Studies for estimating the biologic behavior and prognosis of paragangliomas in the head and neck

Prognostic Factors Including Proliferation Markers Ki-67, bax, and bcl-2 in Temporal Bone Paraganglioma

Valuable criteria with which to predict the clinical behavior of the temporal bone paraganglioma or the response to treatment are lacking. The analysis of markers of cell proliferation is a possibility to estimate the prognosis. Extensive patient data on 40 temporal bone paragangliomas were gathered over the years and correlated with the data obtained by staining histologic sections with bcl-2, bax, and MIB I markers of cellular proliferation. The immunohistochemistry was in all cases negative for bcl-2, positive for bax, and for Ki-67 positive in 20% of tumors. The scores for Ki-67 did not correlate with the majority of clinical parameters, except for treatment modality, preoperative hearing loss, and cranial nerve involvement. The tendency toward poorer hearing and a higher incidence of preoperative lower cranial nerve palsies was demonstrated in patients with higher Ki-67 scores. Furthermore, the higher rate of subtotal tumor removals in these patients reveals technical difficulties in accomplishing a radical removal, although the incidence of residual tumors was thus not affected. In view of the present information obtained with proliferation markers, the site of tumor origin still remains the most predictive variable for the course of the disease.

Immunohistochemical analysis and biological behaviour of gastric glomus tumours: a case report and review of the literature

Gastric glomus tumours are rare and clinically recognized as benign. Nevertheless, some show biological behaviour similar to that of malignant lesions. During the last 40 years, we have encountered only one gastric glomus tumour. Analysis of frozen sections of this tumour suggested a mesenchymal tumour with malignant potential. Three mitoses per 50 high-power fields, with no cytological abnormalities, were observed. Tumour cells were positive for α-smooth muscle actin, vimentin and actin but negative for CD117, S-100 protein, creatine kinase, desmin, CD68, collagen type IV, CD34 and p53. The post-operative period was uneventful. During 37 months' follow-up, no recurrence or metastasis was detected and a benign course was considered likely. Literature on the immunohistochemistry and biological behaviour of gastric glomus tumours was also reviewed. Immunohistochemical studies are helpful in the differential diagnosis of gastric glomus tumours: although most are benign, malignancy cannot be excluded. Thus, long-term follow-up of the patient is necessary.

G2M arrest, blocked apoptosis, and low growth fraction may explain indolent behavior of head and neck paragangliomas

Head and neck paragangliomas are characterized by unusually slow growth and a strong hereditary component, which is associated with inactivating mutations in subunits of complex II of the mitochondrial respiratory chain. It is unclear how mutations induce tumorigenesis and lead to the indolent clinical behavior that often plays a prominent role in treatment strategies. To better understand the natural course of the tumors, we studied a number of growth-related parameters in 42 hereditary and sporadic paragangliomas. Computerized image analysis showed that the fraction of Ki-67-positive cells was generally below 1%, in accordance with the slow growth. Weak or negative immunohistochemical staining indicated wild-type TP53 status, whereas p-21(waf) expression was heterogeneous. Most tumors showed strong expression of Bcl-x(L), and no apoptotic cells could be detected with the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling assay. Flow cytometry showed abnormal DNA content profiles in 52% of the tumors, including overt aneuploidy as well as G(2)/M arrest or tetraploidization. These results fit into a model in which a stress-activated cell cycle checkpoint at the G(2) to M transition and inhibition of apoptosis permit the expansion of only a minor fraction of cycling cells with high likelihood of polyploidization.

Biologic characteristics of paragangliomas of the nasal cavity and paranasal sinuses

Paragangliomas of the nasal cavity and paranasal sinuses are extremely rare. This study was conducted to investigate the biologic characteristics of these lesions on different molecular levels and to estimate their biologic behavior. Operative specimens of three patients who underwent surgery for a paraganglioma of the nasal cavity (one case) or paranasal sinuses (two cases) were investigated by routine histology, quantitative DNA analysis, and immunohistochemical assessment of proliferation markers (i.e., Proliferating Cell Nuclear Antigen, PCNA; Ki67-MIB-1), the expression of cell-surface antigens, which reflect the tumor-stroma interaction (i.e., CD 44 v0.4/5 and 6, CD 54, CD 106), oncogene products (nm-23; p53), and bcl-2 as a marker of apoptosis. Histologically, two tumors were paragangliomas of the adenomatous subtype, one lesion was classified as angiomatous. According to DNA analysis, aneuploid cells were detected in all tumors. Two of three paragangliomas were classified as a DNA type III pattern, implying a high percentage of aneuploid cells and an aggressive behavior. Immunohistochemically, paragangliomas of the nasal cavity showed increased scores for both proliferation markers tested, indicating a rapid growth pattern. According to the expression of cell-surface markers and oncogene products, these tumors displayed an aggressive behavior and an infiltrating growth pattern. The highest value for the parameters of quantitative DNA analysis and highest proliferation scores were found in a tumor of a patient who developed multiple tumor recurrences after radical excision of the lesion with clear margins, and finally died of disease. In conclusion, paragangliomas of the nasal cavity and paranasal sinuses examined in this study should be regarded as suspicious concerning their biologic and clinical behavior. Radical excision, and in cases with highly aggressive biology, postoperative radiation therapy are recommended. Tumor biologic examinations can help to recognize high-risk patients for developing recurrences and possibly lesions with a malignant behavior and to enhance our understanding of the biology of these extremely rare tumors of the nasal cavity and paranasal sinuses.