Nanako Yamada

Scedosporium apiospermum skin infection: A case report and review of the literature

Scedosporium apiospermum (the anamorph of Pseudallescheria boydii) is a ubiquitous soilinhabiting fungus that can cause human infection after traumatic subcutaneous implantation or inhalation.1 Recently, it has been shown to infect both normal and immunosuppressed patients. In the latter S apiospermum can cause invasive disease and spread hematogenously to produce endophthalmitis, endocarditis, and metastatic abscesses.2,3 Fungal soft tissue infections are common in developing countries in which fungal elements in soil and vegetation may become implanted in the skin, particularly when farmers work barefoot.4 We describe a case of S apiospermum infection of the right hand in a patient who was receiving long-term prednisolone therapy for polymyositis.

In vivo effect of industrial titanium dioxide nanoparticles experimentally exposed to hairless rat skin

Abstract We morphologically investigated animal skin exposed to W/O emulsion containing 10 wt % ultrafine TiO2 particles that had been characterized. After 4 h, exposed skin was investigated by light microscopy, confocal laser scanning microscopy (CLSM) and electron microscopy with energy-dispersive X-ray spectrometry (EDX). Light microscopic evaluation was also performed on the exposed skin after 24, 72 and 168 h. Light microscopy did not show any morphological and immunohistochemical changes in the skin. Electron microscopy revealed that the most TiO2 particles were localized in the interfollicular stratum disjunctum and the keratinized layer of follicular infundibulum. No TiO2 particles were detected in the viable skin, which was confirmed by EDX. Furthermore, we demonstrated a specific TiO2 affinity to the follicular opening area by light microscopy and low-vacuum scanning electron microscopy with EDX. Our study suggests that TiO2 particles neither penetrate into viable cell layers nor biologically cause any cellular changes.

Subchronic exposure of titanium dioxide nanoparticles to hairless rat skin

The evaluation of the biological effects of industrial nanoparticles on the skin is necessary for their risk assessment. To clarify the influence of TiO2 nanoparticles on the skin, we carried out a subchronic exposure study of TiO2 nanoparticles to hairless rat skin. W/O emulsion containing 10 wt% TiO2 nanoparticles and control emulsion was applied to the dorsal skin of Hairless Wistar Yagi rats once a day for a maximum period of 56 consecutive days. After 2, 4 and 8 weeks, skin samples were taken from the exposed skin area. Histopathologically, the particles were only located in the stratum corneum layer of epidermis and follicular epithelium. Focal parakeratosis and spongiosis were observed in the epidermis. Transmission electron microscopy with energy‐dispersive X‐ray spectrometry (EDX) analysis failed to show TiO2 nanoparticles in the viable skin areas. There was no evidence of TiO2 penetration in the viable skin areas. In addition, titanium contents in several organs were determined using inductively coupled plasma mass spectroscopy. Increased titanium concentration was detected in lung samples of the TiO2 emulsion‐treated groups after 8 weeks. It was most likely that the presence of TiO2 in the lungs was not caused by direct absorption of nanoparticles from the skin but was due to rats inhaling the nanoparticle. We did not find any obvious evidences of nano‐TiO2 particle skin penetration using several morphological methods after the subchronic exposure. We believe that the influence of subchronic exposure of TiO2 is not significant based on our study.

Intralymphatic histiocytosis with granuloma formation associated with orthopaedic metal implants.

A 75‐year‐old man presented with a 1‐year history of asymptomatic reddish‐brown nodules on his left knee, in which orthopaedic metal implants had been inserted for a transformation‐related knee joint disorder. Histopathological examination revealed typical features of mixed cell granuloma with many dilated lymphatics that contained many histiocytes from the upper dermis to subcutaneous fat tissue. Results of qualitative analysis of biopsy specimens by energy‐dispersive X‐ray spectroscopy were positive for molybdenum, which was one of the constituents of the metal implant. We describe the first observation of intralymphatic histiocytosis with granuloma formation in the skin occurring in a patient bearing orthopaedic metal implants for a transformation‐related knee joint disorder.

