A case of Degos disease: demonstration of C5b-9-mediated vascular injury.

A 68-year-old Japanese male presented with atrophic erythematous white lesions with peripheral dark reddish rims on his back. Multiple ulcers were detected from his stomach to his large intestine using endoscopy. Although the patient was given high doses of a steroid, aspirin, dipyridamole, and intravenous immunoglobulin therapy, he died of gastrointestinal hemorrhage, perforation and septic shock. An autopsy examination revealed pauci-inflammatory thrombotic microangiopathy with endothelial cell injury, fibrous occlusive arteriopathy, and vascular C5b-9 deposition in the wall of the gastrointestinal tract from the esophagus to the large intestine as well as in the dermis of the skin.

CD20 gene deletion causes a CD20-negative relapse in diffuse large B-cell lymphoma.

In diffuse large B-cell lymphoma (DLBCL), a CD20-negative relapse is clinically significant because it is associated with chemo-refractory phenotypes and loss of a therapeutic target. The alteration of the CD20 gene is reported as infrequent in CD20-negative relapse in B-cell lymphoma. We established a DLBCL cell line with loss of CD20 expression (SD07) from a patient at CD20-negative relapse. She was initially diagnosed with CD20-positive DLBCL and received repeated immuno-chemotherapy that included rituximab. SD07, which has an immunoglobulin κ rearrangement identical to that of lymphoma cells at CD20-negative relapse, showed homozygous deletion of the CD20 gene with loss of the copy number of 11q12. SD07 is the first case in which it is proven that the loss of CD20 expression in relapsed DLBCL is the result of deletion of the CD20 gene. Deletion of the CD20 gene is a molecular mechanism of CD20-negative relapse in a subset of DLBCL.

Follicular tissue fragments in fine-needle aspiration cytology of lymph nodes: A useful clue in differential diagnosis of follicular lymphoma and reactive follicular hyperplasia.

BACKGROUND: In Fine-needle aspiration cytology (FNAC) of lymph nodes, tissue fragments derived from follicular structures may be observed in specimens. We defined such tissue fragments as follicular tissue fragments (FTF), and investigated differences in cytological findings for FTFs of each histological type. METHOD: A total of 41 cases with FNAC of lymph nodes were examined. In these cases, the histopathological diagnoses were reactive lymphoid hyperplasia (RLH) (n = 17), follicular lymphoma (FL) (n = 13), diffuse large B-cell lymphoma (DLBCL) (n = 18), and Burkitt lymphoma (n = 1). Specimens were analyzed for the presence of FTFs, and for tingible-body macrophages (TBMs) and monomorphism of lymphocytes in FTFs. FTFs with a maximum diameter of >500 µm were defined as large-FTFs. RESULTS: FTFs were identified in RLH (14/17, 82.4%), FL (13/13, 100%), and DLBCL (3/18, 16.7%). In the RLH subtypes, FTFs were present only in follicular hyperplasia (FH) (14/15, 93.3%) and not in paracortical hyperplasia (0/2). The number of cases with large FTFs among those with FTFs were as follows: RLH (10/14, 71.4%), FL (11/13, 84.6%), and DLBCL (0/3). Similarly, those with TBMs in FTFs were as follows: RLH (13/14, 92.9%), FL (0/13) and DLBCL (2/3, 66.7%). Monomorphism was observed in RLH (1/14, 7.1%) and FL (11/13, 84.6%), but not in DLBCL (0/3). CONCLUSIONS: Distinction between FL and FH is possible by identifying large-FTFs. In FL, TBMs are absent in FTFs and lymphocytes often show monomorphism. Therefore, recognizing FTFs and observing details inside the FTFs are useful for identification and differential diagnosis of FL and FH in FNAC of lymph nodes.

Increased MYC expression without MYC gene translocation in patients with the diffuse large B-cell-lymphoma subtype of iatrogenic immunodeficiency-associated lymphoproliferative disorders.

