CD10, p63 and CD99 expression in the differential diagnosis of atypical fibroxanthoma, spindle cell squamous cell carcinoma and desmoplastic melanoma

p63 is an alternative p53 repressor in melanoma that confers chemoresistance and a poor prognosis

p63 is up-regulated in melanoma and prevents nuclear accumulation of p53.

The role of apoptosis in melanoma pathogenesis and chemoresistance is poorly characterized. Mutations in TP53 occur infrequently, yet the TP53 apoptotic pathway is often abrogated. This may result from alterations in TP53 family members, including the TP53 homologue TP63. Here we demonstrate that TP63 has an antiapoptotic role in melanoma and is responsible for mediating chemoresistance. Although p63 was not expressed in primary melanocytes, up-regulation of p63 mRNA and protein was observed in melanoma cell lines and clinical samples, providing the first evidence of significant p63 expression in this lineage. Upon genotoxic stress, endogenous p63 isoforms were stabilized in both nuclear and mitochondrial subcellular compartments. Our data provide evidence of a physiological interaction between p63 with p53 whereby translocation of p63 to the mitochondria occurred through a codependent process with p53, whereas accumulation of p53 in the nucleus was prevented by p63. Using RNA interference technology, both isoforms of p63 (TA and ΔNp63) were demonstrated to confer chemoresistance, revealing a novel oncogenic role for p63 in melanoma cells. Furthermore, expression of p63 in both primary and metastatic melanoma clinical samples significantly correlated with melanoma-specific deaths in these patients. Ultimately, these observations provide a possible explanation for abrogation of the p53-mediated apoptotic pathway in melanoma, implicating novel approaches aimed at sensitizing melanoma to therapeutic agents.

Fibrous and fibrohistiocytic neoplasms: an update

Important advances in fibroblastic and fibrohistiocytic tumors relevant to dermatologists and dermatopathologists include (1) recognition that myxofibrosarcoma is a distinct entity that frequently arises in skin; (2) CD10 is sensitive but not specific atypical fibroxanthoma; (3) neurothekeomas lacking S100 expression are probably fibrohistiocytic/fibroblastic tumors, whereas S100+ myxoid variants are better classified as nerve sheath myxomas; (4) the recognition of a primary cutaneous variant of solitary fibrous tumor; (5) thelimitations of b-catenin immunohistochemistry in desmoid tumors; and (6) the prognostic utility of clinical and histopathologic variables in dermatofibrosarcoma protuberans, and the effects of imatinib mesylate therapy.

Fibrohistiocytic tumors and related neoplasms in children and adolescents

Fibrohistiocytic tumors (FHTs) in children and adolescents range from the benign fibrous histiocytoma, or dermatofibroma, to a variety of intermediate and malignant neoplasms, such as dermatofibrosarcoma protruberans and high-grade undifferentiated pleomorphic sarcoma (malignant fibrous histiocytoma). Those tumors as a group are comprised of fibroblasts, myofibroblasts, and histiocytes-dendritic cells with a variably prominent inflammatory infiltrate consisting of lymphocytes and eosinophils. Dendritic cells are also a major constituent of another group of neoplasms that include Langerhans cell histiocytosis, follicular and interdigitating cell sarcomas, and juvenile xanthogranuloma. These latter tumors are considered in this discussion for the sake of differential diagnosis and their possible histogenetic relationship to FHTs. Recent studies have suggested that the relationship between the fibroblast and histiocyte in the FHTs may reflect the intrinsic capacity to transdifferentiate from one to the other morphologic and functional state. The so-called "facultative fibroblast," as a cell with fibroblastic and histiocytic properties, was discussed in the context of the fibrous xanthoma 50 years ago. Possibly the entire histogenetic concept of FHTs should be reconsidered in light of current studies.

Study of D2-40 immunoexpression of the spindle cell areas of a metaplastic basal cell carcinoma (sarcomatoid basal cell carcinoma)

Sarcomatoid basal cell carcinoma (BCC) is rare. In the literature, data on the prognosis of such a variant is somewhat contradictory. D2-40 immunoexpression has been shown to have prognostic connotations in carcinomas of organs other than the skin. However, although D2-40 immunoexpression has been investigated in "common" (nonsarcomatoid) BCC, it has not yet been studied in the spindle cell component of a sarcomatoid BCC. We present a sarcomatoid BCC on the neck of an 87-year-old man that has grown rapidly over the last few months. The sarcomatoid component of the tumor expressed several types of cytokeratins, such as AE1/AE3, CK 5/6, 34betaE12, and CAM 5.2. It was also positive for p63 and for D2-40 in a diffuse pattern.

Clinicopathologic analysis of primary atypical fibrous xanthoma of the esophagus

AIM: To explore the clinical and pathological features of primary atypical fibrous xanthoma of the esophagus, and to analyze its diagnosis, treatment and prognosis.

METHODS: One case of primary atypical fibrous xanthoma of the esophagus treated at Fuzhou General Hospital of Nanjing Military Command of Chinese PLA was analyzed in this study. The diagnosis, treatment and follow-up data as well as histopathological and immunohistochemistry data for the disease were analyzed to reveal the clinicopathologic characteristics of the disease.

RESULTS: The tumor was located under the squamous epithelium of the upper esophagus, with a clear boundary. Histopathological analysis showed that the tumor was composed of cells of spindle, polygonal and irregular shape, collagen fibers, and esophageal glands. The tumor cells consisted of mononuclear, binuclear and polynuclear giant cells that shared some similar morphological characteristics. Mononuclear, binuclear and polynuclear giant cells could be detected in the transitional area. Some areas revealed pathological mitosis (< 2/50 HPF). Immunohistochemistry analysis showed that the tumor cells were strongly positive for CD68, CD163, S-100, and vimentin, weakly positive for α-SMA, h-caldesmon, and Ki-67 (proliferation index: ~8%), but negative of CKpan, EMA, CK (L), CK (H), F8, CD34, CD117, Dog-1, actin, desmin, CD10, and CD99.

CONCLUSION: Primary atypical fibrous xanthoma of the esophagus is an extremely rare mesenchymal tumor with benign behavior and good prognosis. A differential diagnosis should be made among atypical fibrous xanthoma of the esophagus, esophageal sarcomatoid carcinoma, carcinoma-sarcoma, leiomyoma, gastrointestinal stromal tumor, and malignant fibrous histiocytoma.