A case of Basaloid Follicular Hamartoma.

We here describe a case of solitary basaloid follicular hamartoma (BFH) : the case developing in company with senile lentigo on the nose. BFH is a relatively rare benign follicular neoplasm of undetermined etiology. Histologically, the specimen consisted of small-sized squamoid or basaloid cells and follicular germ-like cells in the periphery of the tumor nests. There were no infundibular cysts. BFH should be differentiated from infundibulocystic basal cell carcinoma (BCC), which consists of squamoid or basaloid cells in company with infundibular cysts, tumor of follicular infundibulum or trichoepithelioma. We analyzed the immunohistochemical findings of the case in comparison with those of BCC and trichoepithelioma. An immunohistochemical examination revealed 1) that Bcl-2 and CD10 was preferentially expressed in the outermost cells in the tumor nests consisting of follicular germ-like cells, 2) that most of the tumor cells, especially germ-like cells, were strongly positive for Ber-EP4, and 3) that peritumoral stroma was positive for CD34. The immunohistochemical findings of our cases supported that BFH should be differentiated from BCC, a common malignant neoplasm.

Epithelioid hemangioma (angiolymphoid hyperplasia with eosinophilia) in zosteriform distribution.

Epithelioid hemangioma (EH) or angiolymphoid hyperplasia with eosinophilia (ALHE) is an uncommon benign disease. We report an unusual case of EH (ALHE) that arose on the lower back in a zosteriform array. The presence of the characteristic histological appearance of plump endothelial cells with hobnail-like protrusions led to the diagnosis of EH (ALHE). Histological examination of the lesion also revealed the existence of arteriovenous shunts, the possible factor contributing to the pathogenesis of EH (ALHE).

FDG PET/CT findings in acquired perforating dermatosis.

Acquired perforating dermatosis (APD) is an uncommon cutaneous perforating disorder. We report a patient on hemodialysis who developed skin eruption and jaundice. He underwent FDG PET/CT under suspicion of biliary malignancies. PET/CT showed no significant abnormal uptake except of multiple FDG-avid nodules in the skin. The eruption he had was histopathologically diagnosed as APD by skin biopsy. His case suggests that APD should be considered as a differential diagnosis when multiple cutaneous FDG accumulations are found in a patient on hemodialysis. To the best of our knowledge, this is the first report showing the FDG PET/CT findings of APD.

Cutaneous sarcoidosis clinically mimicking necrobiosis lipoidica in a patient with systemic sarcoidosis.

A 70-year-old woman with an 8-year history of systemic sarcoidosis developed round, red-brown eruptions, with central atrophic lesions on her lower legs. The features of the biopsy specimen resembled those of necrobiosis lipoidica (NL), but although necrobiosis was present there were well-formed non-necrotizing granulomas in the dermis. The histological diagnosis was cutaneous sarcoidosis. Systemic sarcoidosis presenting with NL has rarely been reported. The histological features of cutaneous sarcoidosis sometimes mimic those of other granulomatous diseases, including NL and granuloma annulare, which are difficult to distinguish. We discuss the novel association between sarcoidosis and other granulomatous diseases.

Skin tightening effect using fractional laser treatment II: A pilot animal study on skin remodeling.

BACKGROUND: Fractional laser resurfacing is a new procedure for skin rejuvenation. We have found that it has a skin tightening effect in humans. OBJECTIVE: To assess the mechanism of the skin tightening effect of fractional laser treatment in animals using histologic approaches. METHODS: The dorsal skin of hairless guinea pigs was irradiated with a fractional 1,540-nm erbium glass laser. Biopsy specimens were taken serially from 0 hour until 1 year after irradiation and evaluated histologically. RESULTS: Histologic evaluation indicated dermal remodeling within 2 months, in which regenerated collagen bundles and fibroblasts aligned in a horizontal direction, suggesting a traction stress on the dermal components. The treated part became less obvious over a period of more than 3 months by recovery of fine collagen bundles without fibrosis. CONCLUSION: These results suggest that improvement of the tension in a horizontal direction is essential for skin remodeling and improvement of facial laxity using fractional laser resurfacing.

The interaction of inflammatory cells in granuloma faciale.

Granuloma faciale (GF) is a rare chronic inflammatory skin disease characterized by single or multiple reddish-brown cutaneous plaques or nodules. Although this condition is benign, its clinical course is extremely chronic with poor response to therapy. The typical histopathological features of GF include vasculitis with mixed cellular infiltration; however, its etiopathogenesis remains unknown. Here, we describe the case of a 76-year-old man with GF resistant to topical steroids. Biopsy of the lesion revealed i) dense mixed inflammatory cellular infiltrates of lymphocytes, histiocytes, neutrophils, and eosinophils, ii) mild perivascular nuclear dust and swollen endothelium of blood vessels, and iii) a narrow Grenz zone beneath the epidermis. Immunohistochemical staining demonstrated mixed cellular infiltrates intermixed with CD1a(+) dendritic cells, CD68(+) histiocytes, and CD4(+) and CD8(+) T cells.

Desmoplastic fibroblastoma: a case presenting as a protruding nodule in the dermis.

Desmoplastic fibroblastoma is a rare, benign, soft tissue tumor. We describe a case of superficial desmoplastic fibroblastoma presenting as a protruding nodule. A 41-year-old woman presented with a painless, firm, elevated nodule with ulceration on her left thigh. Histological examination from total excision showed a well-circumscribed tumor in the dermis, which comprised of spindle, oval and stellate cells arranged in a haphazard fashion, accompanied by abundant collagenous stroma and inconspicuous vasculature. Immunohistochemically, the tumor cells were positive for vimentin, and focally positive for alpha-smooth muscle actin and muscle-specific actin, but negative for CD34, S-100 protein, desmin and beta-catenin. We diagnosed this case as desmoplastic fibroblastoma arising in the dermis and superficial subcutaneous tissue.