Probing the strongly correlated magnetic state of Co2C nanoparticles at low temperatures usingμSR

Co2C nanoparticles (NPs) are amongst transition metal carbides whose magnetic properties have not been well explored. An earlier study (Royet al2021J. Phys.: Condens. Matter33375804) showed that a pellet made from Co2C NPs exhibits exchange bias (EB) effect below a temperature,TEB= 50 K and a spin glass (SG) feature emerges belowTSG= 5 K. In the current study we use magnetic, electrical transport, specific heat, and muon spin rotation (μSR) measurements to explore further the magnetic properties of a pellet made with 40 nm diameter pure Co2C NPs. We uncover the onset of Kondo localization at Kondo temperatureTK(= 40.1 K), which is close to the onset temperature (TEB) of the EB effect. A crossover from the Kondo-screened scenario to the Ruderman-Kittel-Kasuya-Yosida interaction-dominated regime is also observed forT Collapse

Key Words

• Kondo effect
• exchange bias
• magnetic nanoparticles
• muon spin relaxation
• spin glass

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Affiliation(s)

Nirmal Roy Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India
P C Mahato Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India
Suprotim Saha Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India
M Telling ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot Oxon OX11 0QX, United Kingdom
J S Lord ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot Oxon OX11 0QX, United Kingdom
D T Adroja ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot Oxon OX11 0QX, United Kingdom Highly Correlated Matter Research Group, Physics Department, University of Johannesburg, PO Box 524, Auckland Park 2006, South Africa
S S Banerjee Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India

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Exploring a low temperature glassy state, exchange bias effect, and high magnetic anisotropy in Co2C nanoparticles

It is interesting to explore the connections between the exchange bias effect (EBE) and magnetic anisotropy (MA). It is often found that materials exhibiting a strong EBE also have enhanced MA. Here we explore 40 nm diameter Co₂C nanoparticles (NPs) that exhibit ferromagnetism with a blocking temperature exceeding 300 K. We report the first observation of EBE in these Co₂C NPs below 50 K. The effect arises from the exchange coupling of frozen ferromagnetic spins with a freely rotatable spin component. The dynamics of the freely rotatable component freezes in a temperature range between 5 K to 20 K resulting in low-temperature coexistence of a glassy behavior along with ferromagnetism. In fact, Co₂C displays a unique separation of onset temperatures of spin freezing (∼20 K), vanishing of EBE (∼50 K), and magnetic blocking (⩾450 K). Our calculations show that Co₂C NPs have a core-shell structure. Our study suggests that modifying chemical co-ordination in the shell is one of the effective routes to manipulating MA compared to manipulating EBE.

Water mediated dielectric polarizability and electron charge transport properties of high resistance natural fibers

Recent studies showed that silk and human hair fibers develop thermoelectric properties at optimal water, temperature and light conditions. The nature of charge carriers and the role of water in mediating charge conduction in these fibers is an unexplored issue. By studying four different classes of natural fibers, viz., silk cocoon, human hair, jute and corn silk, we uncover their common electrical transport properties and its dependence on water concentration and temperature. All these fibers uniformly exhibit nonlinear, hysteretic current - voltage characteristics, which scale with water concentration. The optimal electrical conductivity shows thermally activated hopping transport mechanism. Scanning tunneling microscope (STM) and dielectric measurements of silk cocoon fibers showed the electronic density of states and dielectric properties of the hydrated medium enhances with water concentration. Electron paramagnetic resonance (EPR) study reveals that the charge carriers in these membranes are electronic in nature. Our results are explained through the mechanism of hopping of a Polaron, which is an electron surrounded by positive charge fluctuations created by water molecules. The mechanism unravels the peculiar role water plays in mediating electrical activity in these membranes and also opens the possibility for exploring such charge transport mechanism in other biological membranes.

Evidence of magneto-structural coupling affecting magnetic anisotropy in a cobalt nano-composite

By investigating temperature dependent structural and magnetic properties of cobalt (Co) embedded within nanoporous anodized alumina template, we observe changes in the easy axis of Co magnetization and an unusual increase in its saturation magnetization below a temperature T _cr. Analysis of our M(H) data reveals that the magnetized volume of the sample increases rapidly as T falls below T _cr. To understand these features we perform micro-magnetic simulations for a single Co-nanopillar wherein by varying its magneto-crystalline anisotropy energy we are able to show that the changes observed near T _cr are related to the changes in the magnetic anisotropy of the nanopillar. We propose crystallographic structural distortions trigger changes in the balance between shape and magneto-crystalline anisotropy in our nanopillar. Our results suggest interplay between magnetism, structure and magnetic anisotropy in low dimensional Co-nanopillars, which can be modified with temperature of the system.

Negative velocity fluctuations and non-equilibrium fluctuation relation for a driven high critical current vortex state

Under the influence of a constant drive the moving vortex state in 2H-NbS₂ superconductor exhibits a negative differential resistance (NDR) transition from a steady flow to an immobile state. This state possesses a high depinning current threshold (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\boldsymbol{I}}}_{{\boldsymbol{c}}}^{{\boldsymbol{h}}}$$\end{document}Ich) with unconventional depinning characteristics. At currents well above \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\boldsymbol{I}}}_{{\boldsymbol{c}}}^{{\boldsymbol{h}}}$$\end{document}Ich, the moving vortex state exhibits a multimodal velocity distribution which is characteristic of vortex flow instabilities in the NDR regime. However at lower currents which are just above \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\boldsymbol{I}}}_{{\boldsymbol{c}}}^{{\boldsymbol{h}}}$$\end{document}Ich, the velocity distribution is non-Gaussian with a tail extending to significant negative velocity values. These unusual negative velocity events correspond to vortices drifting opposite to the driving force direction. We show that this distribution obeys the Gallavotti-Cohen Non-Equilibrium Fluctuation Relation (GC-NEFR). Just above \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\boldsymbol{I}}}_{{\boldsymbol{c}}}^{{\boldsymbol{h}}}$$\end{document}Ich, we also find a high vortex density fluctuating driven state not obeying the conventional GC-NEFR. The GC-NEFR analysis provides a measure of an effective energy scale (E_eff) associated with the driven vortex state. The E_eff corresponds to the average energy dissipated by the fluctuating vortex state above \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\boldsymbol{I}}}_{{\boldsymbol{c}}}^{{\boldsymbol{h}}}$$\end{document}Ich. We propose the high E_eff value corresponds to the onset of high energy dynamic instabilities in this driven vortex state just above \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\boldsymbol{I}}}_{{\boldsymbol{c}}}^{{\boldsymbol{h}}}$$\end{document}Ich.