Post-transplant lymphoproliferative disorder (PTLD) and other iatrogenic immunodeficiency-associated lymphoproliferative disorders (OIIA-LPD) are iatrogenic lymphoproliferative disorders (LPD) that develop in association with immunosuppressive treatment in the setting of organ transplantation and autoimmune disease, respectively. Each has a spectrum of pathologies ranging from lymphoid hyperplasia to lymphoma. To clarify the characteristics of the diffuse large B-cell lymphoma (DLBCL) subtype in a cohort of 25 patients with PTLD or OIIA-LPD from our institute, we selected 13 with a histological subtype of DLBCL, including 2 cases of PTLD and 11 of OIIA-LPD. The median patient age at diagnosis was 70 years, with a female predominance. Both PTLD cases developed after kidney transplant. Of the patients with OIIA-LPD, 10 had rheumatoid arthritis, 1 had mixed connective tissue disease, and 8 were treated using methotrexate. Both of the PTLD patients and 6 of the OIIA-LPD patients had extranodal manifestations. All patients except for one were classified as having the non-germinal center B-cell (non-GCB) subtype according to the Hans algorithm. Tissue samples from 8 patients were positive for CD30 and 8 were positive for Epstein-Barr virus (EBV)-encoded small RNA. Seven patients had MYC-positive tissue samples, but none had MYC translocation. Our study suggests that extranodal manifestations and the non-GCB subtype are common, that EBV is associated with the DLBCL subtype of PTLD and OIIA-LPD, and that anti-CD30 therapy is applicable. In addition, our patients with the DLBCL subtype of PTLD and OIIA-LPD exhibited MYC overexpression without MYC translocation, suggesting an alternative mechanism of MYC upregulation.

Over-expression of CCL3 MIP-1alpha in a blastoid mantle cell lymphoma with hypercalcemia.

We analyzed a case with the blastoid variant of mantle cell lymphoma (MCL-BV), a rare subtype of B-cell lymphoma, presenting with marked hypercalcemia at diagnosis. Enzyme-linked immunosorbent assay (ELISA) showed elevated serum levels of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), macrophage inflammatory protein-1alpha (MIP-1alpha), and type I collagen telopeptide, but not parathyroid hormone, calcitriol or parathyroid hormone-related peptide at diagnosis, suggesting local osteoclastic hypercalcemia in this case. By reverse transcription polymerase chain reaction (RT-PCR) analysis, we found predominant expression of mRNA for MIP-1alpha in addition to those for receptor-activator of nuclear-factor kappa B ligand (RANKL), TNF-alpha, and IL-6 in lymphoma cells obtained from the patient. Furthermore, recombinant MIP-1alpha significantly stimulated (3)H-thymidine uptake by isolated MCL cells in vitro. Treatment with intravenous fluids, bisphosphonate, and methylprednisolone followed by combination chemotherapy promptly corrects the hypercalcemia and successfully induced complete remission, which was accompanied by a decrease of these cytokines in the serum, including MIP-1alpha. In the present case, MIP-1alpha, an osteoclast-activating factor produced by mantle lymphoma cells, may contribute to the development of hypercalcemia. It likely acts through RANKL expression in tumor cells and/or stroma cells, as indicated in multiple myeloma (MM) and adult T-cell leukemia/lymphoma (ATLL). Furthermore, MIP-1alpha is also involved in the development of an aggressive phenotype on MCL by stimulating proliferation of these lymphoma cells. In summary, the present study demonstrated that MIP-1alpha is an important factor in the development of both hypercalcemia and an aggressive phenotype in some types of B-cell lymphoma.

t(3;14)(p14.1;q32)/FOXP1-IGH translocation in thyroid extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma).

OBJECTIVES: MALT lymphoma occurs in various organs and has several characteristic genetic aberrations. Thyroid MALT lymphoma has been reported to include t(3;14)(p14.1;q32)/FOXP1-IGH as a specific genetic aberration, but the number of studies is limited. METHOD AND RESULTS: We examined 86 thyroid lymphoma cases using fluorescence in situ hybridization (FISH) for the detection of t(3;14)/FOXP1-IGH in formalin fixed paraffin-embedded tissue (FFPE). Histopathological diagnoses of the analyzed specimen were as follows: thyroid MALT lymphoma (n = 59), DLBCL (n = 23), follicular lymphoma (n = 4), and benign lesions (n = 14) included Hashimoto's thyroiditis (n = 13) and other (n = 1). Of the 100 analyzed cases, thirty-six (36 %) thyroid lymphoma cases were positive for t(3;14)/FOXP1-IGH. Thirty-three (55.9 %) of the 59 MALT lymphoma cases were positive for t(3;14)/FOXP1-IGH. Three (13.0 %) of the 23 DLBCL cases were positive for t(3;14)/FOXP1-IGH. All 4 follicular lymphomas examined were negative for t(3;14)/FOXP1-IGH. None of the benign cases was positive for t(3;14)/FOXP1-IGH, including Hashimoto's thyroiditis (0/13) and benign tissue (0/1). CONCLUSIONS: Our study found that t(3;14)/FOXP1-IGH was frequently found in thyroid MALT lymphoma. A detection of t(3;14)/FOXP1-IGH is extremely useful for the differential diagnosis between primary MALT lymphoma of the thyroid and other thyroid disorders.

