APC gene mutations and colorectal adenomatosis in familial adenomatous polyposis

Correlations between germline APC mutation sites and colorectal pathophenotypes, as evaluated by the direct count of adenomas at colectomy, were investigated analysing colectomy specimens from 29 FAP patients carrying one mis-sense (codon 208) and 14 frame-shift or non-sense APC mutations (codons 232, 367, 437, 623, 876, 995, 1061, 1068, 1075, 1112, 1114, 1309, 1324, 1556). The mis-sense mutation at codon 208 was associated with a relatively mild colorectal pathophenotype. The mutation at codon 367, subject to alternative splicing, was associated with attenuated FAP. The mutation at codon 1309 was associated with the profuse colorectal adenomatosis. For 13 mutations, predicted to result in null alleles or truncated APC proteins, we correlated density and distribution of colorectal adenomas with the predicted functional effects of the mutation. The most severe colorectal pathophenotype was significantly associated with the truncating mutation at codon 1309, which is located downstream to the I beta-catenin binding domain but upstream II beta-catenin-binding domain. Mutations between codons 867 and 1114, which affect the I beta-catenin binding domain, as well as mutations occurring in exons 6 and 9, predicted to result in null alleles, were associated with a less severe colorectal pathophenotype. Overall, the highest number of adenomas was detected in the right colon, followed by the left colon, transverse colon sigma and rectum. However, the highest density of adenomas was observed in the left colon, followed by the right colon, sigma, transverse colon and rectum. Colorectal carcinomas, observed in only five patients, were all in the left colon.

[An angiogenesis study of Dukes' B colonic tumors]

PURPOSE

To evaluate the angiogenesis in Dukes' B colon cancer.

PATIENTS AND METHODS

In 60 patients (age, 39-75 years), the microvessel density and the relationship between the angiogenesis and other histologic features were retrospectively evaluated. In an ongoing prospective study, 25 patients have been enrolled to determine the possible therapeutic implications of VEGF quantitative analysis.

RESULTS

The retrospective portion of this study confirms the prognostic value of the angiogenesis in terms of recurrences and survival. At present, no conclusions can be drawn from the prospective portion of the study.

Unbalanced germ-line expression of hMLH1 and hMSH2 alleles in hereditary nonpolyposis colorectal cancer

We analyzed the hMLH1 and hMSH2 genes in 30 unrelated hereditary nonpolyposis colorectal cancer (HNPCC) patients using mutational and immunohistochemical analyses combined whenever possible with primer extension assays, designed to estimate hMLH1 and hMSH2 transcript expression in peripheral blood lymphocytes. Single-strand conformational polymorphism screening and PCR-direct sequencing revealed seven hMLH1 and five hMSH2 sequence variants in 14 unrelated HNPCC patients, including three definite pathogenic mutations, four amino acid substitutions of uncertain pathogenic significance, and five polymorphisms. Immunohistochemistry indicated the lack of either hMLH1 or hMSH2 protein expression in tumors from 13 patients, and the absence of both hMLH1 and hMSH2 immunostaining was observed in the tumor from one additional case. The lack of hMLH1 or hMSH2 immunostaining was associated with the presence of microsatellite instability in the corresponding tumor and was also observed in tumors from patients negative for pathogenic mutations by mutational screening. There was a marked unbalance in the allelic expression of either hMLH1 or hMSH2 transcripts in three of eight unrelated HNPCC patients that could be analyzed, although a less marked unbalance was detected in two additional patients. Tumors from patients with germ-line unbalance in hMLH1 or hMSH2 transcript expression did not express the corresponding mismatch repair protein and displayed microsatellite instability. Our results indicate that constitutional alterations in hMLH1 and hMSH2 transcript expression may represent genetic markers for HNPCC carrier status also in cases in which mutational analysis did not detect a definite pathogenic variant. This suggests that transcript deregulation may represent a relevant mode of germ-line inactivation for mismatch repair genes.