Regressed Cutaneous Malignant Melanoma Mimicking Lymphoma: A Potential Diagnostic Pitfall

We report 2 cases of partially regressed malignant melanoma in which the brisk lymphocytic response closely resembled mycosis fungoides in 1 case and nodular sclerosing Hodgkin lymphoma in the other. Striking epidermotropism was present in both cases. The lymphocytes were predominantly of T8 cytotoxic subtype, and oligoclonal T-cell expansion was detected in 1 of the cases. The scanty residual melanoma cells were highlighted with HMB45 and S100 protein. We highlight the features of regression in melanoma that may lead to an erroneous diagnosis of lymphoma and discuss the finding of oligoclonal T-cell expansion in regressed melanocytic lesions.

Fabrication of single and coupled metallic nanocantilevers and their nanomechanical response at resonance

We fabricate and explore the resonance characteristics of self-supporting thin film based metallic nanocantilever systems. Nanocantilevers of Au and Ag are fabricated from self-supporting (polycrystalline) thin films (∼100 nm) grown via a surfactant mediated process. Focused ion beam assisted milling and manipulation techniques are used to fabricate the nanocantilevers. The resonance characteristics of the cantilevers are investigated by the piezoelectric base excitation method and the frequencies of their first resonance modes are determined by digitally processing and analysing scanning electron microscopy images captured during the study. The resonance characteristics of the nanocantilevers are observed to deviate from the Euler-Bernoulli description. We suggest a polynomial expression to describe the peculiar dimensional dependence of resonance frequency of a mechanically vibrating nanocantilever, where the zeroth order term in the polynomial expression represents an Euler-Bernoulli like form. We also demonstrate a fabrication and measurement technique for an elastically coupled Au nanocantilever system and analysis of its vibration characteristics by means of an analogous mass-spring system.

High sensitivity differential magneto-optical imaging with a compact Faraday-modulator

We present here the design of a sensitive compact Faraday-modulator (CFM) based optical magnetometer for imaging the distribution of weak local magnetic fields inside hysteretic magnetic materials. The system developed has a root-mean-square noise level of 50 mG Hz(-1/2) at a full frame rate of 1 fps (frame per second) with each frame being of size 512 × 512 pixels. By measuring the local magnetic field distribution in different superconducting samples we show that our magnetometer provides an order of magnitude improvement in the signal-to-noise ratio at low fields as compared to ordinary magneto-optical imaging technique. Moreover, it provides the required sensitivity for imaging the weak magnetization response near a superconducting transition where a number of other imaging techniques are practically unviable. An advantage of our CFM design is that it can be scaled in size to fit into situations with tight space constraints.

Large low-frequency fluctuations in the velocity of a driven vortex lattice in a single crystal of 2H-NbSe2 superconductor

The driven state of a well-ordered flux line lattice in a single crystal of 2H-NbSe2 in the time domain has revealed the presence of substantial fluctuations in velocity, with large and distinct time periods ( approximately seconds). A superposition of a periodic drive in the driven vortex lattice causes distinct changes in these fluctuations. We propose that prior to the onset of the peak effect there exists a heretofore unexplored regime of coherent dynamics, with unexpected behavior in velocity fluctuations.

The myofibroblast and its tumours

Tumours and tumour-like lesions of myofibroblasts may present diagnostic difficulty because of their rarity and because of uncertainties in identifying the myofibroblast. The objectives of this review are to provide a definition of the myofibroblast and an account of its biology for facilitating an understanding of the cell and of myofibroblastic lesions; and to describe, in the context of common diagnostic problems, the features of benign and malignant myofibroblastic lesions. The main characteristics of the myofibroblast include a spindled or stellate morphology; immunostaining for alpha-smooth muscle actin and the extra domain A variant of cellular fibronectin; and an ultrastructure of rough endoplasmic reticulum, peripheral contractile filaments and the cell-to-matrix junction known as the fibronexus. On this basis, lesions traditionally regarded as myofibroblastic are shown to vary in their level of differentiation, and some appear to be smooth muscle rather than myofibroblastic. Immunohistochemistry and electron microscopy, used together, are emphasised as being important for maximum diagnostic confidence in some myofibroblastic lesions.

Biocontrol of larval mosquitoes by Acilius sulcatus (Coleoptera: Dytiscidae)

Background

Problems associated with resistant mosquitoes and the effects on non-target species by chemicals, evoke a reason to find alternative methods to control mosquitoes, like the use of natural predators. In this regard, aquatic coleopterans have been explored less compared to other insect predators. In the present study, an evaluation of the role of the larvae of Acilius sulcatus Linnaeus 1758 (Coleoptera: Dytiscidae) as predator of mosquito immatures was made in the laboratory. Its efficacy under field condition was also determined to emphasize its potential as bio-control agent of mosquitoes.

Methods

In the laboratory, the predation potential of the larvae of A. sulcatus was assessed using the larvae of Culex quinquefasciatus Say 1823 (Diptera: Culicidae) as prey at varying predator and prey densities and available space. Under field conditions, the effectiveness of the larvae of A. sulcatus was evaluated through augmentative release in ten cemented tanks hosting immatures of different mosquito species at varying density. The dip density changes in the mosquito immatures were used as indicator for the effectiveness of A. sulcatus larvae.

Results

A single larva of A. sulcatus consumed on an average 34 IV instar larvae of Cx. quinquefasciatus in a 24 h period. It was observed that feeding rate of A. sulcatus did not differ between the light-on (6 a.m. – 6 p.m.), and dark (6 p.m. – 6 a.m.) phases, but decreased with the volume of water i.e., space availability. The prey consumption of the larvae of A. sulcatus differed significantly (P < 0.05) with different prey, predator and volume combinations, revealed through univariate ANOVA. The field study revealed a significant decrease (p < 0.05) in larval density of different species of mosquitoes after 30 days from the introduction of A. sulcatus larvae, while with the withdrawal, a significant increase (p < 0.05) in larval density was noted indicating the efficacy of A. sulcatus in regulating mosquito immatures. In the control tanks, mean larval density did not differ (p > 0.05) throughout the study period.

Conclusion

the larvae of the dytiscid beetle A. sulcatus proved to be an efficient predator of mosquito immatures and may be useful in biocontrol of medically important mosquitoes.

Mapping giant magnetic fields around dense solid plasmas by high-resolution magneto-optical microscopy

We investigate the distribution of magnetic fields around dense solid plasmas generated by intense p-polarized laser approximately 10(16) W cm(-2), 100 fs) irradiation of magnetic tapes, using high sensitivity magneto-optical microscopy. By investigating the effect of irradiation on the magnetic tape, we present evidence for axial magnetic fields and map out the spatial distribution of these fields around the laser generated plasma. By using the axial magnetic field distribution as a diagnostic tool we uncover evidence for angular momentum associated with the plasma.

