Recommendations for gross examination and sampling of surgical specimens of the spleen

This review examines handling and processing of spleen biopsies and splenectomy specimens with the aim of providing the pathologist with guidance in optimizing examination and diagnosis of splenic disorders. It also offers recommendations as to relevant reporting factors in gross examination, which may guide diagnostic workup. The role of splenic needle biopsies is discussed. The International Spleen Consortium is a group dedicated to promoting education and research on the anatomy, physiology, and pathology of the spleen. In keeping with these goals, we have undertaken to provide guidelines for gross examination, sectioning, and sampling of spleen tissue to optimize diagnosis (Burke). The pathology of the spleen may be complicated in routine practice due to a number of factors. Among these are lack of familiarity with lesions, complex histopathology, mimicry within several types of lesions, and overall rarity. To optimize diagnosis, appropriate handling and processing of splenic tissue are crucial. The importance of complete and accurate clinical history cannot be overstated. In many cases, significant clinical history such as previous lymphoproliferative disorders, hematologic disorders, trauma, etc, can provide important information to guide the evaluation of spleen specimens. Clinical information helps plan for appropriate processing of the spleen specimen. The pathologist should encourage surgical colleagues, who typically provide the specimens, to include as much clinical information as possible.

Epstein-Barr virus (EBV)-associated lymphoid lesions of the head and neck

Epstein Barr virus (EBV)-related lymphoproliferative processes occur in the head and neck ranging from reactive processes such as infectious mononucleosis to high grade malignant lymphomas. EBV is a ubiquitous herpes virus that infects more than 90% of adults worldwide, and is generally transferred though saliva. Primary infection can occur throughout life. EBV is the first virus linked to malignancies, both epithelial and lymphoid. Both T and B cell lymphomas can be associated with EBV and evidence shows that an individual's response to the acute EBV infection may be critical in the development of subsequent lymphoma. Currently, in situ hybridization for EBER is the most sensitive available test to detect EBV and should be routinely performed in lymphoproliferative lesions of the head and neck. Immunohistochemistry for EBV related proteins, such as LMP1, is much less sensitive than EBER in situ hybridization, but can help determine latency patterns of EBV infection. Although relatively rare, primary EBV-related lymphomas must be considered in the differential of atypical lymphoid proliferations in the head and neck. We present selected EBV-related disorders of the head and neck discussing etiology as well as differential diagnosis.

Practical Applications in Immunohistochemistry: Evaluation of Diffuse Large B-Cell Lymphoma and Related Large B-Cell Lymphomas

Context

Diffuse large B-cell lymphoma is the most commonly diagnosed subtype of lymphoma worldwide. The current World Health Organization (WHO) classification includes several subtypes, based on a combination of clinical, immunohistochemical, and genetic differences. Immunohistochemical staining is essential in evaluating diffuse large B-cell lymphoma and many related large B-cell lymphomas and aggressive B-cell lymphomas.

Objective

To address different immunohistochemical features used for identification, subclassification, prognosis and in some cases, therapy, of diffuse large B-cell lymphoma and related lymphomas.

Data Sources

The information outlined in this review article is based on our experiences with routine cases, on the current WHO classification of hematopoietic and lymphoid tumors, and on a review of English-language articles published throughout 2014.

Conclusions

Features and diagnostic criteria of diffuse large B-cell lymphoma, aggressive variants of B-cell lymphomas, including Burkitt lymphoma and “double-hit” lymphomas, are discussed. Identification of cell of origin (germinal center type versus activated B-cell type) is discussed at length. Finally, practical approaches for diagnosis are discussed.

