肝脏炎性假瘤与炎性假瘤样滤泡树突状细胞肿瘤的病理学诊断

目的探讨肝脏炎性假瘤及肝脏炎性假瘤样滤泡树突状细胞肿瘤的临床病理学特征及诊断、鉴别诊断要点。方法对肝脏炎性假瘤及肝脏炎性假瘤样滤泡树突状细胞肿瘤各1例进行临床病理分析、免疫组织化学染色及EBV-encoded RNA（EBER）原位杂交检测。结果肝脏炎性假瘤的临床症状包括右上腹不适或疼痛、发热、肝肿大、体重减轻等。大体肿瘤呈实性,境界清楚;镜下肿瘤细胞呈梭形,波浪状排列,其间可见大量淋巴细胞及浆细胞浸润以及散在分布的大的多形性细胞。核仁明显。肝脏炎性假瘤样树突状细胞肿瘤的临床症状、影像学表现及镜下表现均与肝脏炎性假瘤十分相似。但肿瘤细胞边界不清,胞质嗜酸性,除R—S样细胞外,还可见到不少形态怪异的巨细胞,且免疫表型CD21、CD35阳性。EBER（EBV—encoded RNA原位杂交）阳性。结论肝脏炎性假瘤样滤泡树突状细胞肿瘤是罕见的肿瘤,诊断时需注意与肝脏梭形细胞肿瘤甚至霍奇金淋巴瘤鉴别,树突状细胞免疫标记CD21、CD35阳性,特别是EBER原位杂交阳性有助于诊断。     

Immunohistochemical spectrum of GISTs at different sites and their differential diagnosis with a reference to CD117 (KIT).

Gastrointestinal (GI) stromal tumor (GIST) is the designation for the major subset of GI mesenchymal tumors and encompasses most tumors previously classified as GI smooth muscle tumors. Although GISTs typically express CD117 (KIT), often express CD34, and sometimes express alpha-smooth muscle actin (SMA), the relative frequency of these markers has not been characterized in large series of GISTs of different sites, and the CD117 expression has not been fully characterized in intra-abdominal tumors. In this study, we immunohistochemically analyzed 292 GISTs throughout the GI tract, including omentum and mesentery, and compared the immunoreactivities with 211 other tumors that may enter in the differential diagnosis. GISTs were defined in this study as CD117-positive primary spindied or epithelioid mesenchymal tumors of the GI tract, omentum, or mesentery. The CD34 positivity of GISTs varied from 47% in small bowel to 96 to 100% in rectum and esophagus, whereas SMA expression showed the opposite patterns and was most frequent in the GISTs of small bowel (47%) and rarest in the GISTs of rectum and esophagus (10-13%). Desmin was seen only occasionally. S100 positivity was rare but was seen most frequently in small intestinal GISTs (15%). True leiomyomas from esophagus, muscularis mucosae of colorectum, and pericolic leiomyomas similar to uterine leiomyomas were negative for CD117 and CD34 and positive for SMA and desmin (46 of 46). Inflammatory fibroid polyps of stomach and small intestine were negative for CD117 but were often positive for CD34 (6 of 8) and variable for SMA (3 of 8). Inflammatory myofibroblastic tumors involving gastric or colonic wall were negative for CD117 but some showed CD117-positive endothelia. GI schwannomas were all negative for CD117 and positive for S100 protein (11 of 11). Extremely focal CD117 positivity was seen in the neoplastic cells of some retroperitoneal leiomyosarcomas and liposarcomas. Among other CD117-positive tumors were intestinal metastatic melanomas (8 of 11) and extraskeletal Ewing's sarcomas (5 of 11), two of which were abdominal. In conclusion, strong CD117 expression defines most primary GI mesenchymal tumors as GISTs, which show different patterns for CD34 and SMA in various parts of the GI tract. Some unrelated CD117-positive tumors (melanomas, Ewing's sarcomas) should not be confused with GISTs.     

