Correction to: A practical algorithmic approach to mature aggressive B cell lymphoma diagnosis in the double/triple hit era: selecting cases, matching clinical benefit.

The first and family names of the authors were interchanged and are now presented correctly. The original article has been corrected.

A practical algorithmic approach to mature aggressive B cell lymphoma diagnosis in the double/triple hit era: selecting cases, matching clinical benefit : A position paper from the Italian Group of Haematopathology (G.I.E.).

An accurate diagnosis of clinically distinct subgroups of aggressive mature B cell lymphomas is crucial for the choice of proper treatment. Presently, precise recognition of these disorders relies on the combination of morphological, immunophenotypical, and cytogenetic/molecular features. The diagnostic workup in such situations implies the application of costly and time-consuming analyses, which are not always required, since an intensified treatment option is reasonably reserved to fit patients. The Italian Group of Haematopathology proposes herein a practical algorithm for the diagnosis of aggressive mature B cell lymphomas based on a stepwise approach, aimed to select cases deserving molecular analysis, in order to optimize time and resources still assuring the optimal management for any patient.

Central nervous system tissue heterotopia of the nose: case report and review of the literature.

The authors present a case of heterotopic central nervous system tissue observed in an 81-year-old male in the form of an ethmoidal polyp. A review of the literature indicates that this is a rare condition characterised by a connective tissue lesion with astrocytic and oligodendrocytic glial cells, which may be located outside the nasal pyramid in some cases and inside the nasal cavity in others. The most important diagnostic aspect involves differentiating these from meningoencephalocele, which maintains an anatomical connection with central nervous system tissue. Contrast-enhanced imaging is essential for diagnosis, as in cases of heterotopic central nervous system tissue, it will demonstrate that there are no connections with intra-cranial tissue. Endoscopic excision is the treatment of choice.

Thymoma arising in the wall of a thymic cyst.

A 54-year-old male, non smoker, began to suffer from persistent dyspnoea and fever. X-ray and CT scan showed a cystic lesion located in the left anterior mediastinum. This lesion was removed instead of the initially scheduled surgical resection with video-assisted thoracoscopic surgery (VATS) preceded by fine needle aspiration (FNA). A diagnosis of thymoma arising in the wall of thymic cyst was made. Such a rare tumour should be taken into consideration in treating patients with a cystic mediastinal lesion, before VATS and FNA.

Myeloid sarcoma: clinico-pathologic, phenotypic and cytogenetic analysis of 92 adult patients.

Myeloid sarcoma (MS) is a rare neoplasm whose knowledge is largely based on case reports and/or technically dated contributions. Ninety-two MSs in adulthood with clinical data available were evaluated both morphologically and immunohistochemically. Seventy-four cases were also studied by fluorescent in situ hybridization on tissue sections and/or conventional karyotyping on bone marrow or peripheral blood. Histologically, 50% of the tumors were of the blastic type, 43.5% either monoblastic or myelomonocytic and 6.5% corresponded to different histotypes. CD68/KP1 was the most commonly expressed marker (100%), followed by myeloperoxidase (83.6%), CD117 (80.4%), CD99 (54.3%), CD68/PG-M1 (51%), CD34 (43.4%), terminal-deoxy-nucleotidyl-transferase (31.5%), CD56 (13%), CD61/linker for activation of T cells (2.2%), CD30 (2.2%) and CD4 (1.1%). Foci of plasmacytoid monocyte differentiation were observed in intestinal cases carrying inv16. Chromosomal aberrations were detected in about 54% of cases: monosomy 7(10.8%), trisomy 8(10.4%) and mixed lineage leukemia-splitting (8.5%) were the commonest abnormalities, whereas t(8;21) was rare (2.2%). The behavior was dramatic irrespective of presentation, age, sex, phenotype and cytogenetics. Most if not all, long survivors received bone-marrow transplantation. The present report expands the spectrum of our knowledge showing that MS has frequent monoblastic/myelomonocytic differentiation, displays distinctive phenotypic profile, carries chromosomal aberrations other than t(8;21), and requires supra-maximal therapy.

CD27 distinguishes two phases in bone marrow infiltration of splenic marginal zone lymphoma.