Divergent differentiation in malignant melanomas: a review

The aim of this review was to document and discuss diagnostic problems associated with divergent differentiation ('metaplastic change') in malignant melanomas, defined as the development in these tumours of morphologically, immunohistochemically and/or ultrastructurally recognizable non-melanocytic cell or tissue components. Types of divergent differentiation reported in malignant melanoma include: fibroblastic/myofibroblastic, Schwannian and perineurial, smooth muscle, rhabdomyosarcomatous, osteocartilaginous, ganglionic and ganglioneuroblastic, neuroendocrine and probable epithelial. Divergent differentiation is certainly a rare phenomenon and, when it occurs, can be missed by unwary pathologists and lead to diagnostic uncertainty. A carefully chosen immunohistochemical panel and the input of electron microscopy can help to clarify the nature of the cellular differentiation of these tumours and lead to a correct final diagnosis. The clinical significance of such aberrations is uncertain, nor are the underlying mechanisms as yet well defined.

Benign schwannoma in paranasal sinuses: a clinico-pathological study of five cases, emphasising diagnostic difficulties

OBJECTIVES

To highlight the difficulty in making a correct diagnosis of benign schwannoma in the paranasal region, to raise awareness of this rare condition, and to suggest the most appropriate treatment.

METHOD

Retrieval of cases retrospectively from archives of the histopathology department of a major UK cancer centre with central review of all cases.

RESULTS

Five cases were identified since 1990 and clinical and pathological features are summarised. Median follow up of patients was 8.1 years. Radiological appearances of local bone invasion and histological features of tumour unencapsulation and hypercellularity could give the mistaken impression of malignant disease and lead to unnecessary over-treatment.

CONCLUSION

Central pathological review and clinical awareness is required. Although local recurrence can occur, the prognosis is excellent. The treatment of choice is local excision. Radiotherapy can be considered, but in most cases it would incur unnecessary morbidity.

Nasal septal perforation and antiphospholipid syndrome (Hughes syndrome)

We present the case of a 19-year-old woman who developed a nasal septal perforation and atrophic rhinitis following septal surgery. During the subsequent five years, she also experienced intermittent episodes of swelling and ischaemia of the left foot, as well as livedo reticularis. Ultimately, haematological investigations revealed the presence of lupus anticoagulant and elevated antiphospholipid immunoglobulin M levels. A diagnosis of antiphospholipid syndrome (Hughes syndrome) was made.A search of the literature revealed that nasal septal perforation has been described in up to 0.8 per cent of patients with antiphospholipid syndrome. However, it is undescribed in the otorhinolaryngological literature. The impact of this syndrome on otorhinolaryngology practice is examined.

Instabilities in the vortex matter and the peak effect phenomenon

In single crystals of 2H-NbSe2, we identify for the first time a crossover from a weak collective to a strong pinning regime in the vortex state which is not associated with the peak effect phenomenon. Instead, we find the crossover is associated with an anomalous history dependent magnetization response. In the dc magnetic field (Bdc)-temperature (T) vortex matter phase diagram we demarcate this pinning crossover boundary. We also delineate another boundary which separates the strong pinning region from a thermal fluctuation dominated regime, and find that a peak effect appears on this boundary.

Malignant melanoma with neuroendocrine differentiation: clinical, histological, immunohistochemical and ultrastructural features of three cases

AIM

To document the clinical, histological, immunohistochemical and ultrastructural features of three malignant melanomas showing neuroendocrine differentiation.

METHODS AND RESULTS

Three patients, two with primary cutaneous melanoma and one with nasal mucosal melanoma, subsequently developing or simultaneously presenting with metastatic malignant melanoma, were studied by conventional histological technique, immunohistochemistry of formalin-fixed paraffin-wax embedded tissues, and electron microscopy of epoxy-resin-embedded tumour tissue. Tumours showed either small cell or conventional malignant melanoma cell morphology. One of the three primary melanocytic lesions (the nasal melanoma) exhibited neuroendocrine differentiation immunohistochemically. All three metastatic malignant melanomas showed, in varying combinations, immunohistochemical and ultrastructural evidence for neuroendocrine differentiation: they were positive for the melanocytic markers, S100 protein, HMB-45, Melan-A and tyrosinase, and the neuroendocrine markers chromogranin, synaptophysin and neurofilament protein. Ultrastructural study in two of the metastases revealed neuroendocrine granules but no lattice-bearing melanosomes.

CONCLUSIONS

The cases described are the most comprehensively investigated malignant melanomas showing neuroendocrine differentiation to date, and the first to document neuroendocrine differentiation ultrastructurally in these tumours. Malignant melanoma with neuroendocrine differentiation therefore needs to be recognized among the other, better known variants of malignant melanoma.

Metastatic small cell malignant melanoma: a case requiring immunoelectronmicroscopy for the demonstration of lattice-deficient melanosomes

A case of metastatic malignant melanoma exhibiting small cell morphology is described. The patient had had a previous primary nodular small cell melanoma. The metastatic tumor was examined by conventional histology, light microscope immunohistochemistry, conventional electron microscopy, and ultrastructural immunolabeling. It consisted of small cells, which, however, varied in size and were present in distinct but merging areas. Tumor cells were negative for S-100 protein and very focally positive for cytokeratin: these findings in combination with small cell morphology suggested the possibility of small cell carcinoma. However, other melanocytic markers were positive. Neuroendocrine markers were negative. By electron microscopy, tumor cells lacked unambiguous melanosomes but contained paranuclear aggregates of nondescript granules. Following ultrastructural immunolabeling, these were found to be decorated with gold-labeled HMB-45 antibodies, thereby confirming them as lattice-deficient melanosomes. This tumor is an uncommon example of malignant melanoma where immunoultrastructural analysis helped clarify the nature of otherwise nondescript granules as true but lattice-deficient melanosomes. This is also the first case of small cell melanoma to be studied by electron microscopy.

Foci of amorphous/granulofilamentous matrix in the extracellular domain of tumours. 2. Immunohistochemical and immunogold characterization of a fibronectin-rich matrix component

The term FEAM (foci of extracellular amorphous matrix) has been used for discretely outlined areas of moderately dense material having a filamentous/granular substructure located in the extracellular matrix of tumours. In spite of being widespread in mesenchymal tumours especially, and often abundant, they have received little attention in terms of structure, composition and origin. Mostly, they have been regarded as a variant or a product of lamina ('basement membrane material'). However, they also appear in tumours whose cells should and do lack a lamina, such as giant-cell fibroblastoma and solitary fibrous tumour. This paper describes their fine structure in a variety of predominantly mesenchymal tumours, and documents their composition using light microscope immunostaining and immunogold labelling. Small amounts of type IV collagen and laminin were found focally and inconsistently among the five tumours by light microscope immunostaining, but fibronectin was strongly and consistently identified. Strong fibronectin staining was also identified by immuno-electronmicroscopy. These data suggest that FEAM represent a fibronectin-rich matrix constituent, which might be a common final product of either lamina or the external component of the subplasmalemmal linear density (focal adhesion). There is little support light microscopically for a relationship to immune-complexes or cryoglobulins.