The t(14;18)(q32;q21)/IGH-MALT1 translocation in gastrointestinal extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma)

AIMS

Studies have indicated that the t(14;18)(q32;q21)/IGH-MALT1 translocation is present in extranodal marginal zone lymphomas of mucosa-associated lymphoid tissue (MALT lymphoma). However, only a few studies have investigated the incidence of t(14;18)/IGH-MALT1 in primary gastrointestinal MALT lymphomas or in diffuse large B-cell lymphomas (DLBCL). The overall significance of t(14;18)/IGH-MALT1 in gastrointestinal MALT lymphomas is not clear. We examined 41 gastrointestinal MALT lymphoma and 23 DLBCL cases, with the aim of further understanding the role of t(14;18)/IGH-MALT1 in these diseases.

METHODS AND RESULTS

Fluorescence in-situ hybridization (FISH) assays for the detection of t(14;18)/IGH-MALT1 and t(11;18)(q21;q21)/API2-MALT1, along with immunostaining and histological evaluations, were performed on selected cases. Of the 64 analysed cases, one gastric MALT lymphoma and one colonic MALT lymphoma were positive for t(14;18)/IGH-MALT1.

CONCLUSIONS

We describe what are, to our knowledge, the first reported primary colonic MALT lymphoma carrying t(14;18)(q32;q21)/IGH-MALT1, and one of the few reported cases of gastric MALT lymphoma with this translocation. As this translocation is seen in only a few gastrointestinal MALT lymphomas, it is not useful as a diagnostic marker for routine clinical services. Although these findings suggest that t(14;18)/IGH-MALT1 is a rare molecular event in gastrointestinal MALT lymphomas and DLBCLs, further studies to elucidate the role of this genetic alteration in these diseases are indicated.

Abstract 3609: Generation and characterization of a novel monoclonal antibody recognizing both the blood and tissue form of human PCBP-1

Background: Poly(rC)-binding protein-1 (PCBP-1) is a nucleic-acid-binding protein that localizes in nucleus and/or cytoplasm of cells. Shuttling between nucleus and cytoplasm has been related to its function in regulation of RNA transcription, translation and also implicated its involvement in cancer metastasis, progression and chemoresistance. In the present study, we investigated the levels and expression of PCBP-1 in breast carcinoma and its potential use as a biomarker in breast carcinoma differential diagnosis. Methods/Results: We generated a novel monoclonal antibody (mAb), AB-PCBP-1 using hybridoma technology and native protein in cell culture medium as immunogen. This mAb is of IgG1 (kappa) type. It specifically recognized both native and denatured human PCBP-1 protein and displayed high affinity as assessed by ELISA, immunohistochemistry assay, western blot and flow cytometry applications. Using this mAb in competitive ELISA, we showed for the first time that soluble PCBP-1 level is significantly increased in the plasma of metastatic breast cancer patients’ plasma. PCBP-1 is also expressed in metastatic breast carcinoma tissue by immunohistochemistry. Seventy percent of normal breast ducts and lobules expressed strong nuclear staining whereas cytoplasmic staining was less specific and found in most cancer tissues. We examined 90 cases of breast carcinoma tissues classified as either ductal and lobular carcinoma. To evaluate the immunoreactivity of PCBP-1, the staining intensity and intracellular distribution were compared and scored as 0, 1+, 2+ and 3+ based on intensity. Seventy nine % (60 out of 76) of ductal carcinomas showed strong cytoplasmic staining (2+ and 3+) and 45% also exhibited strong nuclear localization for PCBP-1. Lobular carcinomas (n=14), on the other hand, showed an exclusively nuclear staining pattern.Conclusion: AB-PCBP-1 mAb showed high performance in blood and tissue assays. PCBP-1 levels were significantly increased in blood and demonstrated a distinct pattern of expression related to histological tumor types, suggesting that PCBP-1 may be involved in a regulatory mechanism that differs in various subtypes of breast carcinoma. The results suggest the potential clinical use of PCBP-1 as a therapeutic target and/or a biomarker in blood and tissue for the diagnosis and prognosis of breast carcinoma.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3609. doi:1538-7445.AM2012-3609

