Human Immunodeficiency Virus-associated primary effusion lymphoma: An exceedingly rare entity in cerebrospinal fluid

Primary Leptomeningeal Lymphoma: Clinicopathologic Features of 2 Rare Phenotypes

Primary leptomeningeal lymphoma is exceedingly rare. We describe 2 rare lymphoma cases with exclusive leptomeningeal disease: 1 ALK-positive (ALK+) anaplastic large cell lymphoma (ALCL) and 1 primary effusion lymphoma (PEL). Case 1: A 19-year-old man presented with symptoms concerning for leptomeningitis. Cerebrospinal fluid (CSF) analysis revealed lymphocytic pleocytosis. Spine MRI demonstrated pial enhancement from T10 through the conus medullaris and cauda equina enhancement/thickening. A biopsy showed leptomeningeal involvement by large lymphoma cells with hallmark cells and brisk mitotic activity. By immunohistochemistry, cells were CD7/CD30-positive with cytoplasmic ALK staining. No systemic disease was identified. The diagnosis of primary leptomeningeal ALK+ ALCL was made. Despite 2 CSF relapses requiring systemic therapy and autologous bone marrow transplant, the patient was in complete clinical remission 9 years after the diagnosis. Case 2: A 60-year-old, human immunodeficiency virus-positive man presented with symptoms suggestive of leptomeningitis. Brain MRIs revealed multifocal, supratentorial, and infratentorial leptomeningeal enhancement. A right frontal biopsy demonstrated leptomeningeal involvement by large lymphoma cells negative for B-cell immunostains, but CD138, MUM-1, and HHV8-positive, with aberrant CD3 expression. EBV-encoded RNA in situ hybridization was positive. In absence of solid lesions/extracranial involvement, the diagnosis of leptomeningeal PEL was rendered. Despite initial complete remission after chemotherapy, the patient died 9 months later.

Use of pembrolizumab with or without pomalidomide in HIV-associated non-Hodgkin's lymphoma

BACKGROUND

Non-Hodgkin's lymphoma (NHL) is currently the most common malignancy among people living with HIV (PLWH) in the USA. NHL in PLWH is more frequently associated with oncogenic viruses than NHL in immunocompetent individuals and is generally associated with increased PD-1 expression and T cell exhaustion. An effective immune-based second-line approach that is less immunosuppressive than chemotherapy may decrease infection risk, improve immune control of oncogenic viruses, and ultimately allow for better lymphoma control.

METHODS

We conducted a retrospective study of patients with HIV-associated lymphomas treated with pembrolizumab±pomalidomide in the HIV and AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute.

RESULTS

We identified 10 patients with stage IV relapsed and/or primary refractory HIV-associated NHL who were treated with pembrolizumab, an immune checkpoint inihibitor, with or without pomalidomide. Five patients had primary effusion lymphoma (PEL): one had germinal center B cell-like (GCB) diffuse large B cell lymphoma (DLBCL); two had non-GCB DLBCL; one had aggressive B cell lymphoma, not otherwise specified; and one had plasmablastic lymphoma. Six patients received pembrolizumab alone at 200 mg intravenously every 3 weeks, three received pembrolizumab 200 mg intravenously every 4 weeks plus pomalidomide 4 mg orally every day for days 1-21 of a 28-day cycle; and one sequentially received pembrolizumab alone and then pomalidomide alone. The response rate was 50% with particular benefit in gammaherpesvirus-associated tumors. The progression-free survival was 4.1 months (95% CI: 1.3 to 12.4) and overall survival was 14.7 months (95% CI: 2.96 to not reached). Three patients with PEL had leptomeningeal disease: one had a complete response and the other two had long-term disease control. There were four immune-related adverse events (irAEs), all CTCAEv5 grade 2-3; three of the four patients were able to continue receiving pembrolizumab. No irAEs occurred in patients receiving the combination of pembrolizumab and pomalidomide.

CONCLUSIONS

Treatment of HIV-associated NHL with pembrolizumab with or without pomalidomide elicited responses in several subtypes of HIV-associated NHL. This approach is worth further study in PLWH and NHL.

