.1186/s13000-015-0387-9
Cite this article as: Lloyd et al.: An unusual and challenging case of
HIV-associated primary CNS Lymphoma with Hodgkin-like morphology
and HIV encephalitis. Diagnostic Pathology 2015 10:.

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