Clear Cell Tumors of Soft Tissue

Clear cell lesions of soft tissue include varying morphologic patterns and a range of clinical behaviors and prognoses. Benign lesions include perivascular epithelioid cell tumors, clear cell fibrous papule, and distinctive dermal clear cell mesenchymal tumor; malignant tumors include clear cell sarcoma, liposarcoma, and rare malignant perivascular epithelioid cell tumors. Clear cell variants of other benign and malignant soft tissue tumors include fibrous histiocytoma, atypical fibroxanthoma, myoepithelioma, leiomyoma and leiomyosarcoma, and rhabdomyosarcoma. Metastatic clear cell tumors, including renal cell carcinoma and adrenal cortical carcinoma, should be considered in the differential diagnosis and excluded through clinical history, imaging studies, and immunohistochemical stains.

Activation-induced cytidine deaminase expression in diffuse large B-cell lymphoma with a paracortical growth pattern: a lymphoma of possible interfollicular large B-cell origin

CONTEXT

Activation-induced cytidine deaminase, necessary for immunoglobulin somatic hypermutation and class switch recombination, is usually expressed within the follicular dendritic network but is also expressed in a population of interfollicular large B cells outside the germinal center.

OBJECTIVE

To report 7 cases of diffuse large B-cell lymphoma with a distinct paracortical distribution. Expression of activation-induced cytidine deaminase, previously described in interfollicular large B cells, was evaluated.

DESIGN

A panel of immunohistochemical markers, including double staining for activation-induced cytidine deaminase and CD20, was used to illustrate the cases. Molecular studies were performed by polymerase chain reaction in the paraffin-embedded tissue for t(14;18) chromosomal translocation and immunoglobulin heavy chain and T-cell receptor rearrangements.

RESULTS

Patients included 3 males and 4 females ranging in age from 11 to 59 years (mean, 39 years). All specimens were lymph nodes (4 from the groin, 2 from the neck, and 1 from the axilla). Malignant lymphocytes were positive for CD20 and negative for CD5 and CD10. Staining for CD30, CD43, and BCL-2 was variable. The malignant cells showed at least focal staining with activation-induced cytidine deaminase. All cases were found to be monoclonal by immunoglobulin heavy-chain gene rearrangement or showed light-chain restriction. None of the tested cases showed t(14;18).

CONCLUSIONS

Diffuse large B-cell lymphoma with a paracortical distribution is unusual and may be a distinct morphologic variant. More study is necessary to determine the stage of B-cell development and the cell of origin of these tumors. However, activation-induced cytidine deaminase expression suggests they may arise from a putative interfollicular large B cell.

Sporadic cutaneous angiosarcomas generally lack hypoxia-inducible factor 1alpha: a histologic and immunohistochemical study of 45 cases

