Monomorphic T-cell post-transplant lymphoproliferative disorder with features of HHV8-negative primary effusion lymphoma: an autopsy case and review of the literature.

A 67-year-old man underwent renal transplantation in his twenties. He developed refractory pleural effusion, with many large lymphocytes with severe atypia and mitosis in the effusion, indicating malignant lymphoma. He finally died of respiratory failure. An autopsy revealed atypical lymphocytes positive for CD3, CD4, and CD30 and negative for CD8, CD20, PAX5, human herpesvirus (HHV) 8, and Epstein-Barr virus-encoded small RNAs by immunohistochemistry and in situ hybridization. Atypical lymphocytes also had T-cell receptor gene rearrangements Jß2, Jγ2, and Jδ1 and chromosomal aberrations der(8)t(1;8)(q21;p21), add(13)(q12), add(14)(q32), and add(16)(q12-13). A few atypical lymphocytes were present at other sites. We finally diagnosed this case as monomorphic T-cell post-transplant lymphoproliferative disorder with features of HHV8-negative primary effusion lymphoma. A literature review only identified six cases (four HHV8-negative, two HHV8-positive) of effusion lymphoma of T-cell type, including the present case. Interestingly, about half of HHV8-negative and HHV8-positive cases had a history of renal transplantation in their twenties. All cases showed tumor CD30 expression, whereas CD4 and CD8 expressions were inconsistent. These findings indicated that this lymphoma may be associated with post-transplant lymphoproliferative disorder by renal transplantation at a young age, although further cases need to be analyzed.

[Hypomagnesemia induced by gastrointestinal losses due to carfilzomib].

A 67-year-old man with multiple myeloma had been treated with carfilzomib, lenalidomide, and dexamethasone (KRd) therapy. During the second course, he developed dyspnea, which gradually worsened. After admission, gastrointestinal losses of magnesium were confirmed, and intravenous magnesium was administered, which consequently improved his symptoms. Although KRd therapy was resumed, hypomagnesemia was recurring. Therefore, carfilzomib was replaced with ixazomib, which improved the patient's hypomagnesemia. The major causes of hypomagnesemia are gastrointestinal and renal losses; our case appeared to have gastrointestinal losses of magnesium and was successfully treated by discontinuing carfilzomib. Hypomagnesemia should be considered in patients receiving carfilzomib; furthermore, clinicians should consider discontinuing carfilzomib as its treatment.

Peripheral T-cell lymphoma, not otherwise specified accompanied by central nervous system involvement with features of lymphomatosis cerebri.

Lymphomatosis cerebri (LC) is a rare variant of primary central nervous system lymphoma, and it is characterized by diffuse cerebral infiltration of malignant lymphoma cells without evidence of a mass lesion. Herein, we report a patient with systemic peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) who had central nervous system involvement mimicking LC. A 72-year-old immunocompetent male presented with rapidly progressive dementia. Fluor-deoxy-glucose (FDG) -positron emission tomography revealed increased FDG uptake in the bone and skin. Histopathological examination of the skin lesion revealed PTCL-NOS infiltration. A FLAIR MRI scan of the brain revealed diffuse hyperintense lesions in the cerebral white matter of both hemispheres. These lesions were not enhanced with gadolinium, and there was no perceptible mass effect. We performed a brain biopsy, and the histology results were consistent with PTCL-NOS. The patient was treated with corticosteroid and chemotherapy; however the disease progressed, and he died 4 months after the diagnosis. This was a rare case of systemic lymphoma accompanied with central nervous system involvement mimicking LC.