AIMS: To investigate CD27 expression in splenic marginal zone lymphoma (SMZL), an indolent low-grade B-cell lymphoma with constant involvement of the bone marrow, especially with an intrasinusoidal pattern. It is not clear if the neoplastic clone is composed of virgin or somatically mutated B cells. CD27 is reported to be a hallmark of memory B cells. METHODS AND RESULTS: We evaluated 64 bone marrow biopsy specimens (BMBs) from 36 patients with SMZL for the expression of CD27. For comparison, splenectomy specimens of patients with traumatic splenic rupture or with SMZL were used. All BMBs showed lymphomatous infiltration. When located in the marrow sinusoids, neoplastic cells were CD27- in all cases and therefore corresponded to naive B cells. In nodular/interstitial infiltration, the cells were CD27+ and therefore corresponded to memory B cells. No difference in immunohistochemical expression of B and T antibodies was found between intrasinusoidal and interstitial/nodular infiltration. CD27 was constantly expressed in the splenic marginal zone of normal spleen, surgically removed for trauma, and in seven out of 10 spleens with SMZL. CONCLUSION: We propose the existence of two different phases of neoplastic progression with, first, expansion of a virgin B clone in the bone marrow and, following exposure to antigen, a re-colonization of the bone marrow.

Clear-cell proliferation of the lung with lymphangioleiomyomatosis-like change.

AIMS: To describe two cases of a peculiar pulmonary lesion, which expand both the morphological and the immunophenotypic spectrum of perivascular epithelioid cell (PEC)-related disorders. METHODS AND RESULTS: One man and one female, with and without the tuberous sclerosis complex (TSC), respectively, showed pulmonary cysts and small nodules on computed tomography scan. In the former, lymphangioleiomyomatosis (LAM) was suspected. In both cases, an open lung biopsy was performed, whose cut surface displayed numerous cysts lined by thin/thick septa. Microscopically, the septa were associated with micronodular or interstitial proliferation of medium/large-sized elements with abundant clear (periodic acid-Schiff-positive/diastase-sensitive) cytoplasm and distinct cell borders, embedded in fibrous tissue. The elements were CD34+, vimentin-positive and, to a lesser extent, HMB-45+ and MART-1+. The stains for specific muscle actin, desmin, S100 protein, CD31, FVIIIRAg, cytokeratins, CD45, CD68, oestrogen and progesterone receptors were all negative. Ki67 labelling was <1%. Electron microscopy displayed cytoplasmic vacuoles containing glycogen particles. The TSC1 and TSC2 gene status could not be assessed because of poor DNA preservation. In the man with TSC, a focus of micronodular pneumocyte hyperplasia was also found. CONCLUSIONS: Because of the coexpression of CD34 and melanoma-associated antigens and the occurrence of TSC in one patient, the cases described here add a new piece to the puzzle of PEC lesions and contribute to the open discussion on the origin of LAM and LAM-like proliferations.

Prognostic significance of CD44 expression in diffuse large B cell lymphoma of activated and germinal centre B cell-like types: a tissue microarray analysis of 90 cases.

BACKGROUND: Gene expression profiling of diffuse large B cell lymphoma (DLBCL) revealed three disease types: germinal centre B cell-like (GC), activated B cell-like (ABC), and a "third" type. Expression of CD44 variant isoforms (CD44v) is associated with an unfavourable clinical outcome in DLBCL, but previous studies did not consider the clinicopathological heterogeneity of this disease. AIMS: To analyse the expression and prognostic significance of CD44 in DLBCL types. METHODS: A tissue microarray (TMA) comprising 90 DLBCLs was constructed. CD10, CD20, bcl-2, bcl-6, CD44 standard isoform (CD44s), and CD44v4, CD44v6, and CD44v9 were analysed immunohistochemically and correlated with clinical follow up. RESULTS: TMA expression of CD10, CD20, bcl-2, and bcl-6 showed 100% concordance with results from conventional sections in 60 cases. Samples were segregated into 22 GC (bcl-6+/CD10+/bcl-2-), 25 ABC (bcl-6-/CD10-/bcl-2+), and 35 unclassifiable DLBCLs. Overall survival (OS) at 30 months was 89%, 44%, and 58% in GC, ABC, and unclassified types, respectively. CD44v6 was coexpressed with bcl-2, appeared predominantly on bcl-6 negative cases, and correlated with disease stage. Cases negative for CD44s could be separated into CD44v6 negative (OS, 82% at 70 months) and CD44v6 positive (OS, 58%). CONCLUSIONS: TMA technology is useful for immunophenotyping and clinicopathological analysis of large lymphoma populations. The GC phenotype of DLBCL is of independent prognostic significance for OS. Expression of CD44v6 correlates with disease stage, and might contribute to lymphoma dissemination. CD44v6 is expressed predominantly in ABC DLBCL, and in CD44 negative cases is associated with worse OS.