Clinicopathological comparison of the World Health Organization/Wotherspoon score to the Groupe d'Etude des Lymphomes de l'Adult grade for the post-treatment evaluation of gastric mucosa-associated lymphoid tissue lymphoma.

BACKGROUND AND AIM: The World Health Organization (WHO) has adopted criteria for the histological differential diagnosis of gastric extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (GML) based on the criteria proposed by Wotherspoon in 1993 (WHO/Wotherspoon score). These histological criteria are commonly used by pathologists for initial diagnoses, but have not been adopted uniformly for the post-treatment evaluation of GML. In 2003, the Groupe d'Etude des Lymphomes de l'Adult (GELA) proposed a new histological grading system (GELA grade) in preference to use of the WHO/Wotherspoon score for post-treatment evaluation. In the present study, we compared the WHO/Wotherspoon and GELA systems to examine which histological criterion is better for post-treatment evaluation. METHODS: Fourteen cases of GML under long-term follow up were initially diagnosed according to the WHO criteria with detailed immunohistology, and were periodically evaluated with both histological criteria after anti-Helicobacter pylori treatment. They were also evaluated based on histological stromal changes accompanying the disappearance of lymphoma tissue. RESULTS: The study showed strong similarities between the WHO/Wotherspoon and GELA systems and no clear advantage of either system for post-treatment evaluation. The GELA grade could not be used for the evaluation of changes in the degree of lymphoma infiltration from pre- to post-treatment because the four-item scale is not comparable with the formal six-point WHO/Wotherspoon scale. Stromal changes in the lamina propria, including an empty appearance and fibrosis, were correlated with lymphoma reduction after treatment and appear to be good indicators for post-treatment evaluation. CONCLUSION: We propose the utilization of the WHO/Wotherspoon score accompanied by the assessment of stromal changes for the post-treatment evaluation of GML.

Impact of CD123 expression, analyzed by immunohistochemistry, on clinical outcomes in patients with acute myeloid leukemia.

Aberrant expression of the interleukin-3 receptor alpha chain (IL3RA or CD123) is frequently observed in patients with a subset of leukemic disorders, including acute myeloid leukemia (AML), particularly in leukemia stem cells. We analyzed the relationships between immunohistochemical (IHC) expression, including that of CD123, and clinical outcomes. This study involved a retrospective analysis of 48 patients diagnosed with de novo AML (M0-M5, n = 48) at our hospital between February 2008 and September 2015. Among patients with de novo AML, CD123 expression was associated with a failure to achieve complete response (CR) to initial induction chemotherapy (P = 0.044) and poor overall survival (OS) (P = 0.036). This is the first study using IHC to demonstrate that CD123 expression is associated with a poor CR rate and poor OS in de novo AML patients. These results support previous reports using flow cytometry (FCM). CD123 expression may thus be useful for assessing AML patients' prognoses. At the time of diagnosis, CD123 expression analysis using IHC may represent a clinically useful assessment for de novo AML patients.

Histopathology of bone marrow reconstitution after umbilical cord blood transplantation for hematological diseases.

To study hematopoietic reconstitution in umbilical cord blood transplantation (CBT), bone marrow (BM) histology was investigated in 35 biopsies after bone marrow transplantation (BMT) and in 40 biopsies after CBT. BM biopsies were obtained at different times after transplantation and were evaluated for cellularity, number of megakaryocytes and CD34-positive cells, and fibrosis. In biopsies up to 29 days after BMT, cellularity was increased and megakaryocytes were observed, but at 29 days after CBT, biopsies showed severe cellular depletion and almost no megakaryocytes. In addition, fewer CD34-positive cells were observed after CBT compared to after BMT. After day 30 after CBT, hematopoietic recovery of the BM was gradually observed and after day 100 after transplantation, no essential differences were observed between BMT and CBT. Hematopoietic recovery of the BM after CBT was delayed compared to that after BMT, but engraftment of donor cells after CBT was also observed in histopathologically. To the best of the authors' knowledge this is the first histopathological description of BM reconstitution after CBT.