Prognostic significance of microsatellite instability in sporadic mucinous colorectal cancers

We investigated the prognostic significance of microsatellite instability (MI) in 50 consecutive patients with sporadic mucinous colorectal cancer who had undergone only surgery. We evaluated MI and the pathological features with a possible prognostic value for each tumor, and the effect of the examined parameters on patients' outcome was statistically analyzed (univariate and multivariate analysis). All patients were followed-up for a minimum of 72 months or until death; in evaluating survival, only deaths of colorectal cancer were considered. DNA extracted from tumor sections and the corresponding normal tissue was analyzed by polymerase chain reaction at six microsatellite loci: D2S123, D3S1611, D3S49, D5S107, BAT26, BAT40. Alterations at two or more loci were detected in 36% of cases (MI+ tumors). MI+ and MI- cancers differed significantly in the pattern of growth, and most MI+ tumors showed an expanding type of growth (72.2%, P = .005). At univariate analysis, improved survival rate was significantly associated with MI, as well as with the following parameters: expanding cancer growth, Dukes stage, and absence of venous invasion. Nevertheless, at multivariate analysis, only the pattern of cancer growth and Dukes stage were independent prognostic factors, whereas the effect on survival of MI and venous invasion was found to be negligible. In our study, MI+ and MI- cancers differ only on the pattern of growth; therefore, our data suggest that the better survival rate in mucinous cancers with genomic instability is strictly related to their less aggressive type of growth.

Correlation between DNA content and p53 deletion in colorectal cancer

OBJECTIVE

To find out whether tumour DNA content correlates with allelic loss of p53 and other pathological features in primary colorectal carcinomas.

DESIGN

Ongoing prospective study.

SETTING

University hospital, Italy.

SUBJECTS

128 patients who had undergone radical resections for colorectal carcinoma.

INTERVENTIONS

Flow cytometric measurement of tumour DNA content and detection of allelic loss on the short arm of chromosome 17 by Southern blot (restriction fragment length polymorphism) analysis in fresh tumour specimens.

MAIN OUTCOME MEASURES

Correlation between DNA ploidy and deletion of p53, as well as between these two genetic events and clinicopathological variables.

RESULTS

Interpretable DNA histograms were obtained for 122 tumour specimens. Forty-three tumours (35%) were diploid and 79 (65%) aneuploid. The diploid tumours were significantly more common in the proximal colon (from the caecum to the splenic flexure) than in the distal colon (from the descending colon to the rectum) (p = 0.002). The allelic state on the short arm of chromosome 17 was evaluated in 80 heterozygous patients. Forty-four tumour specimens (55%) showed deletion of 17p. Allelic loss of p53 was significantly more common in the distal and rectal tumours than in the proximal ones (p < 0.0001). Aneuploidy was more common among those tumours which had shown deletion of p53 than in those that had not (p = 0.0008).

CONCLUSIONS

DNA aneuploidy was significantly associated with the deletion of the p53 gene. This suggests that the functional loss of p53 may favour the growth and establishment of an aneuploid cell population within tumours. Tumours of the proximal and distal colon differ in their genetic nature.

Anatomic plane of separation between external anal sphincter and puborectalis muscle: clinical implications

PURPOSE

The possible existence of an anatomic and functional separation between the external sphincter and the puborectalis muscle has been reported in the medical literature. In this article we confirm, by means of anatomic and clinical observations, the presence of such a separation, focusing on its importance in understanding the pathway of diffusion for some suppurative anal lesions and to plan advanced sphincter-sparing procedures.

METHODS

Twenty adult anatomic specimens of the anal region (12 from women) were cut in the sagittal, coronal, and paracoronal planes, stained with hematoxylin and eosin, and examined. The pelvic floor musculature was examined in three patients undergoing postanal repair operations. Thirty primary posterior and posterolateral anal fistulas, preoperatively classified as transsphincteric (22) or suprasphincteric (8) were carefully traced during and after staged fistulotomy in 30 (11 female) patients, and their relationship with puborectalis muscle and external sphincter was evaluated. An attempt was made peranally to separate the external sphincter from the puborectalis muscle in four patients (3 females) aged 56 to 65 years with rectal cancers 4 to 5 cm from the anal verge so as to perform a sphincter-sparing procedure.

