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.

Pathogenetic and diagnostic significance of microRNA deregulation in peripheral T-cell lymphoma not otherwise specified.

Peripheral T-cell lymphomas not otherwise specified (PTCLs/NOS) are rare and aggressive tumours whose molecular pathogenesis and diagnosis are still challenging. The microRNA (miRNA) profile of 23 PTCLs/NOS was generated and compared with that of normal T-lymphocytes (CD4+, CD8+, naive, activated). The differentially expressed miRNA signature was compared with the gene expression profile (GEP) of the same neoplasms. The obtained gene patterns were tested in an independent cohort of PTCLs/NOS. The miRNA profile of PTCLs/NOS then was compared with that of 10 angioimmunoblastic T-cell lymphomas (AITLs), 6 anaplastic large-cell lymphomas (ALCLs)/ALK+ and 6 ALCLs/ALK-. Differentially expressed miRNAs were validated in an independent set of 20 PTCLs/NOS, 20 AITLs, 19 ALCLs/ALK- and 15 ALCLs/ALK+. Two hundred and thirty-six miRNAs were found to differentiate PTCLs/NOS from activated T-lymphocytes. To assess which miRNAs impacted on GEP, a multistep analysis was performed, which identified all miRNAs inversely correlated to different potential target genes. One of the most discriminant miRNAs was selected and its expression was found to affect the global GEP of the tumours. Moreover, two sets of miRNAs were identified distinguishing PTCL/NOS from AITL and ALCL/ALK-, respectively. The diagnostic accuracy of this tool was very high (83.54%) and its prognostic value validated.

Unusual presentation of sarcoid-like reaction on bone marrow level associated with mediastinal lymphadenopathy on (18)F-FDG-PET/CT resembling an early recurrence of Hodgkin's Lymphoma.

(18)F-FDG-PET/CT is widely employed to evaluate lymphoma patients. False positive results are quite frequent, generally due to active phase of inflammation. We describe an unusual PET/CT presentation of a sarcoid-like reaction (SLR) in a patient monitored for Hodgkin Lymphoma characterized by an intense uptake in lymph nodes and multiple bone foci in a PET/CT study. The final diagnosis was obtained by biopsy. This study draws attention to the fact that multifocal bone marrow uptakes due to a sarcoideal reaction may be a possible cause of false positive results in (18)F-FDG-PET/CT studies in oncology patients.

Proliferation centers in chronic lymphocytic leukemia: correlation with cytogenetic and clinicobiological features in consecutive patients analyzed on tissue microarrays.

To better define the significance of proliferation centers (PCs), the morphological hallmark of chronic lymphocytic leukemia (CLL), lymph node biopsies taken from 183 patients were submitted to histopathologic and fluorescence in situ hybridization (FISH) studies using a 5-probe panel on tissue microarrays. Seventy-five cases (40.9%) with confluent PCs were classified as 'PCs-rich' and 108 cases (59.1%) with scattered PCs were classified as 'typical'. Complete FISH data were obtained in 101 cases (55.1%), 79 of which (78.2%) displayed at least one chromosomal aberration. The incidence of each aberration was: 13q- 36,7%, 14q32 translocations 30.8%, 11q- 24.7%, trisomy 12 19.5% and 17p- 15.6%. Five cases showed extra copies of the 14q32 region. The 'PCs-rich' group was associated with 17p-, 14q32/IgH translocation, +12, Ki-67>30%. The median survival from the time of tissue biopsy for PCs-rich and typical groups was 11 and 64 months, respectively (P=0.00001). The PCs-rich pattern was the only predictive factor of an inferior survival at multivariate analysis (P=0.022). These findings establish an association between cytogenetic profile and the amount of PC in CLL, and show that this histopathologic characteristic is of value for risk assessment in patients with clinically significant adenopathy.

Partial nodal involvement by marginal zone lymphoma. Use of IGK gene rearrangement analysis in diagnostic work-up.

