Biomedical subjects

V G Prieto

Publications and source records attributed to V G Prieto.

61 records · Page 4Linked to original sources

PubMed1994

Mast cells in angiolipomas and hemangiomas of human skin: are they important for angiogenesis?

To characterize the potential role of mast cells (MC) in angiogenesis, this study tests the hypothesis that MC may be more abundant in angiolipomas than in classic lipomas. MC counts were compared in 13 subcutaneous angiolipomas and 15 subcutaneous classic lipomas stained with Giemsa. Angiolipomas had ten times as many MC as did classic lipomas (25.34 +/- 2.83 versus 2.41 +/- 0.37 per mm2, mean +/- SE). To clarify whether this difference was primary (angiogenic activity) or secondary to the increased vascularity, MC were counted in 8 longstanding cutaneous capillary hemangiomas versus 13 cutaneous capillary hemangiomas of recent onset (pyogenic granulomas). If MC were mediating primary angiogenesis, one would expect them to be present in greater numbers in early than in late hemangiomas. To the contrary, however, long-standing hemangiomas were found to have significantly more MC than had those of recent onset (52.48 +/- 14.99 versus 6.59 +/- 3.37 per mm2, mean +/- SE). These results suggest that MC may not play an essential, early role in the proliferation of blood vessels in angiolipomas and hemangiomas, but rather may be related to maturation of blood vessels in these tumors.

Angiolipoma↗

PubMed1994

CD34 immunoreactivity distinguishes between scar tissue and residual tumor in re-excisional specimens of dermatofibrosarcoma protuberans.

Dermatofibrosarcoma protuberans (DFSP) is a locally aggressive tumor that often recurs after simple excision, and therefore usually requires wide surgical re-excision. It is sometimes difficult to distinguish histologically between residual tumor and scar tissue formed in response to the original biopsy. In an effort to solve this diagnostic problem, we have examined CD34 immunoreactivity in 10 primary biopsies of DFSP, 12 scars, and 7 re-excisional DFSP specimens containing residual tumor adjacent to scar tissue. In all 10 primary biopsies of DFSP, the tumor cells strongly and uniformly expressed CD34. In the 12 scars, only periadnexal cells, endothelial cells, and rare, scattered dendritic cells in the dermis were immunolabeled for CD34. In the 7 re-excisions of DFSP, the foci of residual DFSP were strongly immunolabeled, while the surrounding scar tissue was not. The pattern of CD34 immunoreactivity distinguishes DFSP from scar tissue, and thereby may permit more accurate assessment of surgical margins in re-excisional specimens of DFSP.

Antigens, CD↗

PubMed1994

CD34 staining pattern distinguishes basal cell carcinoma from trichoepithelioma.

BACKGROUND AND DESIGN: Trichoepithelioma is a benign skin tumor with follicular differentiation, which sometimes is difficult to distinguish clinically and histologically from basal cell carcinoma. One of the most helpful differences is the histologic appearance of the stroma. CD34 is an antigen known to stain the spindle-shaped cells located around the middle portion of normal hair follicles. We have stained formalin-fixed, paraffin-embedded sections of 16 trichoepitheliomas and 19 basal cell carcinomas for CD34 (anti-HPCA-1, Becton Dickinson, San Jose, Calif) to detect differences in the staining pattern and to facilitate discrimination of these two types of tumors. RESULTS: The spindle-shaped cells surrounding the islands of trichoepithelioma cells were focally strongly positive for CD34. In all basal cell carcinomas, the spindle-shaped cells surrounding the nests of tumor cells were negative; in these areas only the blood vessels were positive with this antibody. CONCLUSIONS: CD34 staining pattern differentiates between trichoepithelioma and basal cell carcinoma. CD34 stain may be helpful in distinguishing between these two tumors on small punch biopsies or in difficult diagnostic cases.

Antigens, CD↗

PubMed1994

Expression of transforming growth factor-beta 2 in malignant melanoma correlates with the depth of tumor invasion. Implications for tumor progression.