Mediastinal follicular dendritic cell sarcoma involving bone marrow: a case report and review of the literature

We report a rare case of mediastinal follicular dendritic cell (FDC) sarcoma involving the bone marrow. The patient, a 46-year-old woman, had a clinically aggressive tumor in the anterior mediastinum that was initially diagnosed as a diffuse B-cell lymphoma. She received chemotherapy but showed no significant improvement. One year later, the patient presented at our institution with pelvic bone metastases. Biopsy specimens of the sacrum lesion and bone marrow were obtained. The diagnosis of FDC sarcoma was made based on histological examination and immunohistochemical findings, including strong positive staining of tumor cells for CD21, CD23, clusterin, and epidermal growth factor receptor (EGFR) and negative staining for CD20, CD30, CD45, CD1a, S-100, vimentin, and keratin cocktail. Histological examination and immunohistochemical studies of a previous biopsy of the mediastinal mass confirmed the diagnosis of mediastinal FDC sarcoma. The patient was treated with an appropriate chemotherapy regimen; 1 month later, follow-up bone marrow biopsy revealed no tumor cells. Although FDC sarcoma is considered a low-grade tumor, the tumor in the present case not only developed at an unusual location with bone metastasis but also involved bone marrow. To our knowledge, this is the first such case ever reported. This case also highlights the utility of EGFR as an immunohistochemical marker of dendritic cell tumors that could be used as a diagnostic tool and guide for choosing appropriate chemotherapy regimens.     

Extranodal follicular dendritic cell sarcoma of the head and neck region: three new cases, with a review of the literature.

Extranodal follicular dendritic cell (FDC) sarcoma of the head and neck region is uncommon, with 16 well-documented cases previously reported (four in the tonsil, four in the pharynx, two in the palate, five in the soft tissue, and one in the thyroid). We here report an additional three cases of extranodal FDC sarcoma in the tonsil (two cases) and pharynx (one case). In these new cases, the neoplastic cells were arranged in diffuse, fascicular, and vaguely whorled growth patterns. A background lymphocytic infiltrate was sprinkled throughout the neoplasms, with focal prominent perivascular cuffing. Scattered multinucleated giant cells were present. Immunohistochemically, tumor cells were strongly and diffusely positive for follicular dendritic cell markers CD21 and CD35. Tumor cells were diffusely positive for fascin and negative for leukocyte common antigen, S-100 protein, cytokeratin, and Epstein-Barr virus (EBV) latent membrane protein-1 (EBV-LMP). EBV was also not detected in the tumor cells by in situ hybridization for EBV-encoded RNAs. FDC sarcomas are probably an underrecognized neoplasm, especially when they occur in extranodal sites in the head and neck region. Two of the three new cases we report were initially misdiagnosed, and five cases of extranodal FDC sarcoma in the head and neck region reported in the recent literature were initially misdiagnosed. Our aim is to complement the current understanding of this neoplasm and alert pathologists to this rare entity in this region to avoid misdiagnosis. Recognition of extranodal FDC sarcoma requires a high index of suspicion, but this tumor has numerous distinctive histological features that should bring the neoplasm into the differential diagnosis. Confirmatory immunohistochemical staining with follicular dendritic cell markers such as CD21 and/or CD35 is essential for the diagnosis. Correct characterization of this neoplasm is imperative given its potential for recurrence and metastasis.     

网膜和肠系膜胃肠道外间质瘤的临床病理研究

目的 研究网膜和肠系膜胃肠道外间质瘤(EGIST)临床病理和免疫组织化学标记特点,并探讨其组织来源、预后评价及与胃肠道间质瘤(GIST)的关系。方法 运用形态学和免疫组织化学(CD117、CD34等)研究19例网膜和肠系膜原诊断为平滑肌肿瘤、许旺瘤的间叶性肿瘤。结果 共诊断14例EGIST,其中网膜6例,肠系膜8例。肿瘤大小3．5～29．0cm(平均12．4cm)。梭形细胞为主型9例,上皮样细胞为主型2例,混合型3例。免疫组织化学阳性表达结果：CD117(14／14)、CD34(8／14)、α-平滑肌肌动蛋白(6／14)。结蛋白、S-100蛋白均阴性。随访结果：6例网膜EGIST均无瘤生存;7例肠系膜EGIST3例死于肿瘤,1例带瘤生存,3例无瘤生存。结论 EGIST与GIST为同一性质肿瘤,可能共同起源于多分化潜能的间叶干细胞或肿瘤向卡哈尔间质细胞分化。EGIST有独特的行为谱,预后评价不能完全套用GIST的评价指标。     

