Blastic plasmacytoid dendritic cell (pDC) neoplasm (BPDCN) is a relatively rare hematological malignancy with significantly complex clinicopathological features that are still unclear. This study aimed to analyze the clinicopathological data of BPDCN and evaluate immunohistochemical detection of minimal bone marrow (BM) involvement. In this study, we examined skin and BM lesions from 6 patients with BPDCN. Neoplastic cells tested positive for CD303 (polyclonal, 100%; monoclonal, 40%) in the skin lesions and for CD303 (polyclonal, 100%; monoclonal, 67%) in the BM clots. Although immunostaining of CD4, CD56, CD123, CD303, and TCLl detected minimal BM involvement in 3 patients, morphological identification was challenging in the BM clots stained with hematoxylin–eosin. In conclusion, our results demonstrate the significance of observing BM smears to detect neoplastic cells and that immunohistochemical examination, including CD303 antibodies, is useful to detect minimal BM involvement. This study is the first to report the expression of thymic stromal lymphopoietin (TSLP) and its receptor in BPDCN cells. Therefore, the TSLP/TSLP receptor axis may be associated with the proliferation of BPDCN, and consequently, the survival of patients.

Recent studies have revealed the clinical and biological features of stage I follicular lymphoma (FL), but information about patients with stage I FL who underwent total resection after tissue biopsy is limited. Among 305 FL patients diagnosed between 2001 and 2013, clinical stage I disease was observed in 36 patients. Of these, 18 patients underwent total resection after diagnostic tissue biopsy. We used ¹⁸F-fluorodeoxyglucose positron emission CT for staging assessment in 13 of 18 patients (72.2%). The median age was 56.5 years. Six patients (33.3%) were male. The soluble interleukin-2 receptor alpha concentration was significantly lower than in patients with residual disease. Among these 18 patients, 7 patients (38.9%) were treated with a “watch-and-wait” (WW) policy, 7 (38.9%) were treated with involved-field irradiation, and 4 (22.2%) received systemic chemotherapy. Patients with resected disease were treated with significantly different strategies from those with residual disease (p = 0.0026). Five patients experienced relapse during follow-up (median follow-up: 48.2 months). All relapses were distant from the primary site, irrespective of treatment strategy. Among all stage I patients, disease resection was not a significant factor for survival (p = 0.9294). Collectively, the choice of treatment strategy was significantly influenced by patient status. Resection status was not significantly associated with survival after several treatment strategies.

Recent progress in anti-tumor therapy has revealed the significance of anti-tumor immune responses in tumor progression and clinical course in several kinds of malignant tumors. The draining lymph node is an important immune system component that contains a number of antigen-presenting cells, which induce rapid immune responses to foreign antigens. Current studies have shown that higher expression of CD169 on lymph node sinus macrophages is associated with the induction of anti-tumor immunity. In the present study, we searched for natural compounds that regulate the CD169-positive phenotype in macrophages to identify potential new anti-cancer agents targeting macrophage activation. Among 50 natural compounds, aculeatiside A, naringin, and onionin A significantly induced the CD169-positive phenotype in human monocyte-derived macrophages. These compounds also induced CD169 overexpression and secretion of inflammatory cytokines, including interleukin (IL)-1β and IL-12, in murine macrophages. Subcutaneous injection of aculeatiside A and naringin enhanced mRNA expression of IL-1β, IL12, and CD169 in regional lymph nodes in mice. These findings suggest aculeatiside A and naringin may enhance anti-tumor immune responses by inducing CD169-positive macrophages in lymph nodes.

Lymph node infarction is very rare, and is frequently associated with neoplasms, such as malignant lymphoma and non-neoplastic disease, or interventions such as fine-needle aspiration (FNA). A 76-year-old-man presented with cervical lymph node swelling. Although FNA was performed, the findings were insufficient for a definitive diagnosis. Consequently, surgical biopsy of the cervical lymph node was performed, which revealed total infarction; a diagnosis of classical Hodgkin lymphoma was made later. Both lymphoma itself and FNA may cause total lymph node infarction, which makes diagnosis confusing. Therefore, it is important to repeat the biopsy rather than repeat FNA to correctly diagnose malignant lymphoma, including Hodgkin lymphoma.

Composite lymphoma is defined as the co-occurrence of two types of lymphoma, comprising 1-4% of lymphomas, and the association of B-cell-type chronic lymphocytic leukemia (B-CLL)/small lymphocytic lymphoma and peripheral T-cell lymphoma (PTCL) is rare. Here, we report a case (77-year-old woman) of advanced B-CLL complicated by newly appearing PTCL. Two years after the onset of B-CLL, CLL cells acquired CD38 antigen expression and the disease entity became CLL/prolymphocytic leukemia. Trisomy 12 and t(14;18) karyotypes were observed. Five years after the onset of B-CLL, large abnormal cells with convoluted nuclei appeared in the peripheral blood and rapidly increased in number. These cells were positive for CD3, CD4, CD5, CD30 (partially), CD56, and αβ-type T-cell receptor (TCR), in which PCR demonstrated monoclonal TCR-γ gene rearrangement. An additional diagnosis of PTCL, not otherwise specified was made. We treated her with an R-CHOP regimen, resulting in the marked reduction of B-CLL cells but progressive PTCL. Brentuximab vedotin had a transient effect, but the patient died of sepsis due to residual PTCL and pancytopenia. This case is highly informative for tumor biology of B-CLL in terms of emergence of both chromosomal abnormalities and PTCL with progression of this leukemia.

Intravascular large B-cell lymphoma (IVLBCL) is a rare and clinically distinctive entity characterized by the almost exclusive growth of large cells within the lumen of blood vessels in particular capillaries. Reports of this peculiar disease, do not commonly address the PD-L1 expression on IVLBCL tumor cells. Here, we describe a 51-year-old Japanese woman who presented with rapidly progressive cognitive decline and higher brain dysfunction. CT scan and MRI revealed multiple ischemic foci in the cerebral hemispheres, ground-glass opacity in the lungs, and splenomegaly. Random skin biopsy for IVLBCL diagnosis yielded negative results. The patient experienced a rapidly deteriorating clinical course with no treatment, and died from the disease after 3 months of hospitalization. Post-mortem examination revealed systemic intravascular plugging of lymphoma cells, without mass lesions in the central nervous system or in visceral organs such as the lungs, liver, pituitary gland, ovaries, and uterus. The tumor cells were positive for CD10, CD20, BCL2, BCL6, and MUM1, but not other lineage-specific markers. Notably, the tumor cells showed strong PD-L1 expression. Our case was diagnosed as IVLBCL with neoplastic PD-L1 expression. These findings suggest that PD-L1 is associated with immune evasion of IVLBCL and may play a role in the pathogenesis and peculiar biological behavior of this unique disease. Additionally, PD-L1 may represent a possible therapeutic target for immune check-point inhibitors.