Cutaneous angiosarcoma (AS) is a rare malignant neoplasm of dermis composed of infiltrating cells of endothelial phenotype with overall poor prognosis. Although autocrine stimulation by vascular endothelial growth factor secretion may play a role in the pathogenesis of angiosarcoma, its mechanism has not been fully established. Hypoxia-inducible factor-1 (HIF-1) is a transcription factor that mediates cellular and systemic homeostatic responses to hypoxia.. The stability of HIF can regulate key proteins in angiogenesis and the alpha-subunit has been found in epithelial tumors, only 1 case of human retroperitoneal angiosarcoma, and rare vascular proliferations and tumors in knockout mice. We wanted to observe the utility of HIF-1alpha as a marker or explanatory factor in AS. Cases coded as "angiosarcoma" of dermis were culled and re-reviewed for inclusion as AS, based on patient folder, slides, and obtained immunohistochemistry including CD31 and smooth muscle actin (SMA). Hypoxia-inducible factor-1alpha was performed on a subset of cases, with additional available material. Forty-five cases met the criteria for AS; there were 17% females and 83% males, with a mean age at presentation of 67 years (range, 27-88 years). Tumors presented most commonly in the skin of the scalp followed by the left lower leg, face, nose, lower arm, neck, thigh, eyelid, ear, and temple. Associated basal cell carcinoma was noted in 1 patient; no others had other neoplasms or unrelated surgeries. There was no history of other primary, lymphedema, radiation, breast-associated, or thorotrast-induced angiosarcoma. The tumors ranged in size from 0.4 up to 9.5 cm, with a mean size of 2.4 cm. Histopathologically, most tumors were vasoformative, with either solid architecture (n = 35) or papillary endothelial hyperplasia-like foci (n = 7). All cases demonstrated infiltrative growth pattern, cytologic atypia, and mitotic activity, including atypical forms. Surface ulceration was present in 44% and solar elastosis in the most evaluable cases. Epithelioid morphology was present in 29% (n = 13) cases. Mild to moderate lymphocytic inflammatory response was noted in 62% (n = 28) cases. CD31 highlighted malignant endothelial cells. SMA (for pericytes) was generally absent. Hypoxia-inducible factor 1alpha was focally positive in cytoplasm of 3 of 18 (17%) cases studied. Treatment and follow-up data were only available on 4 cases: 2 died of disease within 4 years, 2 others had known recurrence within 2 years. Cutaneous angiosarcoma is largely found on the scalp of older individuals. Requirement for diagnosis includes extravascular proliferation of atypical endothelial cells with mitotic activity in vasoformative, solid, and papillary patterns. Absence of SMA can prove extravascular extension of tumor, outside their normal vessel confines. Cutaneous angiosarcoma generally lacks HIF-1alpha expression. Accordingly, the hypoxic response pathway is not thought to be a documentable common mechanism of angiogenesis in this entity.

Failure to detect active virus replication in mast cells at various tissue sites of HIV patients by immunohistochemistry

A recent report postulated that the mast cell population is a significant reservoir for persistent HIV infection. Our study attempted to validate this hypothesis by quantitatively comparing the distribution of mast cells and cells expressing the HIV protein p24 in HIV infected patients. Consecutive sections of paraffin-embedded human tissues from various tissue sites were subjected to immunohistochemistry with monoclonal antibodies to mast cell tryptase, viral protein p24, and other molecules. The sub-cellular distribution of these molecules was examined, to determine whether immunoreactivities to these molecules would be co-localized within the same cells. Our study revealed that, in two immediate adjacent sections immunostained for mast cell tryptase and p24, respectively, all or nearly all tryptase and p24 expressing cells were distributed at different areas. In the single section double immunostained for mast cell tryptase and p24, 5 (1.1%) of 460 large p24 expressing cell clusters encountered showed a single or few mast cells within or adjacent to p24 expressing cell clusters, but no distinct co-localization of these two proteins was observed. Similarly, no distinct co-localization was observed in any of over 500 isolated individual mast cells and p24 expressing cells. In contrast, macrophages were consistently intermixed with or adjacent to p24 expressing cells, and p24 immunostaining were seen in the cytoplasm of a subset of macrophages. These findings suggest that tissue mast cells do not show evidence for active virus replication by the techniques employed.

Acral myxoinflammatory fibroblastic sarcoma: case series and immunohistochemical analysis

BACKGROUND

Acral myxoinflammatory fibroblastic sarcoma (AMFS) is a rare, low-grade neoplasm most often occurring on the extremities of adults. It consists of mixed inflammatory infiltrates with nodules of epithelioid, spindled and bizarre-appearing cells within a fibrosclerotic-to-myxoid stroma. AMFS frequently recurs, but only rarely metastasizes.

MATERIALS AND METHODS

A retrospective analysis of all cases of AMFS seen in the past 4 years from the Stanford University Laboratory of Surgical Pathology and collaborating institutions was performed. We sought to better characterize the clinicopathologic characteristics of this rare tumor. Immunohistochemical stains, including CD34, epithelial membrane antigen (EMA), epidermal growth factor receptor (EGFR), CD117, CD163, Ki67 and p53, were also performed.