CD4+CD56+ lineage negative hematopoietic neoplasm: so called blastic NK cell lymphoma

Blastic natural killer (NK) cell lymphoma is a rare neoplasm characterized by blastoid tumor cells expressing CD4 and CD56, with predominant skin involvement. Although this tumor has been regarded as a neoplasm related to NK cell, recent studies suggested that it is derived from plasmacytoid dendritic cells, but not from NK cell. Herein we report 4 cases of CD4+CD56+ lineage marker-blastic NK cell lymphomas with a review of literatures. The patients were 3 men and one woman. Three of them were young (17, 18, and 22 yr old). Three patients had skin lesions, at initial presentation in two patients and during the course of disease in other patient. Histologically, tumors consisted of monotonous medium to large blastoid cells showing no necrosis, angiocentric growth or epidermotrophism. All four tumors were CD4+ and CD56+. Three expressed CD68 antigen. Lineage specific markers for B- and T cell were negative. All tumors did not express myeloperoxidase. T-cell receptor gene rearrangement, EBV, CD13 and CD33 were negative. In one patient, tumor cells arranged in Homer-Wright type pseudorosette and expressed terminal deoxynucleotidyl transferase(TdT). Despite the standard lymphoma chemotherapy, the tumors, except one lost during follow-up, progressed and relapsed. The patients died 8-60 months after diagnosis.     

Small intestinal angiosarcoma leading to perforation and acute abdomen: a case report and review of the literature

A 76-year-old man presented to the emergency room with abdominal pain and fatigue. The patient had a history of gastrointestinal bleeding. An abdominal computed tomographic scan showed collections of free air in the abdomen with obstruction of the distal small intestine and multiple masses in the liver. Laparotomy revealed a widespread malignant neoplasm in the abdomen, with multiple tumor nodules in the ileal wall, mesentery, and liver. The ileal wall was perforated within the area of one of the tumors. Pathologic examination of the lesion showed a neoplasm composed of solid sheets of spindle and undifferentiated cells, forming interlacing delicate vascular channels with atypical endothelial cells. The tumor cells were positive for the endothelial marker CD31, whereas reactivity for a broad panel of epithelial and other endothelial markers was negative. This case demonstrates that although angiosarcomas of the gastrointestinal tract are rare, they should be considered in cases of intestinal perforation or severe bleeding, especially in the elderly. A broad panel of immunochemical markers might be necessary to establish the pathologic diagnosis.     

Epidermal growth factor receptor expression in follicular dendritic cells: a shared feature of follicular dendritic cell sarcoma and Castleman's disease

The factors regulating the growth of follicular dendritic cell (FDC) sarcoma are currently unknown. Using cDNA microarray analysis, we found that the epidermal growth factor receptor (EGFR) is expressed in FDC sarcoma. We immunohistochemically examined the expression of EGFR in a larger series of FDC sarcomas and in nonneoplastic FDCs. This included 8 cases of FDC sarcoma, 12 cases of hyaline vascular Castleman's disease (CD), 5 cases of human herpesvirus 8 (HHV8)-positive plasma cell CD, 7 cases of HHV8-negative plasma cell CD, 13 cases of reactive lymph nodes, 3 cases of reactive tonsils, 10 cases of follicular lymphoma, 6 cases of nodular mantle cell lymphoma, and 6 cases of angioimmunoblastic T-cell lymphoma. EGFR was expressed in tumor cells in 7 of 8 cases (88%) of FDC sarcoma (strongly in 4 cases and moderately in 3 cases). The single EGFR-negative case had an anaplastic appearance and a more aggressive clinical behavior. EGFR was also expressed by FDC in all types of CD (strongly in 4 cases, moderately in 16 cases, and weakly in 4 cases). Immunostaining results were negative or only weakly positive for EGFR in FDC of reactive lymph nodes and tonsils, and in the FDC networks of follicular lymphoma, mantle cell lymphoma, and angioimmunoblastic lymphoma. The up-regulation of EGFR in FDC of CD was paralleled by an increase in EGFR expression in the surrounding perifollicular fibroblastic reticulum cells suggesting coordinate regulation. These findings identify a differentially expressed growth regulatory receptor common to both FDC sarcoma and CD, identifying a target for possible therapy in unresectable or refractory cases.     

