ALBERT

Description: Introduction Primary cutaneous B-cell lymphomas (PCBCLs) arise within the skin without evidence of extracutaneous involvement at the time of diagnosis. The incidence of PCBCL is rare, and PCBCLs are less common than primary cutaneous T-cell lymphomas. There are three subgroups of PCBCL: primary cutaneous marginal zone lymphoma (PCMZL), primary cutaneous follicle-cell lymphoma (PCFCL), and primary cutaneous diffuse large B-cell lymphoma, leg type (PCDLBCL-LT). The 5-year survival rates of the former two subtypes exceed 90%, whereas PCDLBCL-LT is approximately 50% (Wilcox 2015). We describe a rare case of indolent PCMZL transforming into the more aggressive PCDLBCL-LT as well as a review of literature and case series. Case A 62-year-old man with history of PCMZL refractory to external beam radiation and rituximab chemotherapy presented with a two-month history of an enlarging rash and three nodules on his left leg. On physical exam, two violaceous, infiltrative plaques with distinct borders were present on the left leg, resembling his past PCMZL. Three new lesions were described as deep-seated 2 cm erythematous nodules (Fig 1). Histologic review of the new nodules revealed a diffuse, dermal-based atypical lymphoid infiltrate extending from the papillary dermis into the subcutis. The atypical lymphoid cells contained mostly round nuclei, vesicular chromatin, and prominent nucleoli consistent with an immunoblastic and centroblastic morphology (Fig 2). They expressed B-cell markers such as CD79a and CD19, and were negative for CD20 most likely due to prior treatment with rituximab. Immunohistochemistry demonstrated positivity for Bcl-2 and MUM1. Discussion Primary cutaneous diffuse large B-cell lymphoma, leg type (PCDLBCL-LT) is a rare and aggressive B-cell lymphoma. This subtype is positive for CD20 and CD79, negative for CD5 and CD10, and strongly positive for Bcl-2 and MUM1. It has the gene expression profile of the ABC subtype. A nodule on the lower leg is an ominous sign given this subtype's predilection for lower extremities. This subtype affects the elderly as opposed to the indolent subtypes that arise in middle age (Willemze 2005). Prognosticating PCDLBCL-LT is challenging, as survival rates vary from 40 to 70% (Willemze 2005). Additionally, the aggressive nature of PCDLBCL-LT confers use of more aggressive, systemic chemotherapy regimens. Rituximab, cyclophosphamide, hydroxydaunorubicin, vincristine, and prednisone (R-CHOP) chemotherapy followed by external beam irradiation is recommended, though no large prospective clinical trials have been performed to date. If lesions remain refractory to R-CHOP, the treatment goal should be redirected to treat as a refractory systemic diffuse large B-cell lymphoma which may require bone marrow transplant or targeted agents with known activity in the ABC subtype such as lenalidomide or ibrutinib. Transformation from PCMZL to PCDLBCL-LT is a rare event and has only been described in 2 case series (Table 1). In our review of the prior cases, the age group was heterogenous ranging from 29 years-old to 80 years-old. There was no consensus treatment, however, the majority of patients did receive at least CHOP-based regimen. Survival ranged from 24 months to 180 months, showing the heterogeneity of the disease process. In our patient, he underwent R-CHOP but progressed and then received salvage R-ICE with CR. He then underwent bone marrow transplantation but unfortunately had recurrence 36 days post-transplantation, proven PCDLBCL-LT, and he died 161 days following his allogeneic transplant. Conclusion Although PCMZL and PCFCL frequently recur despite treatment, transformation to PCDLBCL-LT is unusual. To date, transformation from PCMZL to PCDLBCL-LT has been described rarely in the literature (Table 1). PCMZL is indolent and is treated with external beam radiation therapy or surgical excision with excellent prognosis, the aggressive PCDLBCL-LT subtype has a poor outcome and requires systemic chemotherapy. Because of the vast difference in prognosis and treatment between PCMZL and PCDLBCL-LT, early recognition and exhaustive work-up is beneficial to the patient. Considering this transformation is both rare and diagnostically challenging, clinicians should have heightened concern for new nodular lesions in the setting of recurrent indolent primary cutaneous B-cell lymphomas. Disclosures Yazbeck: Celgene: Membership on an entity's Board of Directors or advisory committees; Gilead Sciences: Research Funding; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees.