A case of cutaneous protothecosis successfully treated with local thermal therapy as an adjunct to itraconazole therapy in an immunocompromised host

We report a case of human protothecosis in an immunocompromised host which was caused by Prototheca wickerhamii and was successfully treated with thermal adjunct therapy combined with systemic itraconazole therapy. A 78-year-old man taking 30 mg prednisolone daily had a 1-week history of erythematous plaques on the dorsal aspect of his right hand and forearm after sustaining a small traumatic injury. Histopathology of the lesions revealed granulomatous inflammatory changes with numerous microorganisms that had multiple septations in their cytoplasm. On the basis of mycological features and the results of the sugar assimilation test, the etiologic agent was identified as Prototheca wickerhamii. Although the lesion showed no response to the systemic itraconazole therapy and topical ketoconazole treatment, a complete resolution was achieved by the use of thermal therapy as an adjunct to systemic itraconazole.

A morphological study of granulomas induced by subcutaneous injection of leuprorelin acetate

Leuprorelin acetate‐induced granulomas in subcutaneous injection sites have been occasionally reported, but there have been no detailed morphological examinations. Histopathology of leuprorelin acetate‐induced granulomas in six patients was studied, and one of them was evaluated by electron microscopy. Study using haematoxylin and eosin staining revealed that there were many intracytoplasmic vacuoles in the granulomas and degeneration of fat tissue. Ultrastructurally, electron‐lucent spherical bodies (microcapsules of leuprorelin acetate products) were observed in the granuloma cells. Needle‐shaped crystalloid structures in lipid droplets (degenerated lipid droplets) were observed in the granuloma cells and fat tissue. Degeneration of fat tissues caused by leuprorelin acetate is one of main factors responsible for granuloma formation.

Myofibroblastic differentiation in atypical fibroxanthomas occurring on sun-exposed skin and in a burn scar: an ultrastructural and immunohistochemical study

Herein, we report the investigation of two cases of atypical fibroxanthoma (AFX). One AFX developed within actinically damaged skin, as is typical, while the other developed within a burn scar within non‐sun‐exposed skin. The two tumors showed almost identical histopathological, immunohistochemical and ultrastructural features. The tumors were composed of pleomorphic spindled, epithelioid, multinucleated and bizarre cells with enlarged atypical nuclei. Most tumor cells expressed vimentin and about 50% expressed CD10. Some tumor cells also expressed α‐smooth muscle actin and CD68. However, there was no expression of cytokeratins, p63, S‐100 protein, melan‐A, HMB 45, desmin, epithelial membrane antigen or CD34. Ultrastructurally, the tumor cells contained myofilaments with dense patches but lacked plasmalemmal caveolae and basal lamina. The most prominent finding was the identification of fibronexus junctions. In addition, there were tumor cells containing numerous lysosomal granules. In conclusion, we clearly showed myofibroblastic differentiation in AFX by electron microscopy. We report also a case of AFX directly developing within a burn scar in the absence of actinic damage.

Abnormal cell attachment in circumscribed palmar hypokeratosis: ultrastructural observations

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Solitary sclerotic fibroma of the skin : morphological characterization of the 'plywood-like pattern'

Sclerotic fibroma is an uncommon skin tumor. Rapini and Golitz reported 11 cases of solitary sclerotic fibromas in patients without Cowden’s disease in 1989. We report a case of sclerotic fibroma that presented as an asymptomatic nodule in a 34‐year‐old Japanese man. Histopathological examination revealed typical features of sclerotic fibroma of the skin. Ultrastructural examination showed that spindle cells with myoid features had proliferated around the vasculature. They had segregated from the perivascular area by leaving the surrounding basal lamina, resulting in their phenotypical change to produce collagen accumulating in a concentrically lamellar fashion. We suggest a possible role of abnormal blood vessels and surrounding specific cells in the development of sclerotic fibroma.

Solitary sclerotic neurofibroma of the skin.

Solitary neurofibroma of the skin is a benign soft tissue tumor. Clinically, it is a flesh-colored, slow-growing, soft tumor and sometimes shows diverse histological patterns. We present here a case of nontender, hard neurofibroma with sclerotic change. By transmission electron microscopic observation, some mast cells in close contact with fibroblasts and abundant collagen fibers were seen in the lesion. Our findings suggest that mast cells may have played a role in the formation of the sclerotic regions of the current tumor.