A Case of Trichoadenoma:Occurrence of a Rare Site and Immunohistochemical Staining Pattern of CD34

Trichoadenoma is a rare tumor with differentiation towards the infundibular portion of the pilosebaceous canal. Clinically, it is a nodular growth, usually on the face and buttock. Histologically, it is characterized by numerous horn cysts lined with squamous epithelium in the dermis. In this report, we describe a 44-year-old man who developed trichoadenoma on his right shin. Anti-CD34 antibody stained spindle-shaped cells in the stroma just adjacent to the peripheral layers of keratinous cysts and solid masses of squamous epithelial cells. To our knowledge, this is the first description of an occurrence of trichoadenoma in the lower leg and the first to use immunohistochemical staining to know the CD34 staining pattern.

Metastatic Adenocarcinoma Histologically Mimicking Fibrohistiocytic Tumors

Cutaneous metastasis from visceral malignancies shows diverse manifestations. Very rarely, cutaneous metastasis mimicks benign mesenchymal tumors. We describe a case in which metastasis from gastric adenocarcinoma mimicked fibrohistiocytic tumors. The diagnosis of cutaneous metastasis was confirmed by the presence of atypical cells and signet-ring cells, positive staining for mucin and positive immunohistochemical stainings for keratins, carcinoembryonic antigen(CEA), and lysozyme within the tumor cells infiltrated in the irregular, intertwining bundles of collagen in the reticular dermis.

CD34 Expression in Pyogenic Granuloma / 대한피부과학회지

BACKGROUND: The CD34(human progenitor cell antigen) is a monomeric, 115 kD glycoprotein which is expressed on hemitopoietic progenitor cells. It is also now known as an immunohistochemical marker of endothelial cell like UEA-I and factor VIII R Ag and its function is thought to be related to endot.helial adhesion, migration, and angiogenesis. OBJECTIVE: This study was aimed to investigate the patterns of CD34 expression during the early and late stages of vascular formation in pyogenic granuloma. METHOD: We performed immuinoperoxidase staining(ABC technique) by using a monoclonal anti-CD34 antibody(QBEND10, IgG1) on the formalin fixed, paraffin embedded sections of 19 cases of pyogenic granulomas. Result : 1. In all cases of pyogenic grinulomas, CD34 was strongly expressed in the endothelial cells of normal vessels in the perilobular stroma and in the endothelial cells of the mature vessels within the lobules of hemangioma. 2. In the foci of immature vessels, most of the endothelial cells located near the small vascular lumina and endothelial cells with intracellular lumen formations expressed CD34, while the endothelial cells far from the vascular lumina and endothelial cells without intracellular lumen formations mostly did not express CD:4. CONCLUSION: The above result. suggested that the expression of CD34 of the endothelial cells vary with the stage of maturation of the vessels.