Extranodal NK/T‐cell lymphoma,nasal type of the uterine cervix: A case report

We report a rare case of extranodal NK/T‐cell lymphoma, nasal type of the uterine cervix that showed cytologic features mimicking cervical cancer. A 65‐year‐old woman presented with vaginal bleeding. Gynecological examination revealed a bulky tumor of the cervix. A conventional Papanicolaou‐stained cervical smear showed hypercellularity consisting of numerous variably sized cohesive clusters that mimicked epithelial tumors, with a necrotic and inflammatory background. A small number of individually scattered cells were also identified. These scattered cells showed pleomorphic, often cleaved, or horseshoe‐shaped nuclei and pale cytoplasm. Biopsy specimens revealed a diffuse growth of atypical cells with an angiocentric pattern. Extensive necrosis and infiltration of inflammatory cells were present. There were numerous mitotic figures. The tumor cells were positive for CD45RO, CD3ε, CD56, granzyme B, TIA‐1, CD7, and Epstein–Barr virus (EBV)‐encoded small RNA (EBER) by in situ hybridization, and negative for cytokeratin, chromogranin A, synaptophysin, CD4, CD5, CD8, CD20, and CD30. Based on these findings, this tumor was diagnosed as extranodal NK/T‐cell lymphoma, nasal type of the uterine cervix. Diagn. Cytopathol. 2016;44:430–433. © 2016 Wiley Periodicals, Inc.     

Follicular lymphoma of the skin and superficial soft tissues associated with a prominent follicular dendritic cell proliferation: an unusual pattern which may represent a diagnostic pitfall

We describe two elderly patients with follicular lymphoma (FL) involving the skin and superficial soft tissues, with a striking proliferation of follicular dendritic cells (FDC). In addition, one patient had bone marrow involvement by FL. Histopathologically, the most remarkable feature in both cases seen at low magnification was a striking pallor of the constituent cells, which were arranged in fascicles, whorls, and round islands. The majority of the cells had the typical cytologic features of FDCs. They were intimately intermingled with centroblasts and centrocytes. A large amount of the clear cytoplasm and the pale nuclei of FDCs, which predominated in the tumors, caused the striking overall pallor of the lesions. Small reactive lymphocytes were scattered between the fascicles. A vague follicular growth pattern was seen only focally. The mantle zones were markedly reduced or absent so that the follicles were seen lying unseparated. The close intermixture of the FDCs and the germinal center cells was responsible for the FDCs appearing to be decorated with B-associated marker, and the germinal center cells seemed to be stained to some degree with FDC-markers. The tumor bulk demonstrated a diffuse and strong reaction with CD10, CD20, CD21, CD35, and stained weakly with CD79a. Fascin and CD23 showed only a weak and focal staining pattern. Bcl-2 decorated large centroblasts and small reactive T-cells. The tumor bulk was negative for actin, EMA, cytokeratins, vimentin, desmin, and factor XIIIa. The proliferative index was rather low; MIB-1 mainly decorated large centroblasts. No monoclonal rearrangement of IgH genes was detected. Epstein-Barr virus was not identified. Electron microscopy revealed typical features of FDCs intermingled with germinal center cells. Such cases may represent a diagnostic pitfall, as FDC overgrowth can mask FL and give the neoplasm the appearance of FDC sarcoma/tumor. We believe that, in both cases, the FDC proliferation had a reactive character.     

