A meningeal myofibroblastic neoplasm related to solitary fibrous tumour and associated with a malignant neuroblastic element.

BACKGROUND: Solitary fibrous tumour (SFT) is a rare mesenchymal tumour now described at many locations, including the meninges. Intracranial SFT closely resembles meningioma clinically and radiologically, and, like meningioma, reports of meningeal SFT suggest a relatively benign behaviour after complete resection. Histopathological features distinguishing SFT from meningioma include variable cellularity, spindle cells arranged in fascicles, staghorn blood vessels and immunopositivity for CD34. CLINICAL PRESENTATION: The case is reported of a 60-year-old man with an anterior cranial fossa meningeal-based mass, which was resected. Histology showed some features in common with SFT (variable cellularity, spindled morphology, CD34 expression), but included an epithelioid element with cytokeratin and desmin immunopositivity, and lacked the characteristic vascular pattern of SFT. Histological features of meningioma were lacking. Recurrence of the tumour with extracranial extension 9 years later resulted in death of the patient. Histological examination revealed similar biphasic epithelioid and spindled CD34-immunopositive appearance to the earlier tumour, but in addition showed a high-grade element resembling olfactory neuroblastoma. CONCLUSION: This case report is of a meningeal-based mesenchymal neoplasm with histological similarities to SFT. Its morphology and immunophenotype, however, are distinct from SFT and hence it is proposed that it is a newly described entity. In addition, recurrence of the tumour with a high-grade neuroblastic element has, to our knowledge, not previously been described in SFT.

Biphasic solitary fibrous tumour: a report of two cases with epithelioid features.

We present two cases of solitary fibrous tumour (SFT) showing biphasic morphology with a spectrum of malignant epithelioid components. Slides prepared from formalin-fixed and paraffin-embedded tissue from both cases were stained with haematoxylin and eosin and by immunohistochemistry. Interphase fluorescent in situ hybridisation studies were performed in both cases using paraffin-embedded tissue to look for the t(X;18) translocation, thereby to exclude synovial sarcoma. Both cases showed biphasic morphology with some areas having typical benign spindled SFT morphology (including CD34 expression) and other areas having a malignant epithelioid appearance. In one of the cases, the epithelioid area, which was well circumscribed and showed packeting of cell groups, demonstrated expression of cytokeratin and epithelial cadherin but not of CD34. In the second case, the immunophenotype of the epithelioid component was similar to that of the benign SFT component. These findings suggest that epithelioid change in SFT shows a range of differentiation at one end, similar to that of a standard SFT, and at the other end, possibly acquiring epithelial characteristics.

Evaluation of perineurial differentiation in epithelioid sarcoma.

AIMS: To investigate the differentiation pattern of epithelioid sarcoma in terms of perineurial and endothelial differentiation, and its relationship to that of meningioma. METHODS AND RESULTS: Nine cases of epithelioid sarcoma and five cases of meningioma were studied in an immunohistochemical analysis of 'perineurial' antigens [GLUT-1, claudin-1, epithelial membrane antigen (EMA) and VE-cadherin] and of 'endothelial' antigens not present on normal perineurium (CD34, CD31, Fli-1). Both epithelioid sarcoma and meningioma showed frequent expression of the perineurial markers GLUT-1, claudin-1 and EMA. VE-cadherin was identified in one of five meningiomas, and in the only case of epithelioid sarcoma in which suitably fixed material was available. CD34 was expressed by all epithelioid sarcomas studied but by none of the meningiomas. Fli-1 was present in a substantial majority of epithelioid sarcomas and by all the meningiomas. CD31 was not detected in any epithelioid sarcoma or meningioma. CONCLUSIONS: The results were evaluated in the context of previous immunohistochemical, ultrastructural and genetic studies and suggest that epithelioid sarcoma may be a form of malignant perineurioma with a range of differentiation (epithelial features) akin to that seen in meningioma, reflecting the close relationship between perineurium and meningothelium.

Solitary epithelial cells in B cell gastric MALT lymphoma.

