HIV-Related Primary Diffuse Large B Cell Lymphoma of the Appendix. What Can We Learn?
Authors: Janania Martinez Michelle , Diaz Adolfo E , Forker Cynthia 
Published: October 2019

Abstract
BACKGROUND:
The introduction of antiretroviral therapies has decreased the incidence of HIV associated Non Hodgkin's Lymphoma (NHL), and the median CD4 count on diagnosis has increased; however, the overall aggressive nature of HIV associated NHL has not changed. The gastrointestinal tract is the most common location for extranodal lymphomas, but primary appendiceal lymphoma (PAL) is extremely rare and represents only 0.015% of all gastrointestinal lymphomas. There is limited data on management of these patients; therefore, herein we present a review of the available literature along with our own, and first reported case to our knowledge, of HIV associated Primary Diffuse large B-cell lymphoma (DLBCL) of the appendix .
METHODS:
We did a detailed literature review using the PubMed and MEDLINE database for published cases of primary appendiceal lymphoma from 1973 to 2018 and found only 125 cases of PAL. We decided to exclude the following histologies due to their significantly different prognosis and management: mucosa-associated lymphoid tissue, Hodgkin's lymphoma and extraosseous plasmacytomas. Demographics (age, gender), tumor histology and clinical characteristics (presentation and management) were assessed. All patients with appendiceal lymphoma were categorized using the 2016 WHO classification of mature lymphoid neoplasms. This was in response to a case encountered at our institute where a 38-year-old woman with controlled HIV presented with right iliac fossa pain and findings of appendicitis found to have DLBCL in the appendix.
RESULTS AND DISCUSSION
PAL primarily afflicts males, the mean age has been shown to be around 54 years (range: 40-62 years) and usually presents clinically as appendicitis. Out of the total 125 cases of PAL reviewed, the most common histological type was DLBCL (34.4%- 43 cases) followed by Burkitt's (27.2%-34 cases). None of them have been reported as HIV associated.
Our patient had the classic presentation of acute appendicitis (by clinical signs/symptoms and by imaging) and diagnosis was made post operatively. Our patient was 38 years old which is significantly younger than the expected range. The optimal treatment for intestinal lymphomas, let alone appendiceal lymphomas, has not been established yet. Most cases previously reported received appendectomy with adjuvant chemotherapy and had no disease recurrence at reported follow-up times. Our patient presented emergently with appendicitis and therefore underwent surgical resection prior to diagnosis of lymphoma, we then elected to proceed with adjuvant EPOCH-R based on efficacy data in the HIV population as per Sparano group. She had no evidence of disease elsewhere and has tolerated the chemo-immunotherapy selected with minimal hematologic toxicities, as expected.
CONCLUSION
We describe here a rare case of primary appendiceal lymphoma in a young patient with underlying HIV infection. Treatment of patients like ours is very challenging as there are no prior reported cases of HIV associated PAL and therefore no standard guidelines. There is limited data for PAL in general and further studies are required to determine natural course of disease and appropriate treatment protocols. After multidisciplinary discussion and review of limited literature decision was made to proceed with adjuvant EPOCH-R.

Disclosures
No relevant conflicts of interest to declare.