Vortex nanoliquid in high-temperature superconductors

Using a differential magneto-optical technique to visualize the flow of transport currents, we reveal a new delocalization line within the reversible vortex liquid region in the presence of a low density of columnar defects. This line separates a homogeneous vortex liquid, in which all the vortices are delocalized, from a heterogeneous "nanoliquid" phase, in which interconnected nanodroplets of vortex liquid are caged in the pores of a solid skeleton formed by vortices pinned on columnar defects. The nanoliquid phase displays high correlation along the columnar defects but no transverse critical current.

Post-transplant T-cell lymphoproliferative disorder/T-cell lymphoma: a report of three cases of T-anaplastic large-cell lymphoma with cutaneous presentation and a review of the literature

AIMS

To report the clinical, pathological and immunohistochemical features of three cases of post-transplant T-cell lymphoproliferative disorder (T-PTLD) T-cell lymphoma with primary cutaneous presentation.

METHODS AND RESULTS

Three cases of primary cutaneous post-transplantation anaplastic large-cell lymphomas occurred in renal transplant recipients and were shown to display a T-cell immunophenotype; all were ALK 1 protein and EMA negative and two were Epstein-Barr virus positive using in-situ hybridization. Two displayed a CD4+ phenotype, two were focally CD56+ and all three were negative for the cytolytic enzyme granzyme B. In two cases monoclonality was established by T-cell receptor gene rearrangement study. All presented with nodular cutaneous involvement and all were ultimately fatal.

CONCLUSION

T-PTLDs are uncommon histological subtypes both in a general context and associated with cutaneous presentation. Our findings suggest clinicopathological and immunophenotypic similarities to primary cutaneous anaplastic large-cell lymphoma but with a progressive clinical behaviour similar to previously reported T-PTLD and to systemic nodal ALK- anaplastic large-cell lymphoma.

Adenoid Cystic/Basal Cell Carcinoma of the Prostate

Adenoid cystic/basal cell carcinoma (ACBCC) of the prostate has been considered to have indolent biologic potential. However, outcome data are scant, with only one documented metastasis and death. We describe clinicopathologic features of ACBCC in 19 patients and document outcome in 15. Patients ranged in age from 43 to 83 years. All but one presented with urinary obstruction. ACBCC was diagnosed by transurethral resection in 15 cases, by needle biopsy in 3 cases, and unexpected in 1 case. Four patients had concurrent acinar adenocarcinoma. Histologically, cribriform or adenoid cystic patterns predominated in 12 cases and basal cell carcinoma pattern in 7. Five cases had prominent perineural invasion. ACBCC was immunoreactive for p63 and cytokeratins 7 and 34 beta E12 but not cytokeratin 20. After diagnosis, 5 patients underwent radical prostatectomy, 2 underwent pelvic exenteration, and the rest had no treatment. ACBCC showed extraprostatic extension in 5 cases and involved the bladder margin in 3. Metastases developed in 4 (21%) patients: liver (2), lung (2), bowel (1), and corpus cavernosum (1). In 15 cases with follow-up (0.3-11.8 years), two patients died of cancer (at 1.5 and 3 years after diagnosis), 3 remain alive with cancer, and 10 have no evidence of cancer. Thus, ACBCC of the prostate is a potentially aggressive neoplasm requiring ablative therapy.

First-order phase transition from the vortex liquid to an amorphous solid

We present a systematic study of the topology of the vortex solid phase in superconducting Bi2Sr2CaCu2O8 samples with low doses of columnar defects. A new state of vortex matter imposed by the presence of geometrical contours associated with the random distribution of columns is found. The results show that the first-order liquid-solid transition in this vortex matter does not require a structural symmetry change.

Melting of "porous" vortex matter

Bitter decoration and magneto-optical studies reveal that in heavy-ion irradiated superconductors, a "porous" vortex matter is formed when vortices outnumber columnar defects. In this state ordered vortex crystallites are embedded in the "pores" of a rigid matrix of vortices pinned on columnar defects. The crystallites melt through a first-order transition while the matrix remains solid. The melting temperature increases with density of columnar defects and eventually turns into a continuous transition. At high temperatures a sharp kink in the melting line is found, signaling an abrupt change from crystallite melting to melting of the rigid matrix.

Incomplete excision of basal cell carcinoma: a prospective multicentre audit

The audit of incomplete excision of basal cell carcinoma can be used as a parameter for clinical governance in plastic surgery units. However, there are no national standards, and all the previous reports from the UK have been retrospective and from regional units only. This 1 year prospective audit was undertaken simultaneously in the plastic surgery units of three different categories of hospital: a regional plastic surgery unit (University Hospital of South Manchester), a supraregional cancer hospital (Christie Hospital) and a district general hospital (Royal Bolton Hospital). A total of 757 lesions were excised from 600 patients, with 34 lesions (4.5%) being incompletely excised. The incidences of incomplete excision were similar in the regional unit (3.2%) and the district general hospital (3.1%), but higher in the supraregional cancer hospital (7.5%). The commonest site for incomplete excision was the eyebrow, followed by the postauricular area, the nose and the temple. There were no statistically significant differences in the distributions of the age and sex of the patients, the site and size of the lesions or the methods of repair between the three hospitals. However, there were significant differences in the distribution of syndromal, multiple and recurrent lesions, the grade of surgeon, and the clinical and histological subtypes. When the various confounding factors were adjusted by logistic regression, the variables most likely to have affected the incidence of incomplete excision were found to be grade of surgeon, minimal excision margin and histological subtype.

A study of eleven cutaneous malignant melanomas in adults with small-cell morphology: emphasis on diagnostic difficulties and unusual features

AIMS

To describe the clinicopathological and immunohistochemical features of cutaneous malignant melanomas with a pure or mixed small-cell pattern in 11 adult patients, and to discuss the diagnostic difficulties encountered.