Hepatic angiomyolipoma resembling an inflammatory pseudotumor of the liver. A case report

Hepatic angiomyolipoma (AML) may demonstrate a marked histologic diversity and is frequently misdiagnosed. HMB45 is a promising marker for this tumor and is expected to facilitate the recognition of some AMLs with unusual morphology. We report on a case of hepatic AML exhibiting histologic features that were similar to inflammatory pseudotumor (IPT) or to IPT-like follicular dendritic cell (FDC) tumor of the liver. The patient was a 21-year-old Japanese woman with a mass in the left lobe of the liver (70 x 73 mm). There were no clinical features of tuberous sclerosis. Histologically, numerous inflammatory cells, including small lymphocytes, plasma cells, and histiocytes, showed diffuse infiltration throughout the lesion. However, the present case also shared some of the morphologic findings of hepatic AML, including clusters of smooth muscle cells with clear cytoplasm, a few scattered adipose cells, and thick-walled blood vessels. Moreover, the smooth muscle cells consisted of spindle-shaped cells or larger, more rounded cells with either clear cytoplasm or eosinophilic epithelioid cell features positive for vimentin, muscle-specific actin, and smooth muscle actin. HMB45 immunostaining confirmed the diagnosis of AML. The present case indicates that IPT or IPT-like FDC tumor should be added to the list of differential diagnoses for AML of the liver.     

钙化性纤维性肿瘤4例临床病理学分析

目的 探讨钙化性纤维性肿瘤(calcifying fibrous tumor,CFT)的病理形态学特点、免疫组化表达及鉴别诊断.方法 对4例CFT进行免疫组化检测并文献复习.结果 本组患者年龄19～33岁,发病部位分别为胃、纵膈、大网膜及肠系膜根部.镜下可见在大量胶原化的纤维组织内伴有钙化或砂砾体形成,淋巴细胞、浆细胞散在浸润.免疫组化标记瘤细胞表达vimentin,而CD117、CD34、CD99、desmin、S-100蛋白、SMA、actin、NFP、ALK1、ER、PR、CK、BCL-2及Ki-67均阴性.结论 CFT是一种极少见的良性纤维性肿瘤,其诊断需要结合年龄、组织学形态及免疫组化等特点,还需与钙化性腱膜纤维瘤、钙化性肉芽肿、纤维瘤病、胃肠道间质瘤、炎性肌纤维母细胞瘤、结节性筋膜炎和淀粉样瘤等相鉴别.     

Inflammatory pseudotumor‐like follicular dendritic cell sarcoma of the spleen: A report of six cases with increased IgG4‐positive plasma cells

Inflammatory pseudotumor (IPT)‐like follicular dendritic cell (FDC) sarcoma is a rare neoplasm typically occurring in the spleen or liver. We present six cases of EBV⁺ IPT‐like FDC sarcoma of the spleen among Koreans along with their clinicopathologic features and IHC results. Most patients presented with an asymptomatic, incidentally detected single splenic mass and were successfully managed by splenectomy alone. Concomitant disease was found in one case, showing EBV⁺ gastric carcinoma with lymphoid‐rich stroma. Histologic features showed fibro‐inflammatory lesions that were often accompanied by necrosis and epithelioid histiocytic collection, which are barely distinguishable from IPT. Tumor cells did not frequently express conventional FDC markers, including CD21 (3/6 positive cases), clusterin (4/6), and D2‐40 (2/6), but showed uniform positivity for smooth muscle actin (SMA). Noticeably, significant numbers of IgG4⁺ plasma cells were found within all six tumors. We suggest that the diagnosis of IPT‐like FDC sarcoma should be made by the application of a panel of FDC markers, and CD21 negativity or SMA positivity cannot be the criterion for exclusion of IPT‐like FDC sarcoma. Relationship of IPT‐like FDC sarcoma of the spleen and IgG4‐related sclerosing disease should be investigated in further studies.     

