DIAGNOSIS
The correct diagnosis is C, Plasmablastic lymphoma (PBL). An incisional
biopsy was undertaken and demonstrated extensive infiltration of the
lamina propria with sheets of neoplastic plamablasts.
Immunohistochemistry was positive for CD 138 and MUM 1 which are plasma
cell markers and negative for CD 20, a mature B cell marker (Figures 2a
and 2b). There was also marked positivity for Epstein-Barr virus-encoded
RNA in the sample (Figure 2c). These investigations confirmed the
diagnosis as Epstein Barr Virus-positive plasmablastic lymphoma,
consistent with viral-induced immunosuppression
Plasmblastic lymphoma is a rare but aggressive subtype of diffuse large
B-cell lymphoma (Non-Hodgkin lymphoma). It is estimated that PBL
comprises 2% of HIV-related lymphoma cases. It has a male predominance
(3:1), with a median age of diagnosis in HIV-positive patients of 42
years. It is strongly associated with immunodeficiency with 79 % of
cases having a concomitant HIV infection and 75% having an associated
EBV infection (Rodrigues-Fernandes et al., 2018). The Plasmablast is the
precursor of the plasma cell and it is proposed that EBV leads to the
prevention of apoptosis of these cells (Castillo et al., 2015).
The most notable feature of plasmablastic lymphoma is its predilection
for the oral cavity with 66% cases presenting here.
(Rodrigues-Fernandes et al., 2018) It most commonly presents as an
expanding mass lesion on the gingiva or palate. Patients can also
present with B symptoms: fevers, weight loss and night sweats in up to
40% of cases, however lymph node involvement is less frequently seen in
these patients. (Lopez and Abrisqueta, 2018). Currently available
chemotherapy fails to achieve good results and the prognosis of patients
with PBL is generally poor with a median overall survival of 5–15
months (Castillo et al., 2015).