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Pierre Chavaz

Publications and source records attributed to Pierre Chavaz.

7 recordsLinked to original sources
PubMed2003

CD44 and hyaluronate in the differential diagnosis of dermatofibroma and dermatofibrosarcoma protuberans.

The histological distinction between dermatofibroma (DF) and dermatofibrosarcoma protuberans (DFSP) may be extremely difficult. CD34 and Factor XIIIa have been used to differentiate DF from DFSP. However, there is an overlap and relative lack of specificity of their expressions. CD44 is a widely distributed integral membrane glycoprotein, which is expressed as a multitude of isoforms generated by alternative splicing of at least 10 different variant exons and post-translational modifications. CD44 is currently thought to be the principal cell surface receptor for hyaluronate (HA), the major component of the extracellular matrix. In this study we aimed to assess the expression of standard CD44 (CD44s) and its isoforms (CD44v3, CD44v4, CD44v5, CD44v6, CD44v7, CD44v7v8, and CD44v10), and HA in DF and DFSP. Immunohistochemical staining was performed on the biopsy specimens of 15 cases of DF and four cases of DFSP, using antibodies that recognize the CD44s, different CD44 isoforms and the hyaluronate binding protein (HABP). Tumor cells displayed a strong CD44s immunoreactivity in all cases of DF whereas a faint HA positivity was observed in the tumor stroma. The DF cells were negative for CD44v3, CD44v4, CD44v6, CD44v7 and CD44v7v8 but showed a strong reactivity for CD44v5 and CD44v10. In contrast, CD44s' expression was significantly reduced or absent in all DFSP lesions and the tumor stroma displayed strong staining for HA. Our results indicate that CD44 and HA can be used as additional diagnostic markers to distinguish DF from DFSP.

Dermatofibrosarcoma↗
PubMed2003

African tick bite fever: not a spotless rickettsiosis!

African tick bite fever is caused by Rickettsia africae, a newly recognized species from South Africa. We report the case of a patient with an unusual site of a tick bite and discuss cutaneous differences from other spotted fevers that may help dermatologists with clinical diagnosis.

Aged↗
PubMed2003

Decreased CD44 expression and stromal hyaluronate accumulation in myxoid dermatofibroma.

BACKGROUND: Dermatofibroma (DF) is a common benign histiocytic tumor, which has several clinicopathological variants. Myxoid DF is one of these variants, which is characterized by a stromal mucin deposition. CD44 is a polymorphic transmembrane glycoprotein and the principal cell surface receptor of hyaluronate (HA), the major component of the extracellular matrix. In a recent study, we have observed an abnormal accumulation of HA in the superficial dermis of transgenic mice with a keratinocyte-specific CD44 expression defect. We have also shown that HA was accumulated in large amounts in the superficial dermis of lichen sclerosus et atrophicus (LSA) lesions and that the epidermal CD44 expression of LSA skin was significantly decreased or lost. In an another study, we have suggested that a decrease in CD44 expression in follicular epithelial proliferations might be correlated with an abnormal HA accumulation in perifollicular solitary cutaneous myxoma. Recently we have also demonstrated that classical DF lesions displayed a strong CD44 expression in tumor cells and a weak HA positivity in tumor stroma whereas CD44 expression was significantly reduced or absent in dermatofibrosarcoma lesions and the tumor stroma showed strong HA staining. OBJECTIVE AND METHODS: Here we present 3 cases of myxoid DF, in which we explored the nature of the mucinous material in myxoid stroma by colloidal iron and hyaluronic acid binding protein stainings, as well as the expression of CD44 in the tumor cells by immunohistochemistry. RESULTS: We show that HA is accumulated in the stroma of all myxoid DF lesions with a significant decrease in CD44 expression in the tumor cells. CONCLUSION: Our results suggest that a decrease in CD44 expression in the tumor cells may result in stromal myxoid changes characterized by an abnormal HA accumulation in myxoid DF.

Adult↗
PubMed2002

Aching alopecia.

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Aged↗
PubMed2002

Basal cell carcinoma of the earlobe after auricular acupuncture.

The genesis of familial and sporadic basal cell carcinomas involves activation of the Sonic hedgehog signal transduction pathway. Other known factors for the development of basal cell carcinoma are ultraviolet exposure, X-rays, race, age, gender and decreased DNA repair capacity. We here report the case of a right earlobe sporadic basal cell carcinoma in a 65-year-old woman. This case is unusual because of its earlobe localization and its association with multiple auricular acupuncture treatments. This observation suggests a connection between local traumas, which occur in the course of acupuncture treatment and ear piercing, and the genesis of basal cell carcinoma. The incidence of minor adverse events associated with acupuncture is high, but serious events are uncommon. Acupuncture is not known to date for promoting the development of tumors. This connection remains to be elucidated.

Acupuncture, Ear↗
PubMed2002

Hyaluronate accumulation and decreased CD44 expression in perifollicular solitary cutaneous myxoma.

BACKGROUND: Myxomas are rare cutaneous tumors which may be solitary or associated with Carney's complex, NAME or LAMB syndromes. The mucinous material which constitutes the stroma of cutaneous myxomas is predominantly composed of hyaluronate (HA), the major component of the extracellular matrix. CD44 is a polymorphic integral membrane glycoprotein which serves as the principal cell surface receptor for HA. OBJECTIVE AND METHODS: Here we present 2 cases of solitary cutaneous myxomas displaying microscopically a perifollicular localization, in which we explored the nature of the accumulated mucinous material by colloidal iron and HA-binding protein stainings, as well as the epidermal expression of CD44 protein by immunohistochemistry. RESULTS: We show that HA is accumulated in the stroma of the cutaneous myxoma lesions and that the protein expression of CD44 in the keratinocytes of the trichofolliculoma-like epithelial buds projecting from the hair follicle centering these lesions is significantly decreased. CONCLUSIONS: Our results suggest that a decrease in CD44 expression in follicular epithelial proliferations may be correlated with an abnormal HA accumulation in cutaneous myxoma.

Adult↗