RESULTS

A connective plane of separation between puborectalis muscle and external sphincter was clearly identified in 14 (70 percent) anatomic specimens. In three (21 percent) cases the two muscles presented a pronounced overlapping arrangement. An anatomicofunctional separation between puborectalis muscle and external sphincter was easily demonstrated during post-anal repair operations. All fistulous tracks ran between the external sphincter and puborectalis muscle, despite the pronounced upward direction of the ones preoperatively classified as suprasphincteric. A plane of separation between puborectalis muscle and external sphincter was identified and developed in four patients with very low rectal cancers. An abdominoperanal rectolevatorial excision was performed. A coloanal anastomosis was performed on the residual lower anal canal.

CONCLUSION

An anatomic plane of separation is present between the puborectalis muscle and the external sphincter. The presence of this plane is important to help understand the diffusion of some suppurative anal lesions and to plan advanced sphincter-sparing procedures.

Transcripts with splicings of exons 15 and 16 of the hMLH1 gene in normal lymphocytes: implications in RNA-based mutation screening of hereditary non-polyposis colorectal cancer

Germline mutations of the hMLH1 gene are estimated to account for a large fraction of kindreds affected by hereditary non-polyposis colorectal cancer (HNPCC). In a significant number of cases, hMLH1 mutations result in the expression of truncated proteins. We report here two novel alternatively spliced forms of hMLH1 mRNA in normal lymphocytes. One of these novel isoforms lacks the coding region of the gene between codons 557 and 578, corresponding to the entire exon 15. The deletion introduces a frameshift that results in a premature stop signal. The other isoform is characterised by an in-frame deletion spanning codons 578-632, corresponding to loss of the entire exon 16. Further studies are necessary to establish the biological significance of these alternative splicings. The presence of alternatively spliced hMLH1 transcripts that mimic pathogenic mutations should be taken into account in the mutational screening of the hMLH1 gene by reverse transcription-polymerase chain reaction methodologies.

Character of the invasive margin in colorectal cancer: does it improve prognostic information of Dukes staging?

PURPOSE

The clinical significance and prognostic value of the histopathologic parameters used in both the Dukes and Jass classifications were evaluated to select those with an independent effect on survival after radical surgery for colorectal cancer.

METHODS

The depth of local spread (limited to the bowel wall or extended beyond it), the number of metastatic lymph nodes (none, 1-4, more than 4), the character of the invasive margin (pushing or infiltrating), and the presence or absence of conspicuous peritumoral lymphocytic infiltration were assessed in 235 patients who had undergone radical resection for colorectal cancer. The influence of these variables on survival was studied by univariate and multivariate analysis.

RESULTS

No significant difference in survival was found between patients with conspicuous peritumoral infiltrate and those without it; moreover, multivariate analysis failed to show any independent prognostic value for either lymphocytic infiltration or depth of local invasion. However, the character of the invasive margin and the number of metastatic lymph nodes were identified as the only variables with any independent importance on survival. Based on these data, a new prognostic model may be proposed; it uses the character of the infiltrative margin as a discriminating factor among patients within the lymph node-negative (Dukes A and B stages) and lymph node-positive (Dukes C1 and C2 subsets) groups. A good prognosis for Dukes A, B, and C1 patients was associated with pushing tumors; C1 and C2 patients with infiltrating tumors had a poor prognosis. On the whole, the new prognostic model has allowed for the placement of 59.6 percent of our patients into groups that provide a confident prognosis. The clinical outcome of Dukes A and B patients with infiltrating tumors is still uncertain.

