Motoyuki Mihara

Cutaneous nerves in atopic dermatitis

Abstract Although pruritus is the cardinal symptom of atopic dermatitis, its mechanism is not well understood. Free nerve endings in the skin are involved in pruritus as itching receptors. We studied the cutaneous nerve fibres in lichenified lesions of 16 patients with adult atopic dermatitis. On immunohistochemistry, fibres immunoreactive for neurofilament, neuron-specific enolase, and protein gene product 9.5 were observed in the papillary dermis and dermoepidermal junctions as well as in the epidermis. In these areas, no fibres stained positively for substance P, neuropeptide Y, vasoactive intestinal peptide, beta endorphin, somatostatin or serotonin. On electron microscopy, the ultrastructure of subepidermal and intraepidermal free nerve endings appeared to be essentially normal. However, the distribution density of the cutaneous nerve fibres was much higher than in normal controls, and the diameter of these fibres was much larger, because of the large number of axons in each nerve fibre. Degranulation of mast cells was not seen. These findings suggest that pruritus in lichenified atopic skin is probably not caused by damage to the cutaneous free nerve endings. In such lesions, the number of the cutaneous free nerve endings is greatly increased, but they may have a normal function.

Acquired tufted angioma showing spontaneous regression

We report a 62‐year‐old woman with acquired tufted angioma. Several scattered reddish nodules were present on the neck and upper chest. During a follow‐up period of 6 months, some of the lesions showed transient spontaneous regression and one disappeared completely. Electron microscopy revealed that a few tumour cells contained Weibel‐Palade bodies in their cytoplasm.

Lichen sclerosus et atrophicus. A histological, immunohistochemical and electron microscopic study

We studied three cases of genital lichen sclerosus et atrophicus (LSA) using histological, immunohistochemical and ultrastructural techniques to elucidate the characteristics of the collagen fibres, the elastic fibres and the interfilamentous matrix in the upper dermal homogeneous zone. In the early stages of LSA, the homogeneous zone caused elaunin fibres to push downwards and partially disappear, the collagen fibres were presumably phagocytosed by fibroblasts, and there were peculiar cells containing numerous vacuoles in the cytoplasm. In the advanced stages of LSA, the homogeneous zones showed newly formed collagen fibres and amorphous, dispersed, medium electron-dense substances that were probably composed of elastin or elastin-like substances and microfilaments originating from the collagen fibres. Immunohistochemically, there were numerous anti-aortic alpha-elastin-positive substances, but there was no positivity for anti-amyloid P component. These findings suggest that in advanced LSA a hybrid substance (elastocollagenous mass) between collagen fibres and elastic fibres may be formed in the homogeneous zone.

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.

Febrile ulceronecrotic Mucha–Habermann disease: a case report and a review of the literature

This report describes the case of a 76 year old man who suffered from febrile ulceronecrotic Mucha–Habermann disease (FUMHD). Despite this patient’s typical clinical and histological findings, the fulminating course led to death. Polymerase chain reaction (PCR) analysis of the skin lesions showed that the infiltrating cells were monoclonal in origin and were from an aberrant clone. FUMHD is a very rare, febrile variant type of pityriasis lichenoides et varioliformis acuta, and is characterised by necrotic cutaneous ulcerations associated with high fever and systemic manifestations. Including this present case, only 18 cases of FUMHD have been reported. FUMHD can occur in both adults and children, although there are several differences between the manifestations of the disease in the two groups. One major difference is prognosis: all cases resulting in fatality are of the adult type, whereas no fatal cases have been reported among children. The aberrant clone detected by PCR may be responsible for host responses, resulting in the severe symptoms observed in this disorder.

Cutaneous focal mucinosis

A 39‐year‐old man had typical cutaneous focal mucinosis on the left forearm. The fibroblasts in the myxomatous lesion had many cytoplasmic vesicles, and on electron microscopy, these were compatible with condensing vacuoles or secretory granules. The fibroblasts in this case were considered to be mucoblasts involved in the over‐production of the ground substance, that was mainly composed of hyaluronic acid.

Microcystic Adnexal Carcinoma

We present a patient with microcystic adnexal carcinoma. The lesion was an indurated plaque on the skin of the right upper lip of a 58-year-old woman which was slowly growing during 27 years. Carcinoembryonic antigen was immunoreactive in the luminal contents of the tumor ducts and in the cytoplasm of cells surrounding ducts. S-100 protein was positive in the cytoplasm of a few cells at the lower dermis. These observations suggested that this tumor was related to sweat glands. Furthermore, electron microscopy revealed that tumor cells had features of eccrine ductal cells. These observations confirm that this tumor appeared at least capable of eccrine duct differentiation.

Primary Cutaneous Meningioma on the Scalp: Report of Two Siblings

Primary cutaneous meningioma (PCM) is a rare tumor whose pathogenesis is quite obscure. We reported PCMs occurring on almost the same occipital region of two siblings studied by histology, immunohistochemistry, and electron microscopy. Both lesions were attached to duras, but extracranial. One lesion was histologically diagnosed as meningothelial meningioma; its tumor cells showed electron microscopically interdigitating cytoplasmic processes with junctional complexes. The other was interpreted as fibroblastic meningioma; its tumor cells were arranged linearly in a stepping‐stone arrangement and had small dense bodies in the cytoplasm. The tumor cells stained positively with anti‐vimentin antibody. Both lesions had adenomatous hyperplasia of the eccrine glands. Although the histologic and electron microscopic features of these two lesions slightly differed from each other, their pathogenesis was essentially considered to be acoelic or rudimentary meningocele.

Acral pseudolymphomatous angiokeratoma of children: immunohistochemical and clonal analyses of the infiltrating cells

Background:  Acral pseudolymphomatous angiokeratoma of children (APACHE) is a disorder characterized clinically by red nodules and histopathologically by a massive subepidermal lymphohistiocytic infiltrate. Although it was initially thought to be a vascular nevus, it has never been regarded as a pseudolymphoma.

Distribution Density of Intraepidermal Nerve Fibers in Normal Human Skin

A total of 74 specimens was obtained from the normal human skin of patients from 3 to 90 years old. The specimens were roughly classified into 5 groups: 15 for the face group from the face; 15 for the abdomen group from the abdomen; 13 for the back group from the back; 14 for the arm group from the upper arm and forearm; and 17 for the leg group from the thigh and lower leg. They were all fixed in 4% paraformaldehyde and 14% saturated picric acid. Cryostat sections were examined by the immunoperoxidase method and indirect immunofluorescence (IF). Primary antibodies against neurofilament, neuron‐specific enolase, protein gene product 9.5 (PGP 9.5) and S‐100 protein were used. The most effective method was found to be the combination of IF with PGP 9.5; it visualized the intraepidermal nerve fibers easily and clearly. Of the 74 specimens, 32 (43%) had intraepidermal PGP 9.5‐immunoreactive (or nerve) fibers (IPIF), and 42 (57%) did not have any. With reference to the different skin locations, the maximal rate of specimens having IPIF was 57% in the arm group, and the minimum was 23% in the back group. IPIF positive specimens had approximate surface lengths of 6 mm, in which the existence number of the IPIF was 1 to 75. Their distribution density per 1000 epidermal basal cells was highest at 9.63 in the arm group and lowest at 2.89 in the back group. Their thickness was 2.94 ± 0.83 μm with no significant differences among the five groups. We concluded that intraepidermal nerve fibers may not be distributed evenly in the hairy portions of normal human skin, but they may be present focally. Physiologically, two‐point discrimination of itch may be explained by the distribution mode of intraepidermal nerve fibers.