Prominent Lymphocytic Infiltration Research Articles

Frameshift-mutation-derived peptides as tumor-specific antigens in inherited and spontaneous colorectal cancer.

The functional role and specificity of tumor infiltrating lymphocytes (TIL) is generally not well characterized. Prominent lymphocyte infiltration is the hallmark of the most common form of hereditary colon cancer, hereditary nonpolyposis colon cancer (HNPCC) and the corresponding spontaneous colon cancers with the microsatellite instability (MSI) phenotype. These cancers are caused by inherited or acquired defects in the DNA mismatch-repair machinery. The molecular mechanism behind the MSI phenotype provides a clue to understanding the lymphocyte reaction by allowing reliable prediction of potential T cell epitopes created by frameshift mutations in candidate genes carrying nucleotide repeat sequences, such as TGF beta RII and BAX. These tumors therefore represent an interesting human system for studying TIL and characterizing tumor-specific T cells. We here describe T cell reactivity against several T helper cell epitopes, representing a common frameshift mutation in TGF beta RII, in TIL and peripheral blood lymphocytes from patients with MSI(+) tumors. The peptide SLVRLSSCVPVALMSAMTTSSSQ was recognized by T cells from two of three patients with spontaneous MSI(+) colon cancers and from all three patients with HNPCC. Because such mutations are present in 90% of cancers within this patient group, these newly characterized epitopes provide attractive targets for cancer vaccines, including a prophylactic vaccine for individuals carrying a genetic disposition for developing HNPCC.

Non‐alcoholic sclerosing pancreatitis with Sjögren's syndrome and tubulointerstitial nephritis

We recently encountered a 56‐year‐old Japanese man with pancreatitis who had hyperglobulinemia, was autoantibody‐positive and responded to steroid therapy. The patient had been found to have asymptomatic proteinuria at an annual medical check‐up and had experienced a dry mouth for several years. He was diagnosed as having Sjögren's syndrome indicated by the dry mouth and positive findings from a lip biopsy and a Schirmer's test. Tubulointerstitial nephritis, causing proteinuria, was verified by percutaneous renal biopsy. Antinuclear antibody was positive at the 1 : 160 titer. Serum γ‐globulin and IgG values were markedly increased, whereas complement components C3 and C4 were lowered. Abdominal computed tomography and ultrasonography demonstrated a diffusely enlarged pancreas without localized pancreatic mass or para‐aortic lymphadenopathy. Neither calcification nor cysts were detected in the pancreas. Endoscopic retrograde cholangiopancreatography revealed a diffuse narrowing of the main pancreatic duct with an irregular wall. Wedged biopsy specimens of the pancreas by an exploration of the abdomen showed prominent lymphocytic infiltrates including some plasmacytes, as well as decreased exocrine parenchyma and inter‐ and intralobular fibrosis. These findings suggested a diagnosis of autoimmune‐related pancreatitis. Steroid therapy was carried out with a marked improvement of his clinical symptoms and laboratory data.

Lymphocytic infiltration in undifferentiated nasopharyngeal cancer.

Undifferentiated nasopharyngeal carcinoma (NPC) is characterized by prominent lymphocytic infiltration. Although the lymphoid infiltrate in NPC has been examined extensively in morphologic and immunocytochemical studies, the significance of this lymphoid infiltrate and its correlation with prognosis has been a subject of controversy for years. To elucidate the significance of lymphoid infiltration in undifferentiated NPC. Evaluation of the relationship between lymphocytic infiltration in NPC and cervical lymph node status, ultrastructural examination of the lymphoid infiltrate, and assessment of lymphocytic infiltration as an independent prognosticator of regional node metastasis. Lymphocytic infiltration was evaluated quantitatively in 20 cases of undifferentiated NPC using light microscopy. Four cases of undifferentiated NPC were processed for conventional electron microscopy. The effects of degree of lymphocytic infiltration, age, and tumor stage on cervical nodal metastasis were analysed using the logistic regression model. The degree of lymphoid infiltration correlated with cervical nodal metastasis (P<.001). Ultrastructural evidence of lymphocytes destroying cancer cells was seen. Lymphocytic infiltration was found to be an independent factor affecting cervical nodal metastasis (P =.02, univariate analysis; P =.03, multivariate analysis). The lymphoid infiltrate is beneficial in undifferentiated NPC, and its presence may deter regional metastasis of cancer cells to the cervical nodes.