RESULTS

Eighteen cases were analyzed, and clinical information was available on 13 of them. The mean age at diagnosis was 48 years old, 10/13 (77%) occurred on the distal extremities and diameter of the lesions ranged from 1.0 to 10.0 cm. Treatment included wide local or radical excision and local recurrences were not reported. Many of the lesions were multinodular. Histologic characteristics included the presence of fibrosclerotic and myxoid stroma, sheets of spindled to round epithelioid cells, Reed-Sternberg or virocyte-like cells, lipoblast-like cells and rare mitotic figures. In most cases, CD34, EGFR and CD163 were diffusely positive. EMA and CD117 were weakly positive in some cases. Ki67 labeled < 10% of cells, and staining with P53 was variable.

CONCLUSIONS

Because AMFS may be mistaken for lymphoma, infection or tumors with higher metastatic potential, correct diagnosis is important to avoid unnecessary procedures and allow for proper clinical management. EGFR positivity suggests possible therapeutic use in aggressive cases.

Angiolymphoid hyperplasia with eosinophilia developing in a patient with history of peripheral T-cell lymphoma: evidence for multicentric T-cell lymphoproliferative process

BACKGROUND

Angiolymphoid hyperplasia with eosinophilia (ALHE) is a vasocentric process characterized by infiltrates of lymphocytes and eosinophils, usually affecting the muscular arteries of the head and neck. Currently it is unclear whether it is a reactive or neoplastic process.

REPORT

We present a 61-year-old African American male with a twenty year history of superficial skin patches involving the head and neck region. An excisional biopsy of a right submental lymph node revealed an atypical T-cell lymphocytic process, diagnosed as peripheral T-cell lymphoma after immunophenotyping and molecular studies. Three months later the patient underwent a biopsy of a left temporal nodule that was diagnosed as ALHE. Subsequently, at two year follow-up, the patient was diagnosed with Mycosis Fungoides. Polymerase chain reaction for T cell receptor gamma showed the same T-cell receptor gene rearrangement in both the temporal mass and the right submental lymph node.

CONCLUSION

ALHE with molecular evidence of monoclonality is extremely unusual, as is the association with nodal peripheral T-cell nodal lymphoma. The findings of this case support our hypothesis that ALHE might be an early form of T-cell lymphoma.

The gene trap approach in embryonic stem cells: the potential for genetic screens in mice

The gene trap approach in embryonic stem cells was developed as a means to screen for genes expressed during early postimplantation development in the mouse. We have validated the approach by showing that lacZ from the integrated vector is activated by splicing to endogenous exons and expressed in embryos in patterns that mimic those of the endogenous genes. These insertions can produce developmental defects in homozygous mice. The results indicate that a large screen of gene trap cell lines on the basis of embryonic lacZ expression is feasible and should provide a new source of genes, mouse mutants and mouse strains that express lacZ in particular domains and lineages. The gene trap approach could be extended to a smaller screen for genes based on mutant phenotypes.

Distinction of Benign Sebaceous Proliferations From Sebaceous Carcinomas by Immunohistochemistry