CONCLUSIONS

The character of the invasive margin is an important prognostic factor in colorectal cancer. The association of this parameter with the traditional Dukes classification may provide additional useful prognostic information and aid in the selection of those patients who could most benefit from adjuvant therapy.

Microsatellite instability in sporadic mucinous colorectal carcinomas: relationship to clinico-pathological variables

A series of 44 sporadic mucinous colorectal carcinomas was analysed for microsatellite instability; 30 consecutive sporadic non-mucinous colorectal cancers served as controls. Mucinous carcinomas showed microsatellite instability more frequently than non-mucinous cancers: 26/44 and 8/30, respectively (P = 0.005); the difference was higher for cancers with two or more microsatellite alterations: 12 of the 44 mucinous carcinomas versus one of the 30 non-mucinous carcinomas (P = 0.007). On comparing the clinico-pathological features of mucinous carcinomas with and without microsatellite instabilities, no differences were found with respect to the following variables; sex ratio, tumour localization, tumour size, peritumoural lymphocytic infiltration, Crohn's-like lymphoid reaction, peritumoural fibrosis, Dukes' stage, and relationship with adenoma. Mucinous cancers with DNA replication errors were characterized by three features: onset in younger patients (P < 0.05); exophytic gross shape (P = 0.03); and an expanding pattern of growth (P = 0.003). Of the 12 mucinous carcinomas with instability in two or more microsatellites, ten (83.3 per cent) exhibited an expanding pattern of growth, while mucinous cancers with instability in one microsatellite or without genomic instability showed no distinctive growth pattern. This study confirms the relationship between microsatellite instabilities and mucin production in colorectal carcinomas, but shows that replication error RER-positive and RER-negative mucinous cancers differ in few clinico-pathological features. These differences are only in part similar to those previously reported in RER-positive colorectal carcinomas. These data indicate that mucinous carcinoma of the large bowel could represent a histological subset separate from other histotypes.

[A case of primary hepatic carcinoid. A report of its surgical resolution]

Primary hepatic carcinoid tumors are extremely rare; conversely, the liver is the most frequent site of metastases from gastrointestinal carcinoids. Clinically, primary lesions are characterized, in most cases, by the absence of an overt endocrine syndrome. Histologic findings and immunohistochemical demonstrations of chromogranin and neuron specific enolase, generally, enable the neuroendocrine origin of these neoplasms to be established. Prognosis after surgical treatment of primary hepatic carcinoids seems to be more favorable when compared with other hepatic carcinomas.

Metastatic tumor of the spermatic cord from a primary silent colorectal adenocarcinoma

Tumors of the spermatic cord are indeed rare and 91% are of mesenchymal origin. Nearly all epithelial tumors are metastases with the primary tumor located in the gastrointestinal tract, prostate, kidney. In 9.5% of cases, initial symptoms are localized to the metastatic site prior to the discovery of the primary tumor. When a diagnosis of epithelial malignant tumor of the spermatic cord is made an investigation for the primary site must be performed. We report a case of metastatic tumor of the right spermatic cord occurring as first clinical manifestation of a silent adenocarcinoma of the sigmoid colon.

Immunohistochemical vs molecular biology methods. Complementary techniques for effective screening of p53 alterations in head and neck cancer

The purpose of this study was to correlate p53 gene alterations and their expression in 85 head and neck squamous cell carcinomas. Genomic p53 was amplified with the polymerase chain reaction (PCR) from formalin-fixed, paraffin-embedded tissues. Exons 5 through 8 were screened for mutations by means of non-isotopic single-strand conformation polymorphism (SSCP) analysis. p53 expression was detected by means of immunohistochemistry (IHC) with the p53 monoclonal antibody DO-7. Twenty-three lesions (27%) showed both SSCP variants and DO-7 immunostaining, whereas 37 (44%) demonstrated both SSCP normal patterns and negative staining. Twenty-five lesions (29%) were discordant, including 12 IHC-positive (14%) and 13 SSCP-positive (15%) lesions. However, discordant IHC-negative, SSCP-positive lesions could have been easily interpreted after sequencing of the abnormal samples. Had these been screened with IHC only, all nonsense or frameshift p53 mutations would have been missed. IHC-positive, SSCP-negative lesions were interpreted in light of current models of p53 immunodetection. Had these been screened with SSCP or sequencing only, a sizeable number of tumors expressing p53 protein abnormalities would have been undetected. Therefore, simultaneous use of both methods increases the number of p53 abnormalities detected, and is warranted.