Description: Introduction There are roughly 75,000 new cases of Non-Hodgkin's Lymphoma every year, representing almost 5% of all new cancer diagnoses. Indolent B-Cell Non-Hodgkin's Lymphoma (i-NHL) represents a heterogeneous group of lymphoproliferative malignancies, encompassing 40% of NHL, that remains largely incurable. Follicular lymphoma and marginal zone lymphoma (MZL) are the two most common subtypes of i-NHL. The B-cell receptor signaling pathway is activated in B-cell malignancy and mediates its activity mainly through the Phosphoinositide 3-kinase (PI3K) pathway. Furthermore, novel PI3K inhibitors, such as idelalisib and copanlisib, have shown impressive clinical activity in several indolent lymphomas including MZL. This further supports the important role of the PI3K pathway in these tumors. Therefore, we hypothesized that the PI3K-mTOR (mammalian target of rapamycin) pathway is sufficient for driving the pathogenesis of marginal zone lymphomas. Methods In order to test our hypothesis, we generated a genetically engineered mouse model carrying heterozygous knockout alleles of both the tumor suppressor genes Phosphatase and Tensin Homolog (PTEN) and Liver Kinase B1 (LKB1), leading to over-activation of the PI3K-mTOR pathway in all mouse tissues. We closely monitored these mice for tumor formation by at least weekly physical examinations for several months. Upon tumor detection, tumor size was recorded weekly using calipers, with an experimental endpoint of 15-20mm in any dimension. Upon reaching this endpoint, or if the surrounding area became necrotic/ulcerated, if the mouse's physical/behavioral condition deteriorated, or if there were any adverse conditions warranting mouse sacrifice, the mouse was euthanized and any existing tumors and any other tissues of interest were harvested. One half of the tumor was immediately preserved in a 4% paraformaldehyde solution and prepared for sectioning, H&E and immunohistochemical staining, with CD3 (T-cell marker), and PAX-5 (B-cell marker). The 2nd half of the tumor was processed using a "stomacher" machine to dissociate the tumor cells, which were then counted and frozen in accordance with cryopreservation guidelines suggested by the American Type Culture Collection (ATCC). Results We generated an initial cohort of 49 Pten+/-/Lkb1+/- mice. Among all mice, the average survival time was 6 months. Thirty mice died or were sacrificed due to disease progression, defined as either lymph node enlargement and/or splenomegaly. All mice showed either lymphadenopathy or splenomegaly (Figure 1). By Kaplan-Meier analysis, we see a steady decrease in both tumor-free and overall survival after 3 months of age. Utilizing the product limit method, the median survival time was 6 months (95% CI: 6, 8). A total of 51 lymph nodes were sent for IHC and pathological identification. Of the 51 nodes, 61.5% (N=32) showed indolent Non-Hodgkin's Lymphoma, 25% (N=13) were atypical, and 11.5% (N=6) were reactive. All lymph nodes with indolent NHL were Marginal Zone subtype (Figure 2), except one case that was suspicious for follicular lymphoma. We have not identified any large cell lymphoma or development of other malignancies. Discussion Marginal zone lymphoma remains an incurable indolent lymphoma that lacks preclinical models. As novel agents become available, it is important to have a better understanding of the underlying pathogenesis of this malignancy and be able to model it in a immunocompetent mouse with a preserved microenvironment. Our data provides, for the first time, a proof of concept on the role of the PI3K-mTOR pathway in the pathogenesis of marginal zone lymphoma and paves the way for future studies understanding the biology of this disease, and developing rational therapies for this incurable malignancy. Disclosures No relevant conflicts of interest to declare.