Transforming growth factor-beta 2 (TGF-beta 2) is a potent regulatory of proliferation and differentiation of both normal and malignant cells. In addition, TGF-beta 2 can exert a variety of immunosuppressive effects, suggesting that the production of this molecule contributes to impaired immunological surveillance of tumor development. In vitro, TGF-beta 2 expression has been demonstrated in cell lines derived from metastatic malignant melanocytes. but not in those derived from normal melanocytes. We sought to evaluate a potential role of TGF-beta 2 in the initiation or progression of malignant melanoma in vivo. We examined by nucleic acid in situ hybridization the expression of TGF-beta 2 mRNA transcripts in 124 melanocytic lesions including metastatic and primary invasive melanomas, melanomas in situ, nevi with architectural disorder and cytologic atypia, ordinary benign melanocytic nevi, and Spitz nevi. All metastatic melanomas and a majority (94%) of primary melanomas invasive to Clark's level III, IV, or V expressed TGF-beta 2 mRNA. A minority (41%) of Clark's level II primary invasive melanomas expressed this factor. All definitive melanomas in situ and nevi were negative. The results suggest that TGF-beta 2 expression in malignant melanoma may be a critical event in the development of deep invasion and metastases in malignant melanoma.

Base Sequence↗

PubMed1993

Lichen planus-like keratosis. A clinical and histological reexamination.

Lichen planus-like keratosis (LPLK) is a common skin lesion that has some morphologic features of lichen planus (LP) and lichenoid actinic keratosis (LAK). Although most authors consider LPLK to be a distinct lesion, surgical pathologists are often unfamiliar with it. We examined in detail the clinical and histologic features of LPLK in 100 consecutive cases. In our series, LPLK lesions occurred mostly in late-middle-aged individuals, on the trunk (64%) and extremities (31%) and predominantly in women (73%). Among the 14 histologic parameters that were studied, most LPLK had hyperkeratosis (81%) with hypergranulosis (77%), focal acanthosis (75%), and focal parakeratosis (59%). Solar elastosis was observed in 48% of the cases. Only a few cases had eosinophils (15%) or plasma cells (7%) in the inflammatory infiltrate. The adjacent skin was available for study in 71% of the specimens, and only 26.8% of the cases had an adjacent lesion, most frequently seborrheic keratosis (8.4%), solar lentigo (7%), and actinic keratosis (5.6%). According to our results, the most consistent features observed in LPLK are a lichenoid lymphocytic infiltrate with hyperkeratosis, hypergranulosis, focal acanthosis, and focal parakeratosis, without prominent atypia of keratinocytes.

Atrophy↗

PubMed1993

Immunohistochemistry detects differences between lichen planus-like keratosis, lichen planus, and lichenoid actinic keratosis.

Lichen planus-like keratosis (LPLK) (benign lichenoid keratosis) is a common skin lesion that shows some morphologic features of lichen planus (LP) and lichenoid actinic keratosis (LAK). To try to detect differences among these three entities, immunohistochemical staining for S100 protein and HLA-DR (with the antibody LN3) was performed in 31 cases of LPLK, 26 of LAK, and 25 of LP. Langerhans cells (LC) were counted per linear mm of epidermis in the S100 and LN3 slides. With anti-S100 staining, LP cases showed higher numbers of LC (mean = 25.3, SE = 2.84, median = 21.2) than did LPLK (mean = 17.3, SE = 2.26, median = 14.5) and LAK (mean = 9.7, SE = 1.5, median = 5.4). With LN3 stains, LP cases also showed higher numbers of LC than did LPLK and LAK. These results suggest that the involvement of LC in the production of lesions may be different in these three entities. However, due to the overlap in distribution of values observed, the use of these stains does not allow a definite diagnosis to be made exclusively based on the number of LC.

Adult↗

PubMedDate not supplied

Persistent atypical lymphocytic hyperplasia following tick bite in a child: report of a case and review of the literature.

We report a 6-year-old girl who developed a red papule on the posterior neck at the site of a previous tick bite. Initial biopsy was performed a year after the bite and the specimen showed a dense lymphoid infiltrate with admixed CD30+ cells. The patient was referred to our center because of concern about the development of a CD30+ lymphoproliferative disorder. The lesion was completely excised. Histology showed no evidence of a clonal lymphoproliferative disorder or Borrelia infection, but persistence of CD30+ cells. This case demonstrates that a tick bite reaction can persist for more than 1 year and show immunophenotypic and morphologic overlap with a CD30+ lymphoproliferative disorder. Complete history with thorough clinical and histopathologic evaluation is necessary to arrive at the correct diagnosis.

Animals↗