METHODS AND RESULTS

Haematoxylin and eosin-stained sections of each case of cutaneous small-cell malignant melanoma, together with locally recurrent skin lesions and, where available, metastatic deposits, were re-examined. Available immunohistochemical sections were evaluated. Clinical follow-up data were obtained in each case. One patient presented with metastatic disease, the others presented with cutaneous lesions. Suggested initial diagnoses included malignant melanoma, non-Hodgkin's lymphoma, Merkel cell carcinoma and sarcoma. All the tumours were in the vertical growth phase. Nine had a junctional component, often inconspicuous. The lesions showed either a pure small-cell pattern or a mixed pattern with more conventional areas. In one case, there was colonization of a basal cell carcinoma by invasive malignant melanoma. Variable retention of small-cell morphology in local recurrences and metastases was observed, although in some cases more typically pleomorphic cells were present. In the cases tested, there was strong immunostaining for S100 protein and NKI-C3, and variable immunostaining for HMB45 and Melan-A. Non-melanocytic markers were negative.

CONCLUSIONS

The possibility of a small-cell malignant melanoma should be considered in the assessment of cutaneous and non-cutaneous small-cell neoplasms. The correct diagnosis requires careful evaluation for junctional activity, melanin production and the use of a panel of melanocytic markers.

Amphicrine carcinoma of breast with giant granules: an immunohistochemical, histochemical and ultrastructural study

A moderately differentiated grade 2 invasive ductal carcinoma was diagnosed in the right breast of an 81-year-old woman. The uniform nuclear profiles and moderately abundant granular cytoplasm suggested a neuroendocrine tumour and a Grimelius stain was positive. Neurone specific enolase, synaptophysin and somatostatin stained positively, and casein was interpreted as positive although with some background staining. By electron microscopy, tumour cells possessed desmosomes, tonofibrils, intercellular lumina, lamina and dense granules. Rounded dense granules 160-480 nm in diameter resembled neuroendocrine granules. They were found in both luminal and basal areas. Fewer and much larger ('giant') granules had a rounded profile and were up to 5 microm across. The smaller cytoplasmic granules were mostly Grimelius-positive while giant granules were negative. The smaller granules were also uranaffin-positive, but no uranaffin-positive cytoplasmic giant granules were encountered. Both small and giant granules were observed in lumina, and here both were uranaffin-positive. Intraluminal giant granules had a substructure of small pale lipid-like lacunae, and some had irregular profiles. The exceptional size of these exocrine granules is emphasised, and the nature of both the small and giant granules discussed in this amphicrine carcinoma.

Temperature variations of the disorder-induced vortex-lattice-melting landscape

Differential magneto-optical imaging of the vortex-lattice-melting process in Bi(2)Sr(2)CaCu(2)O(8) crystals reveals unexpected effects of quenched disorder on the broadening of the first-order phase transition. The melting patterns show that the disorder-induced melting landscape T(m)(H,r) is not fixed, but rather changes dramatically with varying field and temperature along the melting line. The changes in both the scale and shape of the landscape are found to result from the competing contributions of different types of quenched disorder which have opposite effects on the local melting transition.

A study of four cases of extra-orbital giant cell angiofibroma with documentation of some unusual features

AIMS

To document the clinical, light microscopic, immunohistochemical and ultrastructural features of four cases of extra-orbital giant cell angiofibromas.

METHODS AND RESULTS

Sections of formalin-fixed paraffin-embedded specimens were studied by haematoxylin and eosin, reticulin and immunohistochemical stains. Electron microscopy was carried out in two cases on tissue fixed in formalin. The age of the patients ranged from 30 to 41 years. Two patients presented with a soft tissue swelling in the left groin, one patient had a left axillary soft tissue lump and one patient presented with a parotid lump. All lesions were well circumscribed and contained variably cellular and vascularized tissue composed of round to spindle cells with a patternless arrangement, scattered multinucleate giant cells and pseudovascular spaces conforming to the description of giant cell angiofibroma. Mononuclear and multinucleate tumour cells were both positive for vimentin and CD34; one tumour exhibited focal S100 protein and GFAP positivity. Both of the tumours examined by electron microscopy showed fibroblastic features, but in addition one contained cells having Schwannian features. All four patients were well without recurrent disease on follow-up (average 25 months).

CONCLUSION

Giant cell angiofibroma shares many features with solitary fibrous tumour and giant cell fibroblastoma and shows a wider distribution than initially recognized. Rarely, Schwannian differentiation may be observed in these tumours.

Peripheral primitive neuroectodermal tumour (pPNET) of the cerebellopontine angle presenting in adult life

We report a case of a peripheral neuroectodermal tumour (pPNET) of the cerebellopontine angle of a 67-year-old woman. The patient's age at presentation was highly unusual. This case highlights the difficulties encountered, both clinically and pathologically, in securing the correct diagnosis of such a rare condition presenting in this relatively inaccessible area. The development of the nomenclature and classification of neuroectodermal tumours is traced. Recent advances in immunohistochemistry and genetic typing have shown the close relationship between pPNET and the previously difficult to classify Ewing's sarcoma and Askin's tumour.

Follicular lymphoid hyperplasia of the hard palate and oral mucosa: report of three cases and a review of the literature

AIMS

To bring to wider attention this uncommon, poorly understood entity which may closely resemble, clinically and morphologically, follicular lymphoma.

METHODS AND RESULTS

We report three cases of follicular lymphoid hyperplasia of the hard palate and oral mucosa which caused diagnostic difficulties for the referring pathologists. The clinicopathological features are described and integrated into a review of the 16 previously recorded cases. The condition most commonly presents as a slowly growing mass situated in the posterior hard palate but may present with multicentric oral lesions and lymphadenopathy. Morphologically, it is characterized by a dense follicular lymphoid infiltrate within the lamina propria which may show the classical features of benign reactive hyperplasia, but not uncommonly, indistinct germinal centres, ill-defined mantles and a lack of tingible-body macrophages are features which may lead to an erroneous diagnosis of follicular lymphoma.

CONCLUSIONS

Follicular lymphoid hyperplasia of the palate is a poorly recognized entity which is frequently confused with follicular lymphoma. Awareness of the entity combined with the use of immunohistochemistry for immunoglobulin light chains and bcl-2 protein allows a correct diagnosis to be made avoiding extensive investigation and aggressive treatment to the patient.

Monotypic angiomyolipoma of the nasal cavity: a heretofore undescribed occurrence

A monotypic angiomyolipoma of the nasal cavity in a 34-year-old woman is described. Tumor cells were spindled or epithelioid and contained glycogen and diastase-resistant PAS-positive granules. There were few mitoses, and necrosis was absent, indicating a benign tumor. The stroma was markedly vascular, and a few adipocytes were seen in one area. Cells were positive for melanocyte and muscle markers. Electron microscopy revealed abundant dense granules. Although melanin was absent histochemically, it was present using a chemical assay, and the granules may, therefore, be atypical melanosomes. Fine actin filaments, attachment plaques and lamina were present. Initial assessment of the lesion indicated malignant melanoma, but the immunostaining and histologic features indicated monotypic angiomyolipoma. To the best of our knowledge, this is the first such case in the nasal cavity.