Immunohistochemical CD73 expression status in gastrointestinal neuroendocrine neoplasms: A retrospective study of 136 patients.

The WHO 2010 classification divides gastrointestinal neuroendocrine neoplasms (GI-NENs) into neuroendocrine tumor (NET) G1, NET G2, neuroendocrine carcinoma (NEC) and mixed adenoendocrine carcinoma (MANEC) groups. A total of 136 cases of GI-NENs diagnosed at our hospitals as gastrointestinal carcinoids, endocrine cell carcinomas and NENs over the last 11 years, using the WHO 2010 classification were assessed. Among the 136 cases, 88.2% (120/136) were classified into the NET group (NET G1/G2) and 11.8% (16/136) were classified into the NEC group (NEC/MANEC). The incidences of lymphatic and venous invasions were higher in the NEC group compared with in the NET group (P<0.0001 and P=0.0021, respectively). The immunohistochemical staining of cluster of differentiation 73 (CD73) was evaluated in GI-NENs. CD73 is a potentially useful molecule in tumor immunity. In general, CD73 on the tumor cell membrane converts adenosine monophosphate to adenosine, which restrains the production of interferon-γ and cytocidal activity. Although the association between stem cells of pancreatic NENs and CD73 has been reported, few studies have reported on CD73 expression in GI-NENs. Immunohistochemical CD73 expression on the cytomembrane of neuroendocrine cells was detected in 27.2% (37/136) of the GI-NENs. The positive ratio of CD73 was significantly higher in the NEC group compared with in the NET group (P=0.0015). CD73 is also considered as a potential biomarker of anti-programmed death-1 (PD-1) therapy. The expression of programmed death-ligand 1 (PD-L1) on the cytomembrane of GI-NENs was assessed. The positive ratio of PD-L1 was higher in the NEC group compared with in the NET group (P=0.0011). Furthermore, CD73 expression status was significantly correlated with PD-L1 expression (P<0.0001). These results indicate that CD73 may be an interesting candidate for a biomarker for certain prognostic factors and therapeutics concerning PD-1 therapy.

Ki-67 expression of immunohistochemistry using computerized image analysis is a useful prognostic marker in follicular lymphomas.

Ki-67 is a useful proliferation marker in various tumors including lymphoma. In general, the number of Ki-67 positive cells in immunohistochemistry (IHC) is counted manually for routine pathological diagnosis. However, a manual count is subjective and time consuming. Currently, image analysis is often used for the quantification of positive cells in tissue in IHC. Thus, to determine the pathological prognostic factors for follicular lymphoma (FL), we studied the relationship between Ki-67 expression in IHC and the treatment effect and prognosis using image analysis software. We analyzed 82 newly-diagnosed patients with FL. All patients were treated with rituximab-containing regimens. The median Ki-67 expression was 17.0%. A high expression of Ki-67 tended to be associated with short overall survival (P = 0.058). Moreover, Ki-67 expression was significantly lower in patients with FL grade 1-2 than in those with FL grade 3a. This study suggests that image analysis provides an accurate, reproducible, and easy method of measuring Ki-67 expression in IHC in FL, and is possibly a useful marker for treatment selection or prognosis prediction in FL.

The GCB subtype of diffuse large B-cell lymphoma is less frequent in Asian countries.