Sebaceous lesions, including sebaceous hyperplasia, sebaceomas, and sebaceous adenomas and carcinomas, are histologically distinctive adnexal proliferations with a spectrum of biological behavior ranging from benign to frankly malignant. The histologic distinction between sebaceous adenomas and carcinomas may be challenging, especially in cases showing atypical features and in small or partial biopsies. We studied multiple oncogenic and therapeutic related proteins by immunohistochemistry to identify differences in expression between benign and malignant sebaceous proliferations. A total of 27 cases, including 9 sebaceous adenomas, 4 sebaceomas, 8 sebaceous carcinomas, and 6 cases of sebaceous hyperplasia, were examined by immunohistochemistry, with antibodies directed against Ki-67 (MIB-1), bcl-2, p53, p21WAF1, p27Kip1, c-erbB-2 (Her-2/neu), CD117 (c-kit), cyclin D1, MDM2, CD99, MLH-1, and MSH-2. We found that sebaceous adenomas and sebaceomas stained like sebaceous hyperplasia did, whereas carcinomas had statistically significantly increased levels of p53 (50% versus 11%, respectively) and Ki-67 (30% versus 10%). The carcinomas also had significantly reduced levels of bcl-2 (7% versus 56%, respectively) and p21 (16% versus 34%) compared to the adenomas. Thus, a combination of several of these markers may be diagnostically useful in challenging cases. In addition, we found little or no Her-2/neu and CD117 staining, indicating that immunotherapy with Herceptin or Gleevac would likely not be useful for sebaceous carcinomas. Moreover, these results show that sebaceous adenomas and carcinomas are distinct neoplasms and provide no support for the theory that all sebaceous adenomas are truly malignant.

Rare primary CNS anaplastic large cell lymphoma in an immunocompetent adult: a clinical-pathologic case report and review case of the literature

OBJECTIVE AND IMPORTANCE

Isolated anaplastic large cell lymphoma (ALCL) presenting in the primary central nervous system is distinctly uncommon. The authors describe a case that clinically and radiographically simulated a primary glial neoplasm.

CLINICAL PRESENTATION

A 39-year-old immunocompetent male presented with seizures and a rapidly enlarging right occipital/parietal lesion. Magnetic resonance images demonstrated a right occipitoparietal lesion, hypodense on T1WI, with patchy contrast enhancement with gadolinium and significant white matter edema pattern on T2WI along with mass effect and midline shift.

INTERVENTION

The patient underwent a frameless stereotactic assisted needle biopsy. There appeared to be a clear demarcation between white matter and tumor with no obvious necrosis. Biopsy showed a proliferation of single cells and poorly cohesive groups of cells with large, pleomorphic nuclei, many containing prominent nucleoli, and a moderate amount of cytoplasm. Immunohistochemical staining revealed CD-30 and ALK-positivity typical of ALCL, a rare form of T-cell lymphoma. An extensive workup revealed neither systemic disease nor evidence of immunocompromise.

CONCLUSION

Reported in less than 20 patients, primary ALCL in an immunocompetent patient is rarely found intracranially; however, its ability to mimic glial neoplasms as well as other pathologies underlines its importance.

The effects of gp100 and tyrosinase peptide vaccinations on nevi in melanoma patients

BACKGROUND

A new approach to prevent disease recurrence in high-risk melanoma patients involves immunization with gp100 and tyrosinase peptides. This is the first study to examine the effects of such treatments on nevi.

DESIGN

We studied biopsies of 'clinically atypical' nevi from 10 patients before and after peptide vaccination. All had a cutaneous melanoma measuring at least 1.5 mm in depth, satellite metastases, or at least one positive lymph node. We performed immunohistochemical stains for CD3, CD4, CD8, MHC-I, MHC-II, CD1a, HMB-45, MART-1, tyrosinase, bcl-2, p53, and Ki-67 (mib-1).

RESULTS

Immunohistochemistry showed no differences in staining due to vaccination in either the immunologic or melanocytic markers. However, there was a significant increase in both p53 and bcl-2 staining, and a trend toward decreased Ki-67 staining, in the nevi post-treatment.

DISCUSSION

The primary goal of peptide vaccinations with gp100 and tyrosinase is to activate melanoma-specific T cells in order to prevent melanoma recurrence. Nevi were studied in order to assess the effects on benign melanocytes. No significant changes in lymphocytes, langerhans cells, expression of MHC antigens, or melanocytic markers were found. The increase in p53 and bcl-2 raises the possibility that vaccination with melanocytic antigens stimulates a response in benign melanocytes.