HHV8-related lymphoid proliferations: a broad spectrum of lesions from reactive lymphoid hyperplasia to overt lymphoma

Human herpesvirus 8 (HHV8)-associated lymphoid proliferations are uncommon and poorly characterized disorders mainly affecting immunosuppressed patients, especially with HIV infection. They encompass different diseases with overlapping features that complicate their classification. In addition, the role of HHV8 in reactive lymphoid hyperplasia is not well known. To analyze the clinicopathological spectrum of these lesions, we have reviewed 66 biopsies of 61 patients with HHV8 infection. All cases were also investigated for Epstein-Barr virus (EBV) and HIV infection. We identified 13 (20%) cases of HHV8-related reactive lymphoid hyperplasia, 2 (3%) HHV8 plasmablastic proliferations of the splenic red pulp, 28 (42%) multicentric Castleman disease, 6 (9%) germinotropic lymphoproliferative disorders, and 17 (26%) HHV8-related lymphomas. As expected, the pathologic subtype was predictive of overall survival (P<0.05). Forty-seven of our cases were HIV positive (77%). In addition to the classical presentation of the different entities, we identified novel and overlapping features. Reactive HHV8 proliferations were frequently associated with systemic symptoms but never progressed to overt HHV8-positive lymphoma. Two cases had a plasmablastic proliferation limited to spleen. Eight cases of multicentric Castleman disease had a previously unrecognized presentation shortly after the diagnosis of HIV infection, six cases had cavity effusions, and three showed plasmablast enriched proliferations. One germinotropic lymphoproliferative disorder was EBV negative and three occurred in HIV-positive patients, who had distinctive clinical and morphological features. Two of the HHV8-related lymphomas did not fulfill the criteria for previously recognized entities. All these findings expand the clinical and pathological spectrum of HHV8-related lymphoid proliferations, which is broader than current recognized.

Role of Imaging in Peritoneal Surface Malignancies

Imaging plays a vital role in the evaluation of peritoneal malignancies. The presence of peritoneal metastases (PM) alters tumor staging, with direct implications in treatment choice and prognosis. Cytoreductive surgery (CRS) and Hyperthermic intraperitoneal chemotherapy (HIPEC) as a combined modality treatment have led to prolonged survival and even cure in selected patients with PM. Better outcomes are seen in patients with limited disease spread. Therefore, early diagnosis of peritoneal tumor seeding is essential. Despite significant advancement of technology, assessment of the origin of PM is often difficult, due partly to the complex peritoneal anatomy and partly due to the complex overlap of imaging features. Multidetector CT (MDCT) is the main stay due to its wide availbility, rapid evaluation, robust technique and good resolution. Imaging plays a vital role in selecting patients for the combined modality treatment. MRI is not as popular as CT due to limited availability, time required for the study and lack of experience with interpreting the results. PET-CT is useful in ruling out extra peritoneal disease and it is the CT component that is more reliable for predicting the disease extent. This article reviews the current use of various imaging modalities in various stages of treatment of patients with PM especially those undergoing CRS and HIPEC.

Primary effusion lymphoma involving cerebrospinal fluid, deep cervical lymph nodes and adenoids. Report of a case supporting the lymphatic connection between brain and lymph nodes

We describe an unusual presentation of primary effusion lymphoma in CSF of a 45-year-old HIV-positive man, with no evidence of involvement of pleural, peritoneal or pericardial cavities. Cytologic examination and flow cytometric analysis suggested the diagnosis, eventually made in an excised deep cervical lymph node, in which the neoplastic cells involved selectively the sinuses. This case represents the fifth reported example of CSF involvement by this type of lymphoma, and supports the alleged connection between CSF and cervical lymph nodes via lymphatic vessels. Interestingly, review of an adenoidectomy specimen obtained 9 months before presentation for nonspecific complaints showed rare clusters of neoplastic cells involving surface epithelium and chorium, a finding that might represent a homing mechanism and implies an asymptomatic, occult phase of lymphoma development.