Relapsing polychondritis associated with monoclonal gammopathy in a patient with myelodysplastic syndrome

Relapsing polychondritis is a rare condition characterized by inflammation and subsequent degeneration of cartilages. Deformity of the pinna, nasal saddling and stridor due to involvement of the cartilages of the respiratory tract may lead to patients being referred to the otolaryngologist for initial assessment and further management. Recent observations have suggested that relapsing polychondritis may occur as a paraneoplastic phenomenon in cases of myelodysplasia. The case of a patient with relapsing polychondritis, myelodysplastic syndrome and a monoclonal gammopathy is presented. The authors highlight the apparent existence of this association and encourage otolaryngologists to consider such possible links when cases of relapsing polychondritis present to the outpatients department.

Giant-cell fibroblastoma: a case report emphasising the presence of hyperplastic subplasmalemmal linear densities in continuity with granular matrices in the extracellular space

The histological, immunohistochemical and ultrastructural features of a case of giant-cell fibroblastoma from the soft tissues of the chest wall in a 48-year-old female are described with special reference to the cell surface and matrix. Subplasmalemmal linear densities (SLDs) characterised cell surfaces, and exhibited excessive development of the dense external component: foci of identical dense material were present in the matrix. The nature of these dense foci, both the external component of the SLD and those free in the extracellular space, was investigated by light microscope immunostaining for fibronectin, laminin and collagen IV. All three proteins stained vessels. There was weaker but positive staining for tumour cell surfaces and matrix, consistent with the widely dispersed nature of the dense foci. Given their fine structural appearance, these dense foci can be referred to as granular matrices. Given also that the matrix protein immunostaining pattern is consistent with the distribution of these granular matrices as observed by electron microscopy, they may be provisionally interpreted as a kind of basement-membrane-related granular matrix. The presence of these proteins emphasises the point that, while giant-cell fibroblastoma fibroblasts lack a lamina, they nevertheless bear basement-membrane-related proteins organised, however, in a non-laminate fashion. The observations reinforce the need to qualify immunostaining results by ultrastructural investigation in order to understand the organisation of immuno-detected proteins and are discussed in terms of their diagnostic and possible biological significance.

Morphological and immunophenotypic variations in malignant melanoma

A variety of cytomorphological features, architectural patterns and stromal changes may be observed in malignant melanomas. Hence, melanomas may mimic carcinomas, sarcomas, benign stromal tumours, lymphomas, plasmacytomas and germ cell tumours. Melanomas may be composed of large pleomorphic cells, small cells, spindle cells and may contain clear, signet-ring, pseudolipoblastic, rhabdoid, plasmacytoid or balloon cells. Various inclusions and phagocytosed material may be present in their cytoplasm. Nuclei may show bi- or multi-nucleation, lobation, inclusions, grooving and angulation. Architectural variations include fasciculation, whorling, nesting, trabeculation, pseudoglandular/pseudopapillary/pseudofollicular, pseudorosetting and angiocentric patterns. Myxoid or desmoplastic changes and very rarely pseudoangiosarcomatous change, granulomatous inflammation or osteoclastic giant cell response may be seen in the stroma. The stromal blood vessels may exhibit a haemangiopericytomatous pattern, proliferation of glomeruloid blood vessels and perivascular hyalinization. Occasionally, differentiation to nonmelanocytic structures (Schwannian, fibro-/myofibroblastic, osteocartilaginous, smooth muscle, rhabdomyoblastic, ganglionic and ganglioneuroblastic) may be observed. Typically melanomas are S100 protein, NKIC3, HMB-45, Melan-A and tyrosinase positive but some melanomas may exhibit an aberrant immunophenotype and may express cytokeratins, desmin, smooth muscle actin, KP1 (CD68), CEA, EMA and VS38. Very rarely, neurofilament protein and GFAP positivity may be seen.

Mesotheliomas with deciduoid morphology: a morphologic spectrum and a variant not confined to young females

Deciduoid mesotheliomas are rare with only four previously reported cases, all affecting the peritoneum of young females. We describe another six cases (three men and three women; age range 52-65 yrs, median 55 yrs; five peritoneal and one pleural). Three patients had an occupational history of asbestos exposure. The deciduoid appearance predominated in four cases, whereas in two it represented a minor component within conventional tubulopapillary epithelioid mesothelioma. All tumors were strongly cytokeratin-positive (including CK5/6) and all showed at least focal staining for thrombomodulin, HBME-1, and calretinin. All were negative for epithelial mucin (D/PAS), CEA, BerEP4, LeuM1 (CD15), CD21, CD35, and S100 protein. Five of six cases (83%) were vimentin-positive and two (33%) were focally positive for alpha-smooth muscle actin. A differential diagnosis of gastrointestinal autonomic nerve tumor (GANT) had been initially considered from the morphology of one case, and we found positivity for some of the "neuronal" markers described in GANTs. This prompted us to apply such a panel to the other five tumors, accepting that the cytokeratin positivity encountered in all of our cases would exclude GANT. All cases of deciduoid mesothelioma (100%) were positive for PGP 9.5 and NSE and four of six (66%) were positive for NKI/C3. Weak focal staining (<5% cells) for synaptophysin was seen in two of six tumors. All cases were chromogranin-negative. All cases examined by electron microscopy showed desmosomes and smooth microvilli without rootlets but no neuroendocrine granules. In conclusion, a deciduoid morphology appears to be part of the histopathologic spectrum encountered in epithelioid mesothelioma. This variant is not confined to female patients and occurs over a wider age range than previously recognized. The overlapping immunophenotype with GANTs illustrates that caution should be exercised when interpreting positivity for "neuronal" markers in this context. An immunohistochemical panel that includes cytokeratins should always be used.

Malignant melanoma showing ganglioneuroblastic differentiation: report of a unique case

We report a case of metastatic malignant melanoma in an inguinal lymph node, expressing ganglioneuroblastic differentiation. This was characterized by the presence of discrete nests and islands of large ganglion cells with abundant cytoplasm and eccentric nuclei with prominent nucleoli admixed with smaller primitive neuroblasts. The cells were separated by pale pink fibrillar material representing neuritic cell processes. These foci of ganglioneuroblastoma were seen over a background of an otherwise typical metastatic epithelioid, focally melanotic, malignant melanoma. Immunohistochemistry showed positivity for neurofilament, synaptophysin, chromogranin, vasoactive intestinal peptide, and glial fibrillary acidic protein in the areas with ganglioneuroblastic differentiation, but not in the melanocytic component. Conversely, HMB45 positivity was expressed by the melanocytic cells only. S-100 protein and Melan-A, a putative melanocytic marker, showed positivity in both melanocytic and ganglioneuroblastic components. Ultrastructurally, neuritic cell processes and dense core neurosecretory granules were identified in the ganglionic and neuroblastic cells. A subsequent nodal metastasis in the same region showed focal neuroblastic differentiation without the ganglionic element. No evidence of neuronal or ganglionic differentiation was seen in the primary skin melanoma.