Nodal marginal zone lymphoma (NMZL) is an indolent B-cell lymphoma that originates from the marginal zone of B-cell follicles. The tumour is rather uncommon, and shares some morphologic and immunophenotypic similarities with the extranodal form of marginal zone lymphomas. However, diagnosis of NMZL implies the exclusion of lymphoplasmacytic lymphoma, follicular lymphoma, and lymph node involvement by extra nodal or splenic marginal zone B-cell lymphoma In addition, its distinction from reactive conditions, including T-zone hyperplasia, are sometimes problematic based on morphologic grounds. We describe a patient who presented with cervical and inguinal lymphadenopathies and high inflammation indexes. Bone marrow and lymph node biopsies were performed for definitive diagnosis. Bone marrow histological and immunophenotypic examinations were normal and excluded haematological disease. In contrast, lymph node evaluation showed some features compatible with a possible lymphoproliferative disorder, even though no definite diagnosis could be made based on morphologic and immunohistochemical investigation. In particular, the problem of a differential diagnosis between NMZL and a florid hyperplasia of monocytoid B-elements was posed. Thus, in order to assess the nature (neoplastic vs. reactive) of the lesion, molecular analysis of the immunoglobulin genes was performed by PCR. Notably, although no clonal rearrangements were revealed by IGHV@ analysis, further evaluation of the immunoglobulin light chain (IGKV@) confirmed the presence of a clonal B-cell population. Accordingly, a final diagnosis of NMZL was made. In conclusion, this case is a good example of the crucial role of complete molecular analysis in the diagnostic work up of lymphoproliferative disorders.

Langerhans cell histiocytosis: bilateral temporal bone involvement in an adult with diabetes insipidus.

OBJECTIVE: To present a clinical case of an adult affected by Langerhans cell histiocytosis with bilateral, non-simultaneous, involvement of the temporal bone, associated with diabetes insipidus and to review the literature. METHODOLOGY: A rare case of bilateral temporal bone involvement of Langerhans cell histiocytosis in a 42-year-old woman affected by diabetes insipidus is reported. We present patient's clinical history supported by radiologic, histopathologic and audiologic findings. RESULTS: The patient was submitted to a series of otologic surgical procedures due to the progression of the disease. Ossicular chain was always preserved, so that conservative surgery (canal wall-up technique) was performed, permitting the achievement of good hearing results, bilaterally. CONCLUSIONS: Temporal bone involvement of Langerhans cell histiocytosis may lead to a progressive chronic disease. However, the ossicular chain can remain uninvolved, making a conservative surgical treatment possible. Careful follow-up is essential for detecting new lesions and serial CT scans are mandatory.

Primary Cutaneous Large B-Cell Lymphoma, Leg Type, Localized on the Dorsum.

Primary cutaneous large B-cell lymphoma, leg-type (PCLBCL-LT), is a large B-cell lymphoma primarily involving the skin. It is distinguished from the other 3 subsets of this lymphoproliferative disorder by its immunohistopathological features, configuring confluent sheets of medium-sized to large B lymphocytes with round nuclei provided with evident nucleoli, resembling centroblasts or immunoblasts, which express Bcl-6, Bcl-2. Prevalently appearing on the lower limbs, as a single or multicentric and frequently ulcerated skin nodule or plaque, PCLBCL-LT has a worse prognosis than the other large B-cell lymphomas. Moreover, the age of onset is delayed (7th decade) compared to those of the other 3 subtypes (6th decade); it presents a slight female predominance (2:1), and a higher percentage of positivity to Bcl-2. We present a 52-year-old man who showed a 2-year standing, non-ulcerated, round, 4 cm in diameter, red plaque, medially located on the dorsum. After biopsy the diagnosis of PCLBCL-LT was made on histopathological and immunohistochemical studies, the latter showing positivity to CD20, Bcl-2, and Bcl-6. After treatment with radiotherapy the patient has shown a 4.4-year follow-up free of disease.

Unusual inflammatory and hyperkeratotic halo naevus in children.

Although the classic halo naevus (HN) is a melanocytic naevus with a surrounding rim of depigmentation, these naevi can present unusual features. We describe an unusual and previously unreported variety of HN in children. Between March 1999 and September 2002, 14 children (11 boys and three girls, age range 6-14 years) were referred to us for evaluation of one or more 'inflamed' naevi. All the affected naevi showed the same clinical development: (i) after an initial inflammatory stage their surfaces gradually became thickened and rough, then (ii) verrucous and raised, and finally (iii) scaly crusted. A marked halo of depigmentation subsequently developed in all lesions, with simultaneous disappearance of the hyperkeratotic surface appearance. Lesions were multiple in five cases and single in nine, and were mainly located on the back (nine cases). Excisional biopsy was performed in eight cases. The biopsies were all taken in the 'prehalo phase'. In each case, histopathology revealed a compound melanocytic naevus, with additional features that varied depending on the clinical stage of the lesion. Immunohistochemical staining of the dense inflammatory infiltrate showed a predominance of CD3(+)/CD8(+) T lymphocytes, as usually occurs in HN. On the basis of these observations, we believe that the described naevi represent an unusual variety of HN in children. Knowledge of this possible clinical evolution of HN is important to avoid unnecessary surgical excision in these young patients.

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.

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.

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.