Description: Introduction A review of Uganda’s HIV Early Infant Diagnosis (EID) program in 2010 revealed poor retention outcomes for HIV-exposed infants (HEI) after testing. The review informed development of the ‘EID Systems Strengthening’ model: a set of integrated initiatives at health facilities to improve testing, retention, and clinical care of HIV-exposed and infected infants. The program model was piloted at several facilities and later scaled countrywide. This mixed-methods study evaluates the program’s impact and assesses its implementation. Methods We conducted a retrospective cohort study at 12 health facilities in Uganda, comprising all HEI tested by DNA PCR from June 2011 to May 2014 (n = 707). Cohort data were collected manually at the health facilities and analyzed. To assess impact, retention outcomes were statistically compared to the baseline study’s cohort outcomes. We conducted a cross-sectional qualitative assessment of program implementation through 1) structured clinic observation and 2) key informant interviews with health workers, district officials, NGO technical managers, and EID trainers (n = 51). Results The evaluation cohort comprised 707 HEI (67 HIV+). The baseline study cohort contained 1268 HEI (244 HIV+). Among infants testing HIV+, retention in care at an ART clinic increased from 23% (57/244) to 66% (44/67) (p 〈 .0001). Initiation of HIV+ infants on ART increased from 36% (27/75) to 92% (46/50) (p 〈 .0001). HEI receiving 1st PCR results increased from 57% (718/1268) to 73% (518/707) (p 〈 .0001). Among breastfeeding HEI with negative 1st PCR, 55% (192/352) received a confirmatory PCR test, a substantial increase from baseline period. Testing coverage improved significantly: HIV+ pregnant women who brought their infants for testing after birth increased from 18% (67/367) to 52% (175/334) (p 〈 .0001). HEI were tested younger: mean age at DBS test decreased from 6.96 to 4.21 months (p 〈 .0001). Clinical care for HEI was provided more consistently. Implementation fidelity was strong for most program components. The strongest contributory interventions were establishment of ‘EID Care Points’, integration of clinical care, longitudinal patient tracking, and regular health worker mentorship. Gaps included limited follow up of lost infants, inconsistent buy-in/ownership of health facility management, and challenges sustaining health worker motivation. Discussion Uganda’s ‘EID Systems Strengthening’ model has produced significant gains in testing and retention of HEI and HIV+ infants, yet the country still faces major challenges. The 3 core concepts of Uganda’s model are applicable to any country: establish a central service point for HEI, equip it to provide high-quality care and tracking, and develop systems to link HEI to the service point. Uganda’s experience has shown the importance of intensively targeting systemic bottlenecks to HEI retention at facility level, a necessary complement to deploying rapidly scalable technologies and other higher-level initiatives.

Description: Introduction: Indolent B-Cell Non-Hodgkin's Lymphomas (NHL) represent a heterogeneous group of lymphoproliferative malignancies, that remain largely incurable. Marginal zone lymphomas (MZL) are the second most common subtype of indolent NHL, and lack a unique cytogenetic identifying abnormality. The B-cell receptor signaling pathway is activated in B-cell malignancy and mediates its activity mainly through the Phosphoinositide 3-kinase (PI3K) pathway. Furthermore, novel PI3K inhibitors, such as copanlisib and parsaclisib, have shown impressive clinical activity in several indolent lymphomas including MZL. This further supports the important role of the PI3K pathway in the pathogenesis of this tumor. Therefore, we hypothesized that the PI3K-mTOR pathway is sufficient for driving the pathogenesis of MZL. Methods: In order to test our hypothesis, we generated a genetically engineered mouse model carrying heterozygous global knockout alleles of both the tumor suppressor genes Phosphatase and Tensin Homolog (PTEN) and Liver Kinase B1 (LKB1). This led to over-activation of the PI3K-mTOR pathway in all mouse tissues. We closely monitored these mice for tumor formation via weekly physical examinations for several months. Upon tumor detection, the mouse was sacrificed, and tumors were sectioned for histological characterization. In order to generate a more specific model of B cells, and more accurately mimic the underlying human disease, we used the Cre-LoxP system to create the CD19-Cre-PTENfl/fl-LKB1fl/fl. Results: Thirty mice of global KO PTEN+/- LKB1 +/- died or were sacrificed due to disease progression, defined as either lymph node enlargement and/or splenomegaly. All mice showed either abnormal lymphadenopathy or splenomegaly. By Kaplan-Meier analysis, we saw a steady decrease in both tumor-free and overall survival after 3 months of age. Utilizing the product limit method, the median survival time was 6 months (95% CI: 6, 8). A total of 51 lymph nodes were sent for immunohistochemistry and pathological characterization. Of the 51 nodes, 61.5% (N=32) showed indolent Non-Hodgkin's Lymphoma, 25% (N=13) were atypical, and 11.5% (N=6) were reactive. All lymph nodes with indolent NHL were of MZL subtype. Compared to wild type (n=3), the new CD19-Cre-PTENfl/fl -LKB1fl/fl (n=3) showed an overall increase in spleen mass (120 vs 196 mg, p=0.0564), % B1 cells (4% vs 59%, p= 0.0075), % MZ cells (5% vs 30%, p=0.0547), % plasma cells (1% vs 12%, p=0.0729), and decrease in % FO cells (80% vs 12%, p=0.0003) by flowcytometry. Further characterization of the new model is currently underway. Conclusion: Marginal zone lymphoma remains an incurable lymphoma that lacks reliable preclinical models. Our data provides, for the first time, a proof of concept on the role of the PI3K-mTOR pathway in the pathogenesis of marginal zone lymphoma and paves the way for future studies understanding the biology of this disease, and developing rational therapies for this incurable malignancy. Disclosures Yazbeck: Celgene: Consultancy; AstraZeneca: Consultancy; Gilead: Research Funding; Seattle Genetics: Consultancy; Verastem: Speakers Bureau.