Mast cells and T-lymphocytes in juvenile angiofibromas

Juvenile angiofibroma (JA) is regarded as a benign fibrovascular tumour of unknown aetiology. Due to its fibrovascular architecture the fibrous and vascular tumour component have been in the focus of most studies. This investigation aimed at characterizing inflammatory cells in JAs by immunohistochemical stainings and western blot analysis. Number and type of mast cells as well as T-lymphocytes were evaluated in a series of 10 JAs and 5 nasal mucosa (NM) specimens used as control tissue. A remarkable number of mast cells were found in JAs (14.6% of all cells). By using a combination of the mast cell markers tryptase and chymase three distinct mast cell populations could be identified: 12% expressed tryptase (T+) only, 3% stained for chymase (C+) only, and 85% were positive for both tryptase and chymase (TC+). Western blot analysis supported finding of remarkable expression of the mast cell markers tryptase and chymase in JAs and indicated for both proteins similar but also different molecular weights than being observed in NM. Furthermore an infiltration of the tumour by CD4- and CD8-positive T-lymphocytes (15.4% of all cells) was evident in immunofluorescent stainings. Compared to NM, a significantly higher number of TC+ (6.9% in JAs versus 2.7% in NM) and CD8-positive (9.7% in JAs versus 5.8% in NM) cells were found in the tumour tissue. Thus, mast cells and T-lymphocytes were identified as predominant cell types in JAs representing 30% of the cells in the tumour specimens analysed. Regarding these observations JAs are certainly not only built up by vascular cells and fibrous stroma cells. High rates of inflammatory cells like mast cells and T-lymphocytes have to be considered in this tumour.

Immunohistochemical analysis of growth mechanisms in juvenile nasopharyngeal angiofibroma

Angiogenic factors are discussed to participate in growth and promotion of juvenile nasopharyngeal angiofibroma (JNA). However, only few data are available and mechanisms remain unclear. In the presented study we analysed the expression and subcellular distribution of several angiogenic growth factors and receptors potentially involved in JNA-growth and -vascularisation. In a retrospective, descriptive, multicenter-study, we analysed 13 formalin-fixed, paraffin-embedded or cryopreserved JNA-tumors (eleven primary tumors and two recurrent ones) after immunohistochemical staining. We used monoclonal antibodies specific for transforming growth factor beta 1 (TGF-beta(1)), basic fibroblast growth factor (bFGF), the VEGF-receptors 1 and -2 (FLT-1 and FLK-1), and the hypoxia inducible factor (Hif-1alpha). Data were compared to the vessel density. Quantitative analysis of staining intensities was performed by a computer assisted quantification technique. Endothelial and stromal compartments of the samples were analysed separately. Data were compared to vessel densities and patients data. The VEGF-Receptor-2 (FLK) was frequently unregulated in the stroma and endothelium of those samples with high vessel densities. Similarly, we observed high bFGF- and TGF-beta(1) levels in the stroma of strong vascularised samples. No correlations of expression levels to patients' data were found. The reported data support the concept of JNA-growth and -vascularisation driven by factors released from stromal fibroblasts. Therefore, inhibition of these factors might be beneficial for the therapy of inoperable JNA.

