Tae Inoue

Spontaneous regression of Merkel cell carcinoma: a comparative study of TUNEL index and tumor-infiltrating lymphocytes between spontaneous regression and non-regression group

Some Merkel cell carcinomas (MCC) have been reported to regress spontaneously. To clarify the mechanisms of spontaneous regression (SR) of MCC, we analyzed the TUNEL index, the labeling index of proliferating cell nuclear antigen (PCNA), the labeling index of bcl-2 protein, and the expression of p53 of the tumor cells. We also evaluated the number of infiltrating lymphocytes surrounding the tumor in the tissue specimens. Among seven patients with MCC (SR: n=4; non-regression (NR): n=3), the TUNEL index in the SR group was significantly higher than that in NR group (5.2 and 2.0%, respectively). In addition, the number of lymphocytes around the tumor nests was also significantly increased in the SR group compared to NR group (1576 and 663 cells/mm(2), respectively). Most of the infiltrating lymphocytes were UCHL-1 positive T-cells. There were no significant differences of the PCNA labeling index, the bcl-2 protein labeling index, and the expression p53 between SR and NR group. These results indicate that apoptosis and local T-cell mediated immune response might be involved in spontaneous regression of MCC.

Activation of mast cells within a tumor of angiosarcoma: ultrastructural study of five cases.

The accumulation of mast cells around tumors is a well‐recognized phenomenon in a number of malignancies, including basal cell carcinoma, melanoma, and breast cancer. However, little information exists regarding mast cells within tumor nests. To clarify the role of mast cells infiltrating in skin cancers, we examined the morphological features of mast cells within tumors of five cases of angiosarcoma, including two patients with Stewart‐Treves syndrome, by electron microscopy. In light microscopy, mast cells were observed within tumor nests at various densities and exhibited weak staining intensity with toluidine blue. By electron microscopy, most of the tumor‐infiltrating mast cells exhibited anaphylactic or piecemeal degranulation, indicating that the mast cells had been activated in situ. Some mast cells were noted in close apposition to tumor cells, suggesting the existence of direct cell‐to‐cell interactions. Tumor cells adjacent to mast cells showed no degenerative changes. In conclusion, these results suggest that careful histologic examination in combination with electron microscopy should enable us to identify more mast cells within cancer lesions with greater sensitivity than in a number of prior reports. Furthermore, the close proximity of mast cells and surrounding tumor cells suggests some biologically significant role of mast cells in the development of angiosarcoma, including tumor growth as well as host immunity and stromal reaction.

Alteration of mast cell proliferation/apoptosis and expression of stem cell factor in the regression of mastocytoma – report of a case and a serial immunohistochemical study

Background: Spontaneous regression of solitary mastocytoma is a well‐described phenomenon, but its mechanism is unknown.

A Case of Otomycosis Caused by Aspergillus sclerotiorum

To the Editor: Otomycosis is a fungal infection of the external auditory canal, that is more common in tropical and subtropical areas that experience long periods of high atmospheric humidity. Predisposing factors to fungal infection include habitual instrumentation, dermatitis, and immunocompromising conditions. Otomycosis is frequently encountered in a post-operative cavity such as that after a radical mastoidectomy. Excessive accumulation of cerumen in the cavity is believed to provide favorable conditions for the saprophytic growth of fungi. The most common fungal species involved are Aspergillus niger, A. fumigatus, A. flavus, Candida, and Penicillium. We report a case of otomycosis caused by a fungal species that has never been previously identified as a pathogen. A 46-year-old Japanese man visited our department in June of 2001 with deep-seated itching and discharge from his right ear. He had undergone a radical mastoidectomy for a cholesteatoma of his right middle ear 15 years previously. He had been treated for the presenting complaints with topical bifonazole for the past three years. Endoscopy of the right ear canal revealed a whitish, fluffy, cotton-like material together with keratinous debris and an exudate. We inoculated the debris onto malt extract agar medium, and observed the growth of yellow fungal colonies with a loose surface, dark yellow conidia, pale yellow conidial heads, and yellow sclerotia (Fig. 1). Direct microscopy of the cultured fungi revealed radiating conidial heads, light brown conidiophores about 700 μm long and 7 μm in diameter, globose vesicles, about 24 μm in diameter, sterigmata in two series, approximately about 10 μm long, and secondaries about 6 μm long, with smooth globose conidia about 2.5–3.0 μm in diameter (Fig. 2). We identified the culture as A. sclerotiorum. The patient was prescribed itraconazole orally (100 mg/day) for 14 days, but he failed to return for follow up. The A. ochraceus group consist of nine Fig. 2. Shown are radiating conidial heads (a), with light brown conidiophores (b), globose vesicles (c), sterigmata in two series (d), with globose conidia, about 2.5–3.0 μm diameter (e). The Journal of Dermatology Vol. 31: 949–950, 2004

Case of malignant schwannoma complicated by Recklinghausen disease.

We report a case of 59-year-old male with malignant schwannoma of the back associated with von Recklinghausens disease.In 1995, the first surgical resection was performed. The tumor was diagnosed as cutaneus neurofibroma. But in 1997, the tumor rapidly recurred and the second resection was performed. The histopathological findings were consistent with malignant schwannoma. Six months after the second resection, he has no evidence of recurrence or metastasis.