Calcifying fibrous 'pseudotumor': clinicopathologic study of 15 cases and analysis of its relationship to inflammatory myofibroblastic tumor

Calcifying fibrous pseudotumor (CFP) has been postulated to be a "late" stage of inflammatory myofibroblastic tumor (IMT). We analyzed 15 cases (8 females and 7 males; aged 1 to 65 years). The anatomic distribution was wide, including 3 cases each in neck, mesentery/omentum, and GI tract and 2 cases each in mediastinum and paratesticular sites. Follow-up information was available in 10 patients (range 4 to 228 months). Local recurrence occurred in 3 patients and was repeated in 2. Tumor size ranged from 0.6 to 25 cm. Lesions were well-circumscribed hypocellular spindle cell proliferations with dense stromal collagen, a lymphoplasmacytic infiltrate, and stromal calcifications. Features of conventional IMT were not seen. Immunostaining showed CD34 positivity in most cases as well as rare cells positive for smooth muscle actin and desmin, and consistent negativity for ALK-1 and S-100 protein. These findings suggest that CFP is a distinctive benign mesenchymal neoplasm with a low risk for recurrence and, therefore, best labelled as "calcifying fibrous tumor." There is no convincing evidence to support an association between CFP and IMT.     

Follicular dendritic cell sarcoma mimicking giant cell carcinoma of the pancreas

Extranodal follicular dendritic cell (FDC) tumors are rare. Recognition of the morphological spectrum of FDC tumors is important to clinical diagnosis. Herein is presented a case of pancreatic FDC sarcoma with unusual clinicopathological features. A 64-year-old male patient presented with weight loss, poor appetite, abdominal fullness, mild anemia and mild peripheral eosinophilia. Histologically, the tumor was composed of both epithelioid and spindle cells with abundant intracytoplasmic hyaline globules. These tumor cells were positive for CD21, CD23, CD35, S-100 protein, fascin and clusterin. Both epithelioid and spindle tumor cells independently colonized the liver and formed two tumor nodules 18 months after the initial resection. Notably, the two hepatic metastases additionally acquired patchy expression of human leukocyte antigen-DR. The epithelioid FDC in one of the hepatic lesions transformed into numerous bizarre giant cells, which could easily be confused with a metastatic giant cell carcinoma from the pancreas. FDC tumor should therefore be included in the differential diagnoses when dealing with a giant cell tumor.     

Podoplanin (D2-40) is a novel marker for follicular dendritic cell tumors

Podoplanin, recognized by monoclonal antibody D2-40, may be a useful marker for follicular dendritic cell (FDC) tumors. Paraffin sections of 125 dendritic cell, histiocytic, and spindle cell lesions were studied, including 11 FDC tumors, 5 interdigitating dendritic cell tumors, 10 histiocytic sarcomas, 5 Langerhans cell histiocytosis, 5 sinus histiocytosis with massive lymphadenopathy, 5 inflammatory pseudotumors of lymph node or spleen, 9 nodal Kaposi sarcomas, 6 inflammatory myofibroblastic tumors (IMTs), 29 gastrointestinal stromal tumors (GISTs), and 10 cases each of malignant peripheral nerve sheath tumor, leiomyosarcoma, monophasic synovial sarcoma (SS), and solitary fibrous tumor. All FDC tumors and Kaposi sarcomas showed strong immunoreactivity for podoplanin (predominantly membranous). Podoplanin expression was only occasionally observed in the other tumor types, including 7 GISTs (24%), 2 IMTs (33%), and 3 SS (30%), and was generally weak and cytoplasmic. Reactivity for podoplanin was more common in spindle cell GISTs (5/13 [38%]) than in epithelioid or mixed-type GISTs (2/16 [13%]). Podoplanin is a highly sensitive marker for FDC tumors and may be useful to help confirm the diagnosis in conjunction with conventional FDC markers, particularly in the differential diagnosis of dendritic cell and histiocytic lesions.     

