Hiroshi Hanyaku

Solitary cutaneous malignant schwannoma : immunohistochemical and ultrastructural studies

We describe two cases of malignant schwannoma in the skin that did not originate from a nerve trunk and was not associated with neurofibromatosis. Light microscopy showed that both tumors were composed predominantly of atypical spindle-shaped cells. Immunohistochemical analysis was performed with various monoclonal antibodies against mesenchymal determinants. In both patients, tumor cells were positive for S-100 alpha and S-100 beta, neuron-specific enolase, vimentin, neurofilament protein, and myelin basic protein, and negative for HMB-45, glial fibrillary acidic protein, epithelial membrane antigen, and desmin. Electron microscopy revealed that the tumor cells possessed indented nuclei with an electron-lucent cytoplasm. Immunoelectron microscopy showed diffuse fine granular staining for S-100 alpha, not detectable in normal Schwann cells, in the cytoplasm of the tumor cells.

Metastatic testicular choriocarcinoma of the skin. Report and review of the literature.

Choriocarcinoma is a malignant growth of trophoblastic cells characterized by secretion of human chorionic gonadotropin. Choriocarcinoma usually arises from fetal trophoblasts and rarely arises from germ cells in the testis or ovary or derives from dedifferentiation of other carcinomas. Skin metastasis of choriocarcinoma is rare: only seven cases have been reported in the English and Japanese literature. We report the case of a 22-year-old Japanese man with pure choriocarcinoma of the testis who developed skin metastases that presented as multiple reddish nodules. Microscopic examination of both the primary lesion of the testis and the cutaneous metastasis demonstrated the typical histologic features of pure choriocarcinoma. The patient died 3 months after the initial onset of skin metastasis. Review of the literature indicates that skin metastasis of choriocarcinoma usually occurs as a nodular lesion with the histologically typical feature of the primary disease and signals of poor prognosis.

Is cutaneous plasmacytosis a distinct clinical entity

We describe a Japanese patient with cutaneous plasmacytosis whose clinical course we observed for 5 years. We also review 26 patients with this condition, including 24 Japanese and two non-Japanese, reported in detail. This review revealed that this condition has characteristic clinical and pathologic features and should be considered a distinct clinical entity. The reason for the predominant occurrence of cutaneous plasmacytosis in Japanese patients is unknown.

Application of neutral red staining for evaluation of the viability of dermatophytes and Candida in human skin scales

The fungal elements observed by direct microscopic examination sometimes fail to grow on subsequent culture. To elucidate the cause of this discrepancy, the viability of dermatophytes and Candida in skin scales was evaluated by neutral red staining. Autoradiographic study using 3H-thymidine confirmed that grain-positive cells (viable cells) were stained with neutral red, whereas negative cells (non-viable cells) were not stained. Taking this as a baseline, the correlation between neutral red-positive fungal elements in scales taken from 211 patients with tinea and 27 patients with cutaneous candidosis and cultures on Sabouraud glucose agar was studied. Strong positive correlations were found in both mycoses. These findings suggest that neutral red staining provides a useful method for evaluating the viability of dermatophytes and Candida in human skin scales.

A case of bullous pemphigoid with antidesmoplakin autoantibodies

Paraneoplastic pemphigus, a recently identified disease entity, is associated with autoantibodies against a variety of epidermal proteins including desmoplakins I and II, and the 230‐kDa bullous pemphigoid (BP) antigen. We report an 84‐year‐old Japanese man who had typical clinical and histopathological features of BP, but in whom indirect immunofluorescence, using normal human skin as the substrate, revealed concomitant serum antibasement membrane zone and antikeratinocyte cell surface autoantibodies. His serum showed reactivity similar to that which is seen with antidesmoplakin monoclonal antibody on immunofluorescence of cardiac muscle and urinary bladder. With immunoblotting, using various antigen sources, the patients serum reacted with desmoplakins I and II. and with both the 230‐ and 180‐kDa BP antigens. Immunogold electron microscopy also indicated the presence of antidesmoplakin antibodies. Although the significance of the antidesmoplakin antibodies in this patient is unknown, the findings in this case may provide an insight into understanding the occurrence of antidesmoplakin antibodies in paraneoplastic pemphigus.

Immunohistochemical Study of Mixed Tumor of the Skin with Marked Ossification

We observed an unusual case of mixed tumor of the skin associated with marked ossification on the upper lip of a 68-year-old Japanese woman. The tumor was a well-circumscribed mass that measured 3 x 3 x 2 cm and contained exuberant bone formation with a marrow-like structure. Histological examination of the tumor showed that the bones occupied a quarter of the specimen. Except for the large bone formation, the tumor showed typical features of a tubulocystic type of mixed tumor. The bone was formed without intervening cartilage, suggesting the possibility of the direct deposition of osteoid by metaplastic cells. To our knowledge, no similar case of mixed tumor of the skin associated with marked bone formation has been reported.

Differential expression of the 45 kDa protein (actin) during the dimorphic transition of Sporothrix schenckii

We investigated the gene expression of a protein during the dimorphic transition from yeast to mycelial form of Sporothrix schenckii. Yeast cells were converted to mycelial cells in Sabouraud glucose broth at 25 degrees C. After 1, 3 and 5 days of culture, the intermediate form of cells between yeast and mycelium was obtained, and after 7 days these cells were morphologically similar to the mycelial cells. Proteins having the molecular weight of 45 kDa were found to by synthesized preferentially by intermediate form of day 7 and mycelial cells. On the other hand, the 45 kDa proteins were predominantly translated by the RNA isolated from the intermediate of day 7 and mycelial cells using in vitro cell-free translation assay. The 45 kDa proteins synthesized by mycelial cells were found to be identical with the 45 kDa translation products directed by the mRNA isolated from the intermediate and mycelial cells by V8 protease peptide mapping. The 45 kDa protein was considered to be actin by Western blot analysis using an anti-actin monoclonal antibody. These results suggest that the intermediate form of day 7 has the same phenotypes in the morphology and biosynthesis of actin as those of mycelial cells. The expression of the actin gene may be involved in the dimorphic transition of S. schenckii.