Patients with the germinal center B-cell-like (GCB) subtype of diffuse large B-cell lymphoma (DLBCL) have a significantly better survival rate than those with non-GCB DLBCL. Several studies have examined the proportions of GCB and non-GCB subtypes in large series of DLBCL patients, but it remains unclear if these proportions are the same in different countries. We performed an immunohistochemical analysis of the numbers of GCB and non-GCB subtypes in a large number of patients with DLBCL in Japan and compared the results with literature data for other countries. We found that 71 of 248 patients (29%) had the GCB phenotype and 177 patients (71%) had the non-GCB subtype of DLBCL among our patient population. Assessment of data collected from other studies showed that 31% of DLBCL patients (102/330) have the GCB subtype in Asian countries, but 50% (206/416) express GCB phenotypes in Western countries; based on these data, the occurrence of the GCB subtype of DLBCL was significantly less in Asian countries (p<0.001). Since patients with the GCB phenotype of DLBCL have better survival, future studies of DLBCL should recognize the difference in the proportions of GCB and non-GCB subtypes of DLBCL between Asian and Western populations.

Rare Case of Cecal Signet Ring Cell Carcinoma with Distal Intramural Spread.

In this paper, we report a rare case of cecal Signet ring cell carcinoma (SRCC) with Distal intramural spread (DIS) along with a review of the literature. A 71-year-old woman suffering from vomiting, abdominal pain, and abdominal distension was admitted to a hospital and was suspected to have ileus. She was transferred to our hospital and diagnosed with cecal cancer with intestinal obstruction. Laparotomy was performed, after which she was diagnosed with cecal SRCC by histopathological examination. A submucosal lesion was located 55 mm from the distal side of the main tumor. This lesion was also diagnosed as SRCC. It was not exposed to the epithelium or the serous membrane. The submucosal tumor was diagnosed as DIS of cecal SRCC. After the operation, she underwent chemotherapy with FOLFIRI+Cet (5-fluorouracil, leucovorin, and irinotecan plus cetuximab). At a follow-up examination nine months after surgery, she was found to be doing well.

Hypermethylation of CpG islands in p16 as a prognostic factor for diffuse large B-cell lymphoma in a high-risk group.

PURPOSE: The aim of the study was to analyze the methylation status of the promoter regions of p15 and p16 and to assess the prognostic significance of promoter hypermethylation in diffuse large B-cell lymphoma (DLBCL). EXPERIMENTAL DESIGN: DLBCL was diagnosed by morphology and immunohistochemical analysis according to the World Health Organization (WHO) classification. The methylation status of CpG islands in the p15 and p16 promoters was analyzed by methylation-specific polymerase chain reaction in 49 DLBCLs. RESULTS: Hypermethylation of the p15 and p16 promoters was detected in 20 (41%) and 22 (45%) of the 49 DLBCLs, respectively. Among all patients with DLBCL, there was no significant difference in the overall survival between those with hypermethylated and unmethylated p15 (P=0.442) or between those with hypermethylated and unmethylated p16 (P=0.468). Therefore, methylation was analyzed in combination with evaluation of clinical features using the international prognostic index (IPI). In the high-intermediate-risk and high-risk groups, patients with hypermethylated p16 had significantly lower survival rates than those of patients in the same risk group with unmethylated p16 (P=0.010). CONCLUSIONS: Our results suggest that hypermethylation of the p16 promoter indicates a poor prognosis in high-intermediate-risk and high-risk DLBCL patients, and may be a useful marker for selection of appropriate treatment when used in conjunction with the IPI.

Disappearance of CD21-positive follicular dendritic cells preceding the transformation of follicular lymphoma: immunohistological study of the transformation using CD21, p53, Ki-67, and P-glycoprotein.

Some follicular lymphomas histologically transform into diffuse aggressive lymphomas, the prognosis of which is poor. There are, however, no reliable histological criteria for predicting which cases will later undergo such transformation. In low-grade B-cell lymphomas, follicular dendritic cells form dense mesh-like networks that contain accumulating neoplastic B-cells. These are rare in high-grade lymphomas. We immunohistochemically analyzed CD21-positive follicular dendritic cells in 32 follicular lymphomas, including 3 transformed lymphomas, in addition to immunohistological study using P-glycoprotein, p53, and Ki-67. We found that the mesh-like networks in follicles are more clearly defined in low-grade lymphomas than in high-grade lymphomas (p = 0.015). Neoplastic follicles in 2 transformed lymphomas lost the networks of follicular dendritic cells before transformation despite the existence of morphologically clear follicles. This differed from the non-transformed cases of the same cytological grades. Prognosis was statistically better for patients with low-grade tumor than for those with high-grade tumor (p = 0.026), and there was a trend toward poorer survival among CD21-negative cases (p = 0.186). P-glycoprotein, p53, and Ki-67 expressions did not provide sufficient information to predict the transformation of follicular lymphoma. The presence of CD21-positive follicular dendritic cells in neoplastic follicles might help predict the potential of follicular lymphoma to transform to diffuse large B-cell lymphoma.

