Folliculosebaceous smooth muscle hamartoma.

Cutaneous hamartomas are a group of heterogenous benign skin conditions demonstrating epithelial and mesenchymal components in varying proportions. Folliculosebaceous (cystic) hamartomas comprise a distinct group of uncommon cutaneous tumor-like malformations. Histologically, these lesions demonstrate varying proportions of adnexal and stromal tissues. We review the literature on folliculosebaceous hamartoma and report a case with smooth muscle as its only stromal component.

Case report: Nocardia asteroides mycetoma.

Primary cutaneous infections with Nocardia asteroides are rare and have been reported in immunocompromised patients. Herein, we report a case of primary cutaneous Nocardia asteroides mycetoma of the skin in an immunocompetent individual. The infection was treated successfully with trimethoprim-sulfamethoxazole. Because a prolonged incubation time is required for the cultures and since additional biochemical tests are necessary for identification of this species, the clinician should alert the microbiology laboratory when such an infection is suspected clinically.

Multifocal papillary apocrine adenoma arising in a systematized linear epidermal nevus.

Previous reports indicate that a linear epidermal nevus (LEN) may serve as a source of development for additional skin tumors. We report an unusual case of multifocal papillary apocrine adenoma (PAA) arising in an LEN. This is the first case of its kind documented in the literature.

Eosinophilic intranuclear inclusion bodies in a melanocytic nevus.

We report a case of eosinophilic or hyaline true intranuclear inclusion bodies in a melanocytic nevus. Although intranuclear pseudoinclusions are frequently found in melanocytic nevi, true intranuclear inclusions are rare. The true intranuclear nature of the inclusions in our case was confirmed with ultrastructural examination. With reverse transcriptase in situ polymerase chain reaction (RT in situ PCR) analysis, eosinophilic bodies stained positive for molluscum-specific primers. This result suggests that such inclusions may be related to molluscum viral infection of melanocytes.

Complex adnexal tumours of the skin: a report of three cases and review of literature.

AIMS: Complex or composite adnexal tumours of the skin (CATS) are unusual neoplasms composed of two or more histopathologically distinct subtypes of appendageal neoplasms coexisting in a single cutaneous lesion. The authors report three examples of CATS, review literature and discuss their probable histogenesis. METHODS AND RESULTS: Of the three tumours described, one tumour showed a mixture of a proliferating pilar tumour and syringocystadenoma papilliferum, the second lesion was composed of a proliferating pilar tumour and tubulopapillary hidradenoma and the third tumour exhibited a syringocystadenoma papilliferum and tubulopapillary hidradenoma in combination. CONCLUSIONS: CATS are rare tumours. The authors reported three unique cases in addition to the 10 other reported cases. These three cases further strengthen the hypothesis of a 'folliculosebaceous apocrine' unit as the most likely point of origin of CATS.

Primary cutaneous adenomyoepithelioma.

Adenomyoepitheliomas are biphasic tumors composed of epithelial and myoepithelial components in varying proportions. They are commonly reported in the breast, uncommonly in salivary glands, and rarely in the lungs and vulva. Recent molecular analysis has shown that p27/kip-1 protein may play a role in their development. Primary cutaneous adenomyoepithelioma is an extremely rare tumor with only three well documented cases reported to date. We report a case of primary cutaneous adenomyoepithelioma with histological and immunohistochemical characterization, and discuss their differential diagnosis, biologic behavior and treatment strategies.