Microreticular perineurioma: A new morphological subtype of a rare entity.

Perineurioma is a benign peripheral nerve sheath tumor. Several subtypes have been described, including plexiform, reticular, and sclerosing. The reticular variant has been previously described as having a net or lace-like growth pattern consisting of large anastomosing cords of spindle-shaped cells. We report a case of an 11-year-old male who presented with a 2-year history of a slowly enlarging, tan-white lesion on the finger. Microscopically, the lesion consisted of cells with ovoid nuclei and delicate, elongate cytoplasmic processes, arranged in a microreticular pattern. The lesional cells were markedly positive for epithelial membrane antigen and claudin-1. Based on these features and the unusual morphology, the case was called a microreticular perineuroma. The patient underwent complete excision of the lesion with no recurrence 9 months after follow-up. To our knowledge, this is the first reported case of this morphologic variant. Awareness of this entity is important to avoid inappropriate management.

A case of indeterminate dendritic cell tumor presenting with leonine facies.

BACKGROUND: Indeterminate dendritic cell tumor is an extremely rare neoplastic proliferation of dendritic cells that share immunophenotypic features of Langerhans cells and macrophages but lack Birbeck granules and Langerin expression. METHODS: We report a 55-year-old female presenting with a leonine facies and generalized multiple confluent papules, nodules and plaques on neck, upper trunk, arms and thighs. Laboratory evaluations were performed including skin biopsies, peripheral blood flow cytometry and positron emission tomography-computed tomography. RESULTS: The lesional skin biopsy showed a dense dermal and perifollicular infiltrate composed of histiocytoid cells with nuclear grooves lacking dendritic processes in a background of lymphocytes. Eosinophils were absent. The histiocytoid cells were CD68+CD1a+Langerin- and only focally S100+. Special stains including GMS, Gram and Fite were all negative for infectious organisms. Although an initial diagnosis suggesting Langerhans cell histiocytosis was proposed due to CD1a positivity, a diagnosis of indeterminate dendritic cell tumor was finally rendered based on the histopathological findings and the lack of expression of Langerin. CONCLUSION: This case illustrates the variegated clinical presentation of indeterminate cell tumor and the necessity of appropriate immunohistochemical workup for its diagnosis.

Prostate carcinoma, presenting with a solitary osteolytic bone lesion to the right hip.

Prostate cancer is the most common malignancy and the second most common cause of cancer-associated mortality in males. Bone metastasis is frequent and generally multiple and osteoblastic. Presentation of a pure osteolytic and solitary metastasis from a prostate carcinoma is extremely rare. We report a case of prostate cancer in a 70-year-old man who presented with progressive severe right hip pain and stiffness with no urinary symptom. A whole-body bone scan revealed a solitary metastasis to the right hip. A prostate biopsy revealed prostate adenocarcinoma. We believe this is the first reported case of presentation of a solitary osteolytic bone metastasis in the pelvis from carcinoma of the prostate.

2.45 GHz radiofrequency fields alter gene expression in cultured human cells.

The biological effect of radiofrequency (RF) fields remains controversial. We address this issue by examining whether RF fields can cause changes in gene expression. We used the pulsed RF fields at a frequency of 2.45 GHz that is commonly used in telecommunication to expose cultured human HL-60 cells. We used the serial analysis of gene expression (SAGE) method to measure the RF effect on gene expression at the genome level. We observed that 221 genes altered their expression after a 2-h exposure. The number of affected genes increased to 759 after a 6-h exposure. Functional classification of the affected genes reveals that apoptosis-related genes were among the upregulated ones and the cell cycle genes among the downregulated ones. We observed no significant increase in the expression of heat shock genes. These results indicate that the RF fields at 2.45 GHz can alter gene expression in cultured human cells through non-thermal mechanism.