Cellular Angiofibroma

Cellular angiofibroma is a recently described histologically distinctive benign mesenchymal neoplasm composed of 2 principal components, the cellular spindle cell component and prominent stromal blood vessels. Cases in males have sometimes been called "angiomyofibroblastoma-like tumor." We describe a series of 51 cases of cellular angiofibroma to further characterize its clinicopathologic and immunohistochemical features. There were 26 women and 25 men, ranging in age from 22 to 78 years (mean 53.5, median 52 years). Men tended to be older than women. Tumor size ranged from 0.6 to 25.0 cm (overall median size 3.9 cm, median in women 2.7 cm, median in men 6.7 cm). Most common sites were the vulvovaginal region (22 cases) and the inguinoscrotal region (19 cases). Preoperative duration (known for 25 patients) ranged from 1 week to 5 years, with presentation as a painless mass, except for 1 case each with intermittent genital bleeding and a painful mass. Most lesions were located primarily in subcutaneous tissue. Most cases were grossly well marginated. Two cases showed foci of hemorrhage and 1 case showed foci of necrosis. Microscopically, 41 tumors were well circumscribed, and 2 tumors infiltrated into the surrounding tissue. All tumors consisted of bland, spindle-shaped cells, short bundles of wispy collagen and numerous small- to medium-sized thick-walled vessels. Intralesional fat was present in 12 cases (6 female and 6 male cases). Mild cytologic atypia (5 cases) and frequent mitoses (3 cases) were infrequent; significant nuclear atypia and abnormal mitoses were absent. By immunohistochemistry, 29 of 48 tumors (60%) expressed CD34, 10 of 48 (21%) SMA, 4 of 48 (8%) desmin, but none expressed S-100 protein. Follow-up information was available for 40 patients (range 4-168 months; mean 31.2 months) and no patient has developed recurrence or metastasis to date.

Solitary sclerotic fibroma of skin: a possible link with pleomorphic fibroma with immunophenotypic expression for O13 (CD99) and CD34

BACKGROUND

Solitary sclerotic fibroma (SF) presents as a well circumscribed dermal nodule, composed of sparse spindle cells with alternating wavy collagen fibers arranged in a storiform pattern. The histogenesis and nature of this histologically distinct lesion are uncertain. Whether this peculiar tumor represents a true hamartoma or a degenerating end of various fibrous lesions such as pleomorphic fibroma (PF), dermatofibroma, or angiofibroma is still controversial. High proliferating index of spindle cells in SF argues against the possibility of being a degenerating end product of another lesion.

METHODS

We studied morphological features and immunoprofile of eight SFs, in comparison with four PFs, one collagenized dermatofibroma, two angiofibromas, and two periungual fibromas. Immunostains for CD34, CD31, O13 (CD99), Factor XIIIa, S-100, CD68 (KP-1), and MIB-1 were carried out using a labeled streptavidin-biotin method with DAKO-automated immunostainer. Paraffin blocks of two SFs were reprocessed for electron microscopic studies. Clinical data of all patients with SF were also reviewed.

RESULTS

Spindle cells and pleomorphic cells in SF and PF showed diffuse immunoreactivity for CD34 and O13 but were negative for CD31, S-100, and CD68. Spindle cells in one dermatofibroma and one angiofibroma were positive for Factor XIIIa. Proliferating index (MIB-1) was very low in all cases of SF, contradicting some previous reports.

CONCLUSIONS

SF is a fibrotic lesion with cells positive for CD34 and O13. It shares a common immunoprofile with PF but is distinct from dermatofibroma and other common spindle cell lesions of skin. O13 expression in SF has not been previously described.

[Immunological status of patients with juvenile angiofibroma of the skull base]

Immunological status was studied in 20 patients with juvenile angiofibroma of the base of the skull (JABS). An imbalance in the immune system was found, especially in cellular immunity (low number of T-helper and high level of T-suppressor lymphocytes, subnormal index of their proportion). The number of activated T-cells decreased, while that of NK-cells increased. JABS patients have an elevated level of serum IgA.

Extraorbital giant cell angiofibroma

A number of intriguing fibrovascular mesenchymal proliferations with benign or low grade malignant potential have recently been described. Giant cell angiofibroma was introduced as an entity by Dei Tos et al. in 1995 and initially considered to be a lesion of the orbit. We describe an extraorbital example, indicating that giant cell angiofibroma is not confined to the orbit. Immunologically, giant cell angiofibroma is positive for CD 34, bcl-2 and vimentin, and negative for epithelial and muscle markers, and S-100. The tumor shares several morphological and immunological properties with giant cell fibroblastoma and solitary fibrous tumor, yet it features a histology sufficiently characteristic to allow its categorization as a separate entity. The recommended treatment is complete but conservative excision. Metastases have not been reported.