The mineralization and biodegradation of cerebrospinal fluid shunting systems were studied using material from 25 shunts that had been implanted for between 6 days and 10 years. New unused materials were also examined for comparison. Surface changes in six systems could be observed under an operating microscope. Substantial quantities of a white deposit had adhered to the tubing in four of the shunts. These changes were most advanced in the galeal penetrative portion of the shunts and are believed to have been caused by mechanical stress. Scanning electron microscopic analysis revealed surface wrinkles, microscopic holes, and tiny particles, suggesting deterioration of the material itself. An energy-dispersive analysis using x-rays demonstrated that the surface deposits were due to mineralization of calcium phosphate and that the tiny particle growth was aluminum. These changes may be a consequence of the degradation of silicone rubber. A discriminant analysis of the mineralization was carried out; thus, the age of the host and the duration of system implantation could be correlated with the incidence of mineralization (p less than 0.1). A measurement of the physical properties showed progressive change with a remarkable deterioration in systems implanted for more than 5 years.

In 1980, Rothko, Farmer, and Zeligman first described the disease entity "Superficial epithelioma with sebaceous differentiation" as a histologically distinct, rare, benign lesion. We report here the first Japanese case fitting this description. The patient is a 38-year-old Japanese woman, who had a small, yellow, flat-topped, well-defined plaque on her right upper eyelid. Histologically, the lesion was a multilobular, superficial, dermal tumor with numerous broad attachments to the overlying epidermis. The overall configuration was a plate-like proliferation of tumor cells with well-defined borders. The tumor cells were basically uniform basaloid cells with single or clustered sebocytes in the upper part of the tumor and multiple well differentiated sebaceous lobules in the middle and lower parts of the tumor. Multiple cystic spaces were formed in the lobules. Differential diagnosis of several tumors with sebaceous differentiation is discussed.

To compare the histological features of non-drug-induced and drug-induced coma blister, we performed histopathological and immunopathological studies of four biopsy specimens from three patients with non-drug-induced coma. These results were compared with the previously well-documented histology of drug-induced coma. The findings of the present study of non-drug-induced coma included (a) a variable degree of epidermal cell degeneration, including vacuolation of basal cells, intraepidermal blister formation with pale cytoplasm, and extensive coagulation necrosis with pale nuclei; (b) alteration of the outer root sheath of telogen follicles, ranging from focal necrosis to total coagulation necrosis, and degeneration of sebaceous gland with disappearance of the germinative cell layer; (c) secretory eccrine cells with pyknotic nuclei, vacuolation of the cytoplasm, and intercellular edema, resulting in poorly defined cytoplasm, although the nuclei of the outer basal layer were partially preserved; (d) from slight edema of the vessel wall of the venules to fibrinoid, thrombosis and/or fibrinoid necrotic degeneration of arterioles and venules; and (e) deposits of immunoglobulins or complement as detected by direct immunofluorescent technique in all the three cases. One significant difference between non-drug-induced and drug-induced coma blister was the presence of fibrinoid thrombi in the lumina of non-drug-induced coma blisters. Since one of the three cases of non-drug-induced coma studied in the present report did not show thrombi in the lumina, this feature may not always be available for the differential diagnosis of these two conditions. However, fibrinoid thrombi may be a good marker for the differentiation of these two conditions, when the depth and duration of non-drug-induced coma are severe enough to induce these lesions.

We report a 39-year-old Japanese woman with a 30 x 10 mm, skin-colored, soft, hairless, irregularly elevated plaque in the left retroauricular area. Histologically, it consistently showed features of atypical hair follicles; some showed immaturely developed basaloid epithelial islands invaginated with condensed stromal cells, and others were replaced or associated with solid strands, branching cords, or lace-like networks of undifferentiated basaloid cells. Although the clinical appearance of a typical localized basaloid follicular hamartoma is a plaque of alopecia, this case seems to be a variant, because the histological findings are so characteristic of the entity. The relationship of basaloid follicular hamartoma to other hair-follicle derived tumors is also considered.

HPV-associated epidermal cysts of the sole (HAECS) of the foot have been reported recently in Japan in which there is positive staining for papillomavirus antibody in the nuclei of the epithelial cells in the cyst wall and vacuoles in the stratified horny material inside the cysts. A causative association with a newly recognized HPV, HPV 60, has been recorded. The authors report two new cases. The possible mechanism of cyst formation in HPV 60-infected epithelium is discussed.