BACKGROUND: Gastric mucosa associated lymphoid tissue (MALT) lymphoma is a low grade B cell lymphoma histologically characterised by neoplastic B cells surrounding follicles in a marginal zone pattern and selectively infiltrating epithelium to form characteristic lymphoepithelial lesions. AIMS: To identify solitary epithelial cells in gastric MALT lymphoma and investigate their nature. METHODS: Anonymised endoscopic biopsies from eight B cell gastric MALT lymphomas and 10 control biopsies from chronic atrophic gastritis were selected. The numbers of solitary cytokeratin positive epithelial cells were assessed both semiquantitatively and quantitatively in immunostained sections. Chromogranin A expression was studied in sections consecutive to those stained for cytokeratin. RESULTS: Statistical analysis of the quantitative data confirmed that solitary epithelial cells were significantly more common in the lymphomas. The study of consecutive sections showed that the single cells express chromogranin A. CONCLUSIONS: The presence of solitary, cytokeratin positive epithelial cells within the neoplastic infiltrate is a characteristic feature of gastric B cell lymphoma. These solitary epithelial cells are of neuroendocrine origin.

Langerhans cell histiocytosis in sequential discordant lymphoma.

B cell non-Hodgkin lymphoma of the follicular subtype (grade 3/3) affecting the nasopharynx and breast, and containing foci of Langerhans cell histiocytosis, was diagnosed in a 56 year old white woman who was a longstanding heavy smoker. Four years before this she had developed stage 1a mixed cellularity Hodgkin lymphoma affecting the right inguinal region, which was treated by irradiation and chemotherapy without recurrence. Review of the original Hodgkin lymphoma histology demonstrated a small focus of Langerhans cell histiocytosis. This is thought to be the first recorded case of Langerhans cell histiocytosis occurring in a sequential discordant lymphoma. Its importance is discussed.

Reversal of glandular polarity in the lymphovascular compartment of breast cancer.

AIM: To investigate the polarity of breast invasive ductal carcinoma cells by comparing the polarity of the tumour located within lymphovascular spaces with that located in the extravascular compartment. METHODS: An immunohistochemical study identifying the apical HMFG-1, basolateral AUA-1, and basal laminin polarity markers of 11 cases of invasive ductal carcinoma (grades 1 or 2) metastatic to lymph nodes, all of which contained areas of tumour within and outside of lymphovascular spaces. RESULTS: Only one of 11 tumours had a focus of apparent reversed glandular polarity in the larger extravascular tumour compartment (with AUA-1 present internally and HMFG-1 expressed externally on tumour clumps), but six of the 11 tumours showed reversed glandular polarity (either with AUA-1, or HMFG-1, or both) within the very much smaller lymphovascular space tumour compartment. Laminin was not identified in association with lymphovascular tumour. CONCLUSIONS: Reversed glandular polarity in invasive ductal breast carcinomas was identified and was significantly more frequent within vessels than outside of them. Reversal of tumour glandular polarity within lymphovascular spaces allows direct interaction between apical domain-type molecules-which are then aberrantly expressed on the external surface of tumour clumps-and lymphovascular endothelium. Such interactions may affect the establishment of metastatic disease.

Specificity of lymphoreticular accumulation of prion protein for variant Creutzfeldt-Jakob disease.

BACKGROUND: Immunocytochemical accumulation of prion protein (PrP) in lymphoid tissues is a feature of variant Creutzfeldt-Jakob disease (vCJD) that has been used both to aid in the diagnosis of patients and as a basis of large scale screening studies to assess the prevalence of preclinical disease in the UK. However, the specificity of this approach is unknown. AIM: To assess the specificity of lymphoreticular accumulation of PrP for vCJD by examining a range of human diseases. METHODS: Paraffin wax embedded lymphoreticular tissues from patients with several reactive conditions (58 cases), tumours (27 cases), vCJD (54 cases), and other human prion diseases (56 cases) were assessed. PrP accumulation was assessed by immunocytochemistry using two different monoclonal anti-PrP antibodies and a sensitive detection system. RESULTS: All cases of vCJD showed widespread lymphoreticular accumulation of PrP; however, this was not seen in the other conditions examined. CONCLUSION: Lymphoreticular accumulation of PrP, as assessed by immunocytochemistry, appears to be a highly specific feature of vCJD.