Diffuse large B-cell lymphoma: one or more entities? Present controversies and possible tools for its subclassification.

Diffuse large B-cell lymphoma (DLBCL) is the commonest type of lymphoid tumour world-wide. This category was included both in the REAL and WHO Classification aiming to lump together all malignant lymphomas characterized by the large size of the neoplastic cells, B-cell derivation, aggressive clinical presentation, and the need for highly effective chemotherapy regimens. These tumours are detected as primary or secondary forms both at the nodal and extranodal levels, in immunocompetent hosts as well as in patients with different types of immunosuppression. They display a significant variability in terms of cell morphology and clinical findings, which justifies the identification of variants and subtypes. Among the latter, the primary mediastinal one does actually correspond to a distinct clinicopathological entity. Immunophenotypic, tissue microarray and molecular studies underline the extreme heterogeneity of DLBCLs and suggest a subclassification of the tumour, based on the identification of different pathogenic pathways, which might have much greater relevance than pure morphology for precise prognostic previsions and adoption of ad hoc therapies. The more recent acquisitions on the pathobiology of DLBCLs are reviewed in the light of the authors' experience, aiming to contribute to the existing debate on the topic.

Clinical efficacy and antiangiogenic activity of thalidomide in myelofibrosis with myeloid metaplasia. A pilot study.

Increased neoangiogenesis has been reported in myelofibrosis with myeloid metaplasia (MMM). Thus we studied the effects of thalidomide, an antiangiogenic drug, in 12 MMM patients. Before treatment, all the cases showed a significantly increased micro-vessel density (MVD); in all eight tested cases bFGF and VEGF plasma levels were higher than controls. All patients presented disease progression in the last 3 months with standard therapy, regarding splenomegaly, anemia and/or thrombocytopenia and/or hyperleukocytosis. Thalidomide was administered at daily doses increasing from 100 to 600 mg. Eleven out of 12 patients were evaluable. No progression of disease was seen during the treatment in any case. In particular, spleen size decreased in 7/11 patients, anemia improved in 3/4 (two are now transfusion independent), thrombocytopenia in 2/2 and hyperleukocytosis in 2/5 patients. Side-effects were frequent, although not severe. After treatment, VEGF and bFGF plasma levels varied widely and in selected cases decreased. In particular, VEGF and/or bFGF decreased in 4/5 responders and in 1/3 non-responders. Moreover, MVD significantly decreased in all the responders evaluated after treatment. We conclude that thalidomide is a feasible therapy in MMM patients and looks promising at least to control the growth progression of disease.

Primary follicular lymphoma of the testis in childhood: an entity with peculiar clinical and molecular characteristics.

BACKGROUND/AIMS: Paediatric primary follicular lymphoma of the testis (PPFLT) is exceptional: the few reported cases seem to lack BCL-2 gene rearrangement and/or protein expression. The aim of this study was to characterise a PPFLT arising in a 4 year old boy. METHODS: This case was characterised using conventional histological analysis, immunohistochemistry, and a polymerase chain reaction based method for the detection of immunoglobulin V(H) chain rearrangements. RESULTS: The neoplasm was staged I(E)/A; left orchiectomy and chemotherapy were performed, producing complete remission. Histology showed a predominantly follicular lymphoid infiltrate mainly composed of centroblast-like cells. The phenotype was CD20(+), CD79a(+), CD10(+), bcl-6(+), B cell specific activating protein(+), kappa light chain(+), CD30(-/+), interferon regulating factor 4(-/+), c-myc(-/+), lambda light chain(-), CD3(-), bcl-2(-), p53(-), cytokeratin(-), and placental alkaline phosphatase(-). Lymphomatous elements were found within a CD21(+) follicular dendritic cell network and 70% were positive for Ki-67/MIB-1. Molecular analysis revealed monoclonal immunoglobulin heavy chain gene rearrangement and BCL-6 mutations, in the absence of BCL-2 major breakpoint and BCL-2 minor cluster region rearrangements, p53 mutations, and death associated protein kinase gene hypermethylation. CONCLUSIONS: These findings suggest a different pathogenesis of PPTFL compared with adult follicular lymphoma and might explain its favourable course in spite of aggressive histology.

Hodgkin's lymphoma: the pathologist's viewpoint.