Extra-medullary myeloid tumour (granulocytic sarcoma) is often misdiagnosed: a study of 26 cases

AIMS

To describe the clinicopathological and immunophenotypic features of 26 cases of extra-medullary myeloid tumour (EMMT)/granulocytic sarcoma, which remains poorly recognized and is frequently confused with malignant lymphoma, and to discuss the main diagnostic problems experienced by the referring pathologist.

METHODS AND RESULTS

Haematoxylin and eosin (H & E) sections of 26 cases of EMMT were re-examined. Immunostains for myeloperoxidase, lysozyme, neutrophil elastase, LCA, CD79a, CD20, CD43, CD45RO, CD3, CD30, CD15, CD68, MAC387, VS38C, MIC2, and the Leder stain for naphthol-ASD-chloroacetate esterase were performed on all cases. Clinical and follow-up data were obtained through a questionnaire to the referring pathologist or from the notes of the patients where available. In the 10 cases with known myeloproliferative disease, the initial diagnosis was correct in 10 whereas all cases presenting with EMMT without a previous history of myeloproliferative disorder had an initial incorrect diagnosis. The most common suggested diagnosis was that of a non-Hodgkin's lymphoma. The morphology of the tumours varied from well differentiated which included all stages of myeloid differentiation to poorly differentiated or blastic showing little or no evidence of myeloid differentiation. The proportion of positive cells for each stain varied. Chloroacetate esterase, myeloperoxidase and CD15 stained a large proportion of cells of the majority of the well differentiated tumours and a smaller proportion of the poorly differentiated/blastic tumours with very focal staining of some of the cases. Lysozyme and CD43 were the most sensitive of the markers staining a large proportion of cells of the majority of the tumours in both groups. Neutrophil elastase was the least sensitive of the markers of myeloid differentiation. CD79a, CD20, CD3 and CD30 were negative in all cases. CD43 was positive in all cases. CD68 stained a substantial number of cells in the majority of tumours. A smaller proportion of the tumours stained with MAC387. Four of the tumours showed positivity for MIC2. One tumour was positive for VS38C.

CONCLUSION

This series documents continuing difficulties in the diagnosis of EMMT. Even well differentiated tumours are frequently mistakenly diagnosed as malignant lymphomas when they present without any history of antecedent myeloproliferative disorder. Careful evaluation of morphology for evidence of myeloid differentiation and a high index of suspicion when confronted with a less differentiated neoplasm are required to avoid this important diagnostic error. We suggest that a panel which includes chloroacetate-esterase, myeloperoxidase, lysozyme and CD43, together with other B- and T-lineage markers, in particular CD79a and CD3 should be used to confirm the diagnosis.

Adenocarcinoma of the rete testis

Adenocarcinoma of the rete testis is a rare testicular tumour, which often presents late, with metastatic disease present in a significant proportion of patients. We record the clinicopathological findings in a man who presented with an apparently localized testicular tumour. He however went on to develop a rapidly progressive local recurrence and metastatic disease, despite primary radiotherapy. Detailed immunohistochemical examination was performed and we record positivity of this tumour for the recently developed markers HBME1 and thrombomodulin.

Schwannoma with features mimicking neuroblastoma: report of two cases with immunohistochemical and ultrastructural findings

OBJECTIVE

A study of two cases of a rare variant of benign schwannoma showing areas mimicking neuroblastoma/peripheral primitive neuroectodermal tumour (PNET).

METHODS

Sections of formalin fixed, paraffin embedded specimens were studied by tinctorial stains and immunohistochemistry, and the tissue retrieved from formalin was examined by electronmicroscopy in one case.

RESULTS

The tumours were small and subcutaneous. Both showed features of benign schwannoma; one had a multinodular plexiform pattern. In addition, rosette-like structures consisting of collagenous cores surrounded by small round cells or slightly larger epithelioid cells were present. Tumour cells were positive for S100 protein, Leu7, and in one case GFAP, but were negative for neurofilament protein, synaptophysin, and MIC2. Type IV collagen surrounded individual cells. Electronmicroscopy in case 2 confirmed schwannian features (lamina, processes) and failed to show features of neuroblastoma (neuroendocrine granules).

CONCLUSIONS

Benign schwannomas may contain rosette-like structures mimicking neuroblastoma/PNET. The techniques used confirmed schwannian differentiation only and eliminated neuroblastoma/PNET. These uncommon variants should be recognised by practising histopathologists to avoid erroneous diagnoses and inappropriate treatment.

Cellular proliferation and nuclear ploidy assessments augment established prognostic factors in predicting malignancy in testicular Leydig cell tumours

AIMS

Testicular Leydig cell tumours are rare. Although most behave benignly approximately 10% are malignant. Clinicopathological features have been described which have some value in predicting malignant behaviour, although as with other endocrine tumours uncertainties remain in many individual cases. Our aim was to determine the clinicopathological features of 20 testicular Leydig cell tumours. We wished to investigate whether, in addition to established clinicopathological features, the MIB1 index and/or flow cytometric analysis of nuclear DNA content are of value in predicting malignancy. We also wished to investigate the frequency of p53 protein accumulation in these neoplasms.

METHODS AND RESULTS

Twenty testicular Leydig cell tumours were studied and the clinical case notes examined. Histological sections were assessed by pathologists involved in the study. Pathological features evaluated included: tumour size, extratesticular extension, nuclear pleomorphism, mitotic activity, necrosis and vascular invasion. Immunohistochemical staining was performed with the anti-p53 monoclonal antibody DO-7 and the cell proliferation marker MIB1. A flow cytometric analysis of nuclear DNA content was also performed. Three tumours behaved in a malignant fashion with the development of metastases. Another had morphological features of malignancy but the patient died a short time after diagnosis from unrelated causes. These four neoplasms were larger than benign tumours, often contained areas of necrosis and sometimes exhibited vascular invasion. They generally exhibited greater nuclear pleomorphism and a higher mitotic rate than benign tumours. Three of the four malignant tumours had a high MIB1 index (20-50%) and the fourth exhibited DNA aneuploidy by flow cytometry. Two malignant tumours showed increased expression of p53 protein, with approximately 50% of nuclei staining with DO-7. All benign tumours had a low MIB1 index (0-2%) and a diploid DNA profile, except for one case where there was DNA aneuploidy. There was little or no staining of benign tumours with DO-7.