Perianal Hodgkin's lymphoma complicating Crohn's disease.

BACKGROUND: The perianal region is a very rare location for Hodgkin's lymphoma, and clinicians may often neglect the diagnosis in patients with inflammatory bowel disease. PATIENT PRESENTATION: We present a case of perianal Hodgkin's lymphoma in patient with Crohn's disease who was on long-term immunosuppression and whose symptoms would normally be attributed to Crohn's disease. Diagnosis was based on the morphological appearance of atypical cells in the lamina propria and the immunohistochemical profile of Reed Sternberg and Hodgkin's cells, showing co-expression of CD15 and CD30. CONCLUSION: Perianal complaints in patients with inflammatory bowel disease may be a manifestation of other pathology. Hodgkin's lymphoma could be a progression in the chronically inflamed tissue in this unusual location.

Immunohistochemical expression of CD10 and t(14;18) chromosomal translocation may be indicators of follicle centre cell origin in nodal diffuse large B-cell lymphoma.

AIMS: Although diffuse large B-cell lymphoma is categorized as a distinct entity in the REAL classification of lymphomas, it represents a heterogeneous group of neoplasms. A subgroup is probably of follicle centre cell origin and may evolve from a pre-existing follicular lymphoma. The t(14;18) chromosomal translocation can be demonstrated in the majority of follicular lymphomas and the aim of this study was to investigate the prevalence of t(14;18) translocation in a series of de novo nodal diffuse large B-cell lymphomas. We correlated this with the immunohistochemical expression of CD10, bcl2 and bcl6, markers which are usually expressed by the neoplastic cells in follicular lymphomas. We also correlated these parameters with the presence or absence of p53 protein expression by the neoplastic cells. METHODS AND RESULTS: Nodal diffuse large B-cell lymphomas (n=34) were stained immunohistochemically with monoclonal antibodies to CD10, bcl2, bcl6 and p53 (D07). Polymerase chain reaction (PCR) for the t(14;18) translocation was also performed. Fourteen, 24 and 29 (41%, 71%, 85%) cases exhibited positivity for CD10, bcl2 and bcl6, respectively. In 12 cases there was positivity with D07 (35%). By PCR, the t(14;18) translocation was identified in five cases (15%), four of which were positive for CD10 and bcl2 and all of which were positive for bcl6. One of five cases positive for the chromosomal translocation exhibited positivity with D07. CONCLUSIONS: In this study the t(14;18) translocation was identified in 15% of diffuse large B-cell lymphomas, all but one of which exhibited positivity for CD10, bcl2 and bcl6. These may represent cases of follicle centre cell origin which may or may not have evolved from a pre-existing follicular lymphoma. It is possible that positivity for CD10 especially may identify cases which are of follicle centre cell origin and that the absence of t(14;18) translocation in some of these cases may reflect the fact that the translocation cannot normally be demonstrated in all follicular lymphomas. Whether the presence or absence of the translocation and the immunophenotype are prognostically important should be investigated further.

Malignant mesothelioma: PAS-diastase positivity and inversion of polarity in intravascular tumour.

AIMS: Periodic acid-Schiff (PAS)-diastase-positive material was identified within pseudoglandular structures within the small intravascular component of two pleural malignant mesotheliomas. The aim of this study was to ascertain the nature of this material and to asses the polarity of the cells forming the pseudoglandular structure. METHODS AND RESULTS: Immunohistochemistry was performed using antibodies to laminin and type IV collagen and the antibody HBME-1. These demonstrated the material to be basement membrane rather than mucin. The apical polarity marker HBME-1 was not related to the internal pseudoglandular structure but stained the periphery of intravascular tumour clumps. CONCLUSIONS: Pseudoluminal PAS-diastase-positive material in malignant mesothelioma may easily be mistaken for epithelial mucin, leading to an erroneous diagnosis of adenocarcinoma. The presence of basement membrane material in pseudolumina, as defined by the presence of laminin and type IV collagen, surrounded by tumour cells whose external surface expresses the apical polarity marker HBME-1 implies inversion of polarity of tumour cells within vascular spaces.