An inflammatory myofibroblastic tumor in liver with ALK and RANBP2 gene rearrangement: combination of distinct morphologic, immunohistochemical, and genetic features

Inflammatory myofibroblastic tumor is an intermediate-grade neoplasm with potential for recurrence and rare metastasis. Rearrangement of the anaplastic lymphoma kinase gene with variable fusion partners and anaplastic lymphoma kinase expression using immunohistochemistry are noted in about half of the tumors. We present a hepatic inflammatory myofibroblastic tumor from a 34-year–old man with an unusual rearrangement between the Ran binding protein 2 and anaplastic lymphoma kinase genes, as well as a peculiar round cell transformation of tumor cells and a unique nuclear membrane expression of anaplastic lymphoma kinase protein. As the fourth reported inflammatory myofibroblastic tumor with this fusion so far, we find that these genetic and morphologic features may be related to a poor clinical outcome. The diagnostic difficulty and other prognostic factors of inflammatory myofibroblastic tumor are also discussed.     

Plasmablastic lymphomas and plasmablastic plasma cell myelomas have nearly identical immunophenotypic profiles.

Plasmablastic lymphoma is an aggressive neoplasm that shares many cytomorphologic and immunophenotypic features with plasmablastic plasma cell myeloma. However, plasmablastic lymphoma is listed in the World Health Organization (WHO) classification as a variant of diffuse large B-cell lymphoma. To characterize the relationship between plasmablastic lymphoma and plasmablastic plasma cell myeloma, we performed immunohistochemistry using a large panel of B-cell and plasma cell markers on nine cases of plasmablastic lymphoma and seven cases of plasmablastic plasma cell myeloma with and without HIV/AIDS. The expression profiles of the tumor suppressor genes p53, p16, and p27, and the presence of Epstein-Barr virus (EBV) and human herpes virus type 8 (HHV-8) were also analyzed. All cases of plasmablastic lymphoma and plasmablastic plasma cell myeloma were positive for MUM1/IRF4, CD138, and CD38, and negative for CD20, corresponding to a plasma cell immunophenotype. PAX-5 and BCL-6 were weakly positive in 2/9 and 1/5 plasmablastic lymphomas, and negative in all plasmablastic plasma cell myelomas. Three markers that are often aberrantly expressed in cases of plasma cell myelomas, CD56, CD4 and CD10, were positive in 5/9, 2/5, and 6/9 plasmablastic lymphomas, and in 3/7, 1/5, and 2/7 plasmablastic plasma cell myelomas. A high Ki-67 proliferation index, overexpression of p53, and loss of expression of p16 and p27 were present in both tumors. No evidence of HHV-8 infection was detected in either neoplasm. The only significant difference between plasmablastic lymphoma and plasma cell myeloma was the presence of EBV-encoded RNA, which was positive in all plasmablastic lymphoma cases tested and negative in all plasma cell myelomas. In conclusion, most cases of AIDS-related plasmablastic lymphoma have an immunophenotype and tumor suppressor gene expression profile virtually identical to plasmablastic plasma cell myeloma, and unlike diffuse large B-cell lymphoma. These results do not support the suggestion in the WHO classification that plasmablastic lymphoma is a variant of diffuse large B-cell lymphoma.     

Synchronous primary gastric mantle cell lymphoma and early gastric carcinoma: a case report

Mantle cell lymphoma (MCL) commonly invades the gastrointestinal (GI) tract. However, primary GI MCL is rare. We experienced a case of synchronous early gastric cancer (EGC) with primary gastric MCL found as a single early lesion rather than as multiple lymphomatous polyposis.

An EGC was found in the cardia of a 64-year-old male on a routine GI endoscopic examination. A specimen obtained by total gastrectomy revealed another slightly elevated lesion in the pylorus. Microscopically, monotonous small- to medium-sized atypical lymphocytes with angulated nuclei formed a mass beneath the gastric mucosa. On immunohistochemical staining, the tumor cells revealed strong positivity for cyclin D1, positivity for both CD20 and bcl-2, and weak positivity for CD5, suggesting MCL. Clinically, there was no lymphoma in any other part of the body.

This is the first case of an EGC accompanying a primary gastric MCL. Further investigation of a relationship between MCL and EGC and of factors that may affect GI involvement of MCL is necessary.