[Sacrococcygeal chordoma simulating pilonidal cyst]

Chordoma is a rare neoplasm arising in the cerebrospinal axis from nothochordal remnants. The commonest location is in the sacrococcygeal area, then in the sphenooccipital region and less frequently in other parts of the vertebral column. Chordoma has been found in all age groups, but the greatest incidence was found between the fifth and the seventh decades: there is a male predominance. Signs and symptoms of chordoma are related to tumor location and are often present for a long period of time because of the slow growth of the neoplasia. Sacrococcygeal chordomas may produce lower back pain, bladder or anorectal dysfunction or mass. Three histologic subtypes are currently considered: conventional, chondroid and dedifferentiated chordoma. Comparing with conventional chordoma, chondroid chordoma shows a better prognosis while dedifferentiated chordoma has a worse prognosis. However the malignant potential of chordoma is most likely due to incomplete surgical excision because of the multifocality of the neoplastic growth. For that reason, local recurrence is common and accounts in large part for the mortality for this tumor. The best treatment consists of a wide surgical excision coupled with adjuvant radiation therapy. We report a case of sacrococcygeal chordoma arised in a 48 year-old-man; the clinical features of the tumor showed a close resemblance with a pilonidal cyst. When the diagnosis of conventional chordoma was done the patient were treated by surgery and by intraoperative radiotherapy followed by external radiotherapy. This peculiar therapy was adopted in the attempt to reduce the risk of local recurrence. Six months after this treatment the patient was well and no signs of local recurrence was found by the magnetic resonance imaging.

Chronic viral hepatitis induced by hepatitis C but not hepatitis B virus infection correlates with increased liver angiogenesis

Chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infections lead to cirrhosis and increase the risk for the development of hepatocellular carcinoma (HCC). Angiogenesis is an essential step in oncogenesis and contributes to tumor progression in adult organs; however, to what extent angiogenesis occurs in the liver during chronic viral hepatitis has not been studied. Ninety-nine matched patients affected by chronic hepatitis due to either HBV or HCV were studied together with 13 controls (5 patients were affected by familial hyperbilirubinemia with normal liver histology; 6 patients with stage II primary biliary cirrhosis; and 2 patients with pseudo inflammatory tumor). Microvessel density was assessed in liver biopsies by immunostaining using two different antibodies against endothelial cell antigens, QB-END/10 and Factor VIII. In addition, the liver homogenates and sera of HCV- or HBV-positive patients and controls were tested for their capacity to stimulate the migration and proliferation of freshly isolated human endothelial cells in vitro. Evidence of angiogenesis was significantly more frequent in HCV-positive patients compared with HBV-infected subjects or controls (74% vs. 39% vs. 8%) (chi2 = 20.78; P < .0001) (HCV+ vs. HBV+ vs. controls). The degree of microvessel density was also higher in HCV- than in HBV-positive patients or controls (chi2 = 12.28; P < .005). In addition, HCV-positive sera and liver homogenates stimulated a higher migration and proliferation of human endothelial cells in vitro compared with HBV-positive or control sera and liver homogenates. These observations indicate that angiogenesis is particularly linked to HCV infection, suggesting a possible contribution to HCV-related liver oncogenesis.