CONCLUSIONS

The study confirms that large size, marked nuclear pleomorphism, high mitotic rate, necrosis and vascular invasion are important factors in predicting malignant behaviour in testicular Leydig cell tumours. Additional prognostic value may be derived from the MIB1 index and flow cytometry. Accumulation of p53 protein, through mutational or other events, may be important in malignant progression in these tumours.

Sclerosing epithelioid fibrosarcoma: a study of five cases emphasizing diagnostic criteria

AIMS

To study the clinical and histopathological features of sclerosing epithelioid fibrosarcoma, and to define diagnostic criteria for this uncommon soft-tissue tumour.

METHODS AND RESULTS

Standard histological, immunohistochemical and ultrastructural techniques were applied to five tumours from head and neck, chest wall and groin. Tumours consisted of groups of monomorphic rounded/epithelioid cells surrounded by a prominent collagenous stroma. Tumour cells showed positive vimentin staining but were negative for other markers. They contained prominent rough endoplasmic reticulum and a large Golgi apparatus which in one case was producing collagen secretion granules, an ultrastructural marker for collagen production. Three patients had medium to long-term survival (3-7 years). Of these, one was disease-free for 3 years, and two experienced multiple recurrences: one of the latter died of metastatic disease.

CONCLUSION

Criteria for diagnosing this uncommon tumour include: small to medium cell size, clear or pale cytoplasm, cellular arrangement in cords and strands, dense collagenous stroma; vimentin staining; rough endoplasmic reticulum and a Golgi apparatus producing, in well preserved examples, collagen secretion granules. The paper emphasizes the value of electron microscopy, supporting an appropriate histological picture and immunophenotype, in identifying these relatively low-grade sarcomas.

Histiocytic necrotizing lymphadenitis (Kikuchi-Fujimoto disease): continuing diagnostic difficulties

AIMS

To describe the clinicopathological and immunophenotypic features of 25 cases of Kikuchi-Fujimoto disease (K-F), which remains a poorly recognized entity and is still frequently confused with malignant lymphoma, and to discuss the main diagnostic problems experienced by the referring pathologist.

METHODS AND RESULTS

Haematoxylin and eosin sections of 27 lymph node biopsies were re-examined. Immunostains for B-lymphocytes, T-lymphocytes and macrophages were performed. Clinical and follow-up data were obtained through a questionnaire to the referring pathologist or from the patients' notes where available. The suggested initial diagnoses are discussed. The lymph nodes showed a necrotizing process characterized by patchy or confluent areas of necrosis associated with karyorrhexis and absence or paucity of granulocytes. This was associated with a proliferation of large blastic cells consisting of a mixture of T-lymphocytes and histiocytes. Fragmentation of the biopsy was a frequent feature. The diagnosis of K-F was suggested by the referring pathologist in three cases only. The most common suggested diagnosis was that of a non-Hodgkin's lymphoma.

CONCLUSION

This series documents continuing difficulties in the diagnosis of Kikuchi-Fujimoto disease in the UK and emphasizes that cases are still being mistakenly diagnosed as malignant lymphomas. The diagnosis of Kikuchi-Fujimoto disease merits active consideration in any nodal biopsy showing fragmentation, necrosis and karyorrhexis, especially in young women presenting with cervical lymphadenopathy.

Diagnostic lessons of mucosal melanoma with osteocartilaginous differentiation

AIMS

To document the clinical, morphological and immunohistochemical features of two cases of primary mucosal melanoma with osteocartilaginous differentiation.

MATERIALS AND METHODS

Two cases of mucosal melanoma with cartilage and bone formation are reported, one arising in the vagina of a 79-year-old woman and one in the oral cavity of a 67-year-old man. The vaginal melanoma exhibited only cartilaginous differentiation. The oral cavity mucosal melanoma exhibited both bone and cartilage formation and was remarkable for its multifocality, long history not associated with metastases and its lengthy manifestation of dual morphologies: some of the tumours were typical in situ/invasive melanotic melanomas whilst the others were composed of amelanotic spindle and epithelioid cells with osteocartilaginous tissue. One of the lesions exhibited in situ and invasive melanoma with transition to an osteogenic tumour in places. The patient also developed nonosteogenic malignant melanomas in the nasal cavity and nasopharynx.

CONCLUSIONS

Malignant melanomas showing foci of osteocartilaginous differentiation are extremely rare with only 18 cases reported. Primary mucosal malignant melanomas of vagina and oral cavity showing osteocartilaginous differentiation have not previously been documented. Primary vaginal melanoma with cartilaginous differentiation must be distinguished from primary malignant mixed Müllerian tumour whilst malignant change in a pleomorphic adenoma, sarcomatoid carcinoma, osteogenic sarcoma and mesenchymal chondrosarcoma are included in the differential diagnosis of primary oral mucosal melanomas with osteocartilaginous differentiation. In this context, immunohistochemistry using antibodies to cytokeratin, S100 protein and MIC2 is of value.

Immunohistochemical study of testicular sex cord-stromal tumors, including staining with anti-inhibin antibody

Inhibin is a peptide hormone produced by ovarian granulosa cells and testicular Sertoli cells. Ovarian granulosa cell and other sex cord-stromal tumors usually exhibit positive immunohistochemical staining with antiinhibin antibodies, and this may be valuable in differentiating these neoplasms from histologic mimics. In the present study, we investigated the immunohistochemical staining of testicular sex cord-stromal tumors using antiinhibin. Immunostaining with CAM5.2, vimentin, S-100 protein, desmin, epithelial membrane antigen (EMA), carcinoembryonic antigen (CEA), and placental alkaline phosphatase (PLAP) also was performed because few studies have investigated in detail the immunophenotype of testicular sex cord-stromal tumors. Fifteen of 16 Leydig cell tumors exhibited strong positive staining with antiinhibin. A proportion of Leydig cell tumors also stained positively with CAM5.2 (7 of 16), vimentin (14 of 16), S-100 protein (10 of 16), desmin (2 of 16) and epithelial membrane antigen (4 of 16). Four of six testicular sex cord-stromal tumors with varying degrees of Sertoli or granulosa cell differentiation were positive with antiinhibin, as were two of three sex cord-stromal tumors that were unclassified. Some of these tumors were positive with CAM 5.2, vimentin, S-100 protein, desmin, and epithelial membrane antigen. All tumors were negative with carcinoembryonic antigen and placental alkaline phosphatase. The immunohistochemical findings show that, analogous to their ovarian counterparts, most testicular sex cord-stromal tumors are immunoreactive with antiinhibin. Immunohistochemistry using this antibody as part of a panel may be valuable in confirming a diagnosis of testicular sex cord-stromal tumor and in differentiating these neoplasms from others that may mimic them.