Elevation of carcinoembryonic antigen coinciding with disease activity of ulcerative colitis.

We report on three cases of ulcerative colitis who presented with increased levels of serum carcinoembryonic antigen (CEA) during the active stage. All cases were pancolitis with a moderate to severe disease course. After remission induction with medical therapies, serum CEA levels decreased to the normal reference range. Immunohistochemical analyses demonstrated the existence of CEA not only along with the apical surface of the colonic epithelia but also at the cytosol of the inflamed epithelia where goblet cells were depleted during the active stage. We speculate that CEA was up-regulated by inflammatory response particularly in the process of epithelial regeneration.

Primary pulmonary classical hodgkin lymphoma with two recurrences in the mediastinum : a case report.

We report a case of primary pulmonary classical Hodgkin lymphoma (CHL) in a 58-year-old woman. Twelve years ago, the patient complained of slight fever and weight loss. A mass of about 5 cm in diameter was seen in the right lung on radiography and computed tomography (CT). Right total pneumonectomy and resection of mediastinal lymph nodes were performed. A pathological examination led to a strong suspicion of Hodgkin disease (HD) (now referred to as CHL), but a definite diagnosis could not be made at the time. Six years later, a chest CT showed a tumor around the ascending aorta, which was treated successfully by radiation therapy. Six years later, the chest CT revealed a tumor in the anterior mediastinum. CHL was diagnosed based on an immunohistochemical re-examination of lung specimens resected 12 years earlier and CT-guided fine needle tumor biopsy specimens of the second recurrent tumor in the anterior mediastinum were compatible with the recurrence of CHL. Therefore, we diagnosed this case as primary pulmonary CHL that later relapsed in the mediastinum. The tumor size was reduced by radiation therapy and the patient is currently under observation as an outpatient.

Senile EBV-associated B-cell lymphoproliferative disorder of indolent clinical phenotype with recurrence as aggressive lymphoma.

Senile EBV-associated B-cell lymphoproliferative disorder (LPD) was proposed as a new disease entity in 2003. This condition has a high incidence in elderly people without underlying immunodeficiencies, and is characterized by EBV-positive B-cell proliferation with a polymorphic composition. Histologically, the disease has two subtypes. The polymorphic LPD (PLPD) subtype has a preferable prognosis, whereas the large cell lymphoma (LCL) subtype involves aggressive disease progression. Reported herein is a case of senile EBV-BLPD with indolent clinical features and PLPD subtype in the initial phase that recurred as an aggressive lymphoma 3 years after the initial diagnosis. In the recurrent phase, Southern blotting confirmed monoclonal proliferation of large lymphoid B-cells. In both the initial and recurrent phases, polymerase chain reaction (PCR) yielded a single discrete band of a similar size due to an immunoglobulin heavy-chain gene rearrangement, indicating that the large lymphoid B-cells retained identical monoclonality throughout the histological progression and over the whole clinical course. These results suggest that the PLPD subtype is a histological finding in early phase senile EBV-BLPD and that the LCL subtype reflects the progressive phase of the disease.

Histopathological bone marrow changes after reduced-intensity hematopoietic stem cell transplantation for follicular lymphoma involving bone marrow.

Allogeneic stem cell transplantation (allo-SCT) is used as curative therapy for malignant lymphoma, and reduced-intensity hematopoietic stem cell transplantation (RIST) is sometimes performed to avoid the toxicity and mortality associated with myeloablative allo-SCT. RIST is generally preferred for elderly patients with malignant lymphoma. A 62-year-old woman with follicular lymphoma (FL) involving bone marrow (BM) suffered relapse after autologous SCT. RIST was performed; cells were from an unrelated, fully human leukocyte antigen-matched donor. To study the hematopoietic reconstitution, BM biopsy specimens that were obtained at different times after RIST, were evaluated. Engraftment of donor cells was observed on days 19 and 48 after RIST, and residual FL in BM had completely disappeared by day 73 after RIST. This is the first report to document histological BM regeneration after RIST and disappearance of FL involving the BM.