Despite its well known histological and clinical features, Hodgkin's lymphoma (HL) has recently been the object of intense research activity, leading to a better understanding of its phenotype, molecular characteristics, histogenesis, and possible mechanisms of lymphomagenesis. There is complete consensus on the B cell derivation of the tumour in most cases, and on the relevance of Epstein-Barr virus infection and defective cytokinesis in at least a proportion of patients. The REAL/WHO classification recognises a basic distinction between lymphocyte predominance HL (LP-HL) and classic HL (CHL), reflecting the differences in clinical presentation and behaviour, morphology, phenotype, and molecular features. CHL has been classified into four subtypes: lymphocyte rich, nodular sclerosing, with mixed cellularity, and lymphocyte depleted. The borders between CHL and anaplastic large cell lymphoma have become sharper, whereas those between LP-HL and T cell rich B cell lymphoma remain ill defined. Treatments adjusted to the pathobiological characteristics of the tumour in at risk patients have been proposed and are on the way to being applied.

Myeloperoxidase expression by histiocytes in Kikuchi's and Kikuchi-like lymphadenopathy.

Forty-five examples of Kikuchi's lymphadenitis (KL), 5 Kikuchi-like lupus erythematosus lymphadenopathies, 25 nonnecrotizing lymphadenitidies (5 toxoplasmic, 5 sarcoid-like, 6 dermatopathic, 4 suppurative, 3 tubercular, 2 with sinus histiocytosis), 4 examples of hyaline-vascular Castleman disease (CD), 2 plasmacytoid monocyte tumors (PM-Ts), and 61 accessory cell neoplasms were studied by a panel of antibodies, including the PG-M1 (against a macrophage-restricted CD68 epitope) and a polyclonal anti-myeloperoxidase (MPO). In KL and Kikuchi-like lupus erythematosus lymphadenopathies, 25 to 75% of CD68(+) histiocytes co-expressed MPO. This did not occur in nonnecrotizing lymphadenitidies and accessory cell neoplasms. MPO(+)/CD68(+) elements corresponded to nonphagocytosing mononuclear cells and some crescentic macrophages and phagocytosing histiocytes. Typical PMs were MPO(-)/CD68(+) in all cases, including CD and PM-T. Our observations suggest that in KL and KL-like lymphadenopathies: 1) MPO(+)/CD68(+) blood monocytes might be attracted into tissues because of the lack or paucity of granulocytes and the need of MPO for oxidative processes; 2) PMs are more likely to be involved in the cytotoxic immune reaction than in phagocytic phenomena; 3) the peculiar phenotype of the histiocytic component can be usefully used for the differentiation from malignant lymphoma and PM-T.

Diffuse large B-cell lymphoma with primary retroperitoneal presentation: clinico-pathologic study of nine cases.

UNLABELLED: Diffuse large B-cell lymphoma primarily presenting in the retroperitoneum (PRLBCL) has been the object of occasional reports, all based on dated techniques. MATERIALS AND METHODS: Nine PRLBCLs--with clinical information and paraffin blocks available--were reviewed on morphologic, immunohistochemical and molecular grounds. RESULTS: At microscopic examination, the cases were characterized by a diffuse proliferation of large cells (CD20+, CD79a+, CD3-), displaying a wide rim of cytoplasm (clear in seven instances and acidophilic in two), associated with sclerosis and frequent compartmentalization. Phenotypic and molecular analyses showed that: a) three cases were bcl-2+, bcl-6+, HLA-DR+, and CD10+ (1/3), with associated follicular dendritic cell (FDC) component and bcl-2 gene rearrangements; b) four cases were bcl-2, bcl-6, HLA-DR, CD10, FDC, and bcl-2 gene rearrangement negative; c) two cases had border-line characteristics (bcl-2+, bcl-6+, FDC+, HLA-DR-, CD10-, and bcl-2 gene rearrangement-). The first subgroup was thought to be of follicular derivation, as was the third due to bcl-6 and FDC stains. Of the corresponding five patients, three are in complete remission and two died of disease within 12 months. No obvious, normal counterpart was detected in the remaining four tumors: the corresponding patients died of disease in 3-23 months. The problem of similarities between PRLBCL and primary mediastinal LBCL is discussed. CONCLUSIONS: Although the present series is small, our findings suggest that PRLBCL may represent a more heterogeneous group of tumors than previously thought, which merits further phenotypic and molecular studies to broaden the understanding of its histogenesis and behavior.