Lymphomas arising primarily in the female genital tract are rare, though secondary involvements are not uncommon.2 Transient lesions mimicking lymphomas are known under the name of “florid reactive lymphoid hyperplasia,” “pseudolymphoma,” or “lymphoma-like lesion.”1,3 In a case series by Geyer et al.,1 lymphoma-like lesions of the endometrium were always associated with chronic endometritis, and one of these three cases was associated with EBV reactivation. Though traditional reasoning suggests that lymphoma-like lesions are of polyclonal origin, some of them have been proved to be a monoclonal proliferation.1 This underscores the sometimes blurry distinction between benign inflammation and lymphomas.
Plasmablastic lymphoma is a mature B-cell neoplasm with plasmablastic differentiation, often associated with HIV infection and other forms of immunosuppression.4–6 A classic example is a tumor in the oral mucosa of an HIV-positive patient.7 EBV is positive in 60–75% of cases.4,8 In HIV-negative, non-transplant patients, Tchernonog et al9 included local inflammation, such as anal fistula and skin abscess, as a type of immune dysregulation predisposing to the disease, in addition to systemic inflammation, malignancy, and old age. Although it is usually an aggressive disease, spontaneous regression has been seen in a few cases: in HIV-positive patients on antiretroviral therapy,10,11 in patients with autoimmune disease after decreasing12 or stopping13 immunosuppressive therapy, and in an HIV-negative patient who had not undergone any intervention.14
Plasmablastic lymphoma in the uterus is very rarely reported. After excluding secondary involvement,15 we identified four reported cases of patients aged 47 years16, 54 years17, 61 years18, and 85 years, respectively.19 Only the 61-year-old patient was HIV-positive, while the others were HIV-negative. The 47-year-old patient died shortly after the diagnosis, while the 85-year-old patient responded well to chemoradiotherapy and was alive after 19 months. The patient outcomes of the other two cases were not reported.
In our case, the histomorphology and immunophenotype were most consistent with the diagnosis of plasmablastic lymphoma. Important differential diagnoses included ALK-positive large B-cell lymphoma, HHV8-positive diffuse large B-cell lymphoma, diffuse large B-cell lymphoma associated with chronic inflammation (DLBCL-CI), and florid reactive lymphoid hyperplasia (lymphoma-like lesion or pseudolymphoma). ALK and HHV8 negativity on immunohistochemistry was not consistent with the diagnosis of ALK-positive large B-cell lymphoma and HHV8-positive diffuse large B-cell lymphoma, respectively. DLBCL-CI is an interesting consideration, especially considering that many cases arise in inflamed closed spaces such as pyothorax and pseudocysts and a subset is of excellent prognosis. Moreover, a case of DLBCL-CI with plasmacytic differentiation was recently reported.20 On the other hand, anal fistula and skin abscess associated with plasmablastic lymphoma in the aforementioned case series9 might also be considered as closed spaces with chronic inflammation. These cases and ours might represent a conceptual overlap between plasmablastic lymphoma and DLBCL-CI. Depending on how the disease is defined, a case for the diagnosis of florid reactive lymphoid hyperplasia could also be made. The clinical course of lymphoma, which regresses spontaneously, and that of pseudolymphoma would be indistinguishable. Reanalysis of cases that were retrospectively diagnosed as florid reactive lymphoid hyperplasia might reveal some cases that could also be interpreted as spontaneously regressed lymphoma.
When atypical lymphoplasmacytic proliferation is encountered, the diagnosis and clinical decision making is often difficult. Hence, multidisciplinary discussion is crucial for the appropriate management of these patients.