Primary signet-ring cell carcinoma of the colon and rectum

PURPOSE

Colorectal signet-ring cell carcinoma (SRCC) is uncommon; discordant data have been previously reported about clinicopathologic features. Thirty-four cases of primary colorectal SRCC were retrospectively reviewed to clarify controversies.

METHODS

Primary colorectal SRCC was diagnosed when the following criteria were satisfied: 1) the tumor was primary; 2) histologic material was adequate; 3) signet-ring cell represented more than 50 percent of the cancer.

RESULTS

We identified 34 cases (1.1 percent) of 2,995 consecutive large bowel cancers collected at the Institute of Anatomic Pathology of Florence between 1985 and 1993. Patients ranged in age from 31 to 89 (mean, 63.5; median, 65) years; 19 were male, and 15 were female (male:female = 1.3:1). Fifteen tumors were located in the proximal colon, 11 in the rectum, and 8 in the distal colon. The gross shape was infiltrative in 24 cases and exophytic in 10; only 6 cases (17.6 percent) showed features of linitis plastica. Most cancers (61.8 percent) were Stage C, 29.4 percent were Stage B, and distant metastases were present in only three cases (8.8 percent). No Stage A case was found. Prognosis was extremely poor, and overall five-year survival rate was 9.1 percent. Survival was influenced significantly by tumor stage (P < 0.01).

CONCLUSIONS

Comparison of our data with the literature showed many differences that could be related to different applied diagnostic criteria. We underlined the importance of histology as reproducible criterion for diagnosis of primary colorectal SRCC.

[Magnetic resonance with endorectal coil in the locoregional staging of rectal carcinoma]

The accurate locoregional staging of rectal cancer is important in choosing and planning therapy. The diagnostic contribution of endorectal ultrasonography and of Computed Tomography is well known because both methods have been widely used in the last ten years. More recently, Magnetic Resonance Imaging (MRI) has been introduced in the preoperative staging of rectal cancer: most interestingly, in the last three years endorectal surface coils have become available as a clinical device. February through November, 1994, twenty patients affected with rectal carcinoma were examined with endorectal MRI. In order to assess their accuracy, MR staging results were compared with pathologic findings. MRI was performed with an 0.5 T system equipped with an endorectal surface coil. In all cases T2-weighted turbo spin-echo sequences were performed on axial and sagittal or coronal planes. Rectal wall layers were reliably demonstrated in all patients. The comparison with pathologic findings showed 78.9% MR accuracy in assessing tumor infiltration depth. In addition, the study of perirectal lymph nodes showed 83.2% MR sensitivity and 53.8% MR specificity. The high resolution images obtained using endorectal surface coils and the well-known panoramic capabilities of this method reveal MR potentials in rectal carcinoma staging.

[Expression of p53 in the skin in systemic sclerosis. Immunohistochemical study of 8 cases]

P53 gene belongs to the family of "Tumor suppressor gene". It encodes a nuclear phosphoprotein involved in cell proliferation control; mutations of p53 gene are the most common genetic alterations found in human tumors. These mutations may cause the production of an altered protein that usually loses its physiological function. The mutant p53 protein is more stable than the wild type form and it is immunohistochemically detectable. Systemic Sclerosis is characterized by activation of fibroblasts, endotheliocytes and lymphocytes; furthermore, in this disease, a proto-oncogenic activation has already been shown in fibroblasts and lymphocytes. The aim of this study was to verify p53 expression in the skin of SSc patients. Eight patients, all classified in the limited cutaneous subset of SSc, after informed consent, underwent skin biopsies of the affected and apparently unaffected skin. P53 was investigated by immunohistochemistry, using a monoclonal anti-p53 antibody (DO-7), on formalin fixed, paraffin embedded tissue. P53 immunoreactive cells were found in 4 out of 8 biopsies; in all cases the positivity was confined to cells of the basal layer of the epidermis, histologically identified as keratinocytes. A large case series and a molecular biology approach are needed to support these preliminary observations.

HPV and p53 in urinary bladder carcinoma

We report a study on human papilloma virus (HPV) and p53 protein in 18 cases of urothelial carcinoma grade 1, 2 and 3. The presence of HPV has been correlated to the p53 protein expression, as this virus, once integrated in the cell nuclei, seems to cause the alteration of some genes expression, involved in the cell-cycle regulation, like p53. One case of urothelial papillary carcinoma grade 2, infiltrating the lamina propria, resulted to be positive for HPV type 31/33/51 and for p53 protein. Our data suggest that HPV type 31/33/51 may have played a role in the pathogenesis of this neoplasia causing an alteration of p53 gene.

[Extensive lymphadenectomy in the therapy of cancer of the left colon and rectum: an analysis of the anatomicopathological data]

In the last 12 years in our surgical service, radical resection was performed in 142 patients with cancer of left colon and in 145 patients with rectal cancer. Extended lymphadenectomy was always realized: preaortocaval lymphadenectomy in colonic cancer; preartocaval and pelvic lymphadenectomy in rectal cancer. The incidence of C stage was 40.14% in cancer of left colon and 40.68% in rectal cancer. Neoplastic diffusion in preaortocaval lymph nodes was only in a patient with colonic cancer, never in patients with rectal cancer. The incidence of neoplastic diffusion in pelvic nodes was 3.12% (0 in superior rectum; 6.25% in medium rectum; 2.4% in inferior rectum). In 1 of 90 patients with tumour of medium or inferior rectum, we relieved tumoural involvement of pelvic nodes without neoplastic diffusion in regional nodes. These anatomo-pathological data subline: a) the low incidence of neoplastic diffusion in preaortocaval nodes in cancer of left colon and rectum; b) the importance of pelvic lymphadenectomy in cancer of medium and inferior rectum.

Prognostic significance of accessory cells and lymphocytes in nasopharyngeal carcinoma

Forty-five consecutive biopsy specimens of nasopharyngeal carcinoma (NPC) and 10 biopsies of healthy nasopharyngeal mucosa obtained from non-cancer patients were investigated by immunohistochemical methods. Monoclonal (B2, T1) and policlonal antibodies (against S-100 protein and lysozyme) with reference to infiltrating lymphocytes and accessory cells (monocytic/macrophagic and dendritic cells) were used. Variable population densities of dendritic cells (S100+) were demonstrated in 22 out of the 45 cases (49%) of NPC; the distribution of these cells was typically within the cancer nests. Monocytic/macrophagic cells (Lys+) were found along the tumor margins and interspersed among the tumor cells in 14 out of 45 (31%) cases. No significant statistical correlation between density of accessory cells and histological type of NPC (classified according to Micheau criteria) was found. Cases with a moderate to marked density of dendritic and monocytic/macrophagic cells survived longer than those with a slight one (mean survival of 63%, 67% and 29%, 27% respectively). In NPC tissues T-lymphocyte infiltration was prevalent. In contrast, B cells were numerous and T cells rare in normal control tissues. The intensity of T-cell infiltration was significantly high in cases with a marked density of S-100+ cells, according to the ability of these cells to present antigens to sensitized T-cells. This study suggests a prognostic significance for reactive cells infiltrating NPC, which means longer survival for cases associated with marked infiltration density of accessory cells.

[Paraganglioma (chemodectoma) of the larynx. Presentation of 2 cases]

Two rare cases of laryngeal paraganglioma are reported. The first patient was a 14-year-old girl, that had a new laterocervical paraganglioma, 4 years after the excision of a laryngeal tumor. The other patient was a 33-year-old man. In both the cases, the diagnosis was made on histopathological ground and the tumors displayed the typical histological pattern of paragangliomas: epithelioid tumor cell arranged in nests (Zell-ballen) in a vascular stroma. Neoplastic cells were found to contain argyrophil granules and chromogranin. Laryngeal paragangliomas reported in the literature are 73, they generally are supraglottic, show no sex predilection and prefer the V-VII decades of age.