Fine‐needle aspiration of breast carcinomas with prominent lymphocytic infiltrate

Fine‐needle aspiration of breast carcinomas with prominent lymphocytic infiltrate

Fine-needle aspiration of breast carcinomas with prominent lymphocytic infiltrate.

Carcinomas of the breast with prominent lymphoplasmacytic background are commonly encountered in cytology. The aim of this study was to assess the prevalence of different types of carcinomas that share this common feature, identify possible distinguishing cytologic features, and evaluate the diagnostic pitfalls in this group of tumors. Eighteen fine-needle aspirations (FNAs) of breast carcinomas with heavy lymphoplasmacytic background were reviewed. Histologic follow-up was reviewed in all cases. Of 18 cases, there were 9 invasive ductal carcinomas (IDC), and 9 medullary carcinomas (6 typical and 3 atypical). FNAs from typical medullary carcinomas (TMC) showed more severe nuclear atypia and macronucleoli than the cases of IDC and atypical medullary carcinomas (AMC). Gland formation was absent in the TMC but was common in IDC and AMC. No cytologic differences were noted between IDC and AMC. Nucleoli were larger in TMC (mean 4, microm) than in AMC (mean, 2 microm) and IDC (mean, 1.5 microm). We conclude that lymphocytes and plasma cells may be seen in different types of breast carcinomas and should not be considered a diagnostic feature of TMC. Features potentially helpful in the cytologic differential diagnosis of a carcinoma with prominent lymphoplasmacytic background are nucleolar size (4 microm in MC, vs. 1.5 and 2 microm in IDC and AMC, respectively) and the degree of nuclear atypia. Lymphocytosis may be part of the carcinoma or may originate from a lymph node involved by metastases. In rare cases, a prominent neutrophilic infiltrate may also be present.

Vascular Endothelial Growth Factor Receptor-3 (VEGFR-3): A Marker of Vascular Tumors with Presumed Lymphatic Differentiation, Including Kaposi's Sarcoma, Kaposiform and Dabska-Type Hemangioendotheliomas, and a Subset of Angiosarcomas

Recently, a novel monoclonal antibody to vascular endothelial growth factor receptor 3 (VEGFR-3), a tyrosine kinase receptor expressed almost exclusively by lymphatic endothelium in the adult, has been shown to react with a small number of cases of Kaposi's sarcoma (KS) and cutaneous lymphangiomas. We sought to extend these studies to a large number of well-characterized vascular neoplasms to evaluate diagnostic uses of this antibody and to determine whether it defines them in a thematic fashion. Formalin-fixed, paraffin-embedded sections from 70 vascular tumors were immunostained with antibodies to VEGFR-3 von Willebrand factor (vWF), and CD31. Anti–VEGFR-3 was positive in 23 of 24 KS, 8 of 16 angiosarcomas (AS), 6 of 6 kaposiform hemangioendotheliomas, 4 of 4 Dabska tumors, and 2 of 13 hemangiomas. Positively staining angiosarcomas were characterized either by a prominent lymphocytic component, a hobnail endothelial cell similar to that encountered in the Dabska tumor, or spindled areas resembling KS. No VEGFR-3 expression was noted in any cases of epithelioid hemangioendothelioma, pyogenic granuloma, littoral angioma, or stasis dermatitis. vWF expression was seen in 10 of 13 KS; 13 of 14 AS; 4 of 5 kaposiform hemangioendotheliomas; and all Dabska tumors, hemangiomas, lymphangiomas, epithelioid hemangioendotheliomas, vascular malformations, stasis dermatitis, and splenic littoral angiomas. CD31 expression was present in 12 of 13 KS, 13 of 14 AS, and in all other cases. Expression of VEGFR-3 is a very sensitive marker of KS, kaposiform, and Dabska-type hemangioendotheliomas, suggesting that all show at least partial lymphatic endothelial differentiation. Expression of VEGFR-3 does not reliably discriminate KS from AS. However, the expression of VEGFR-3 by certain AS having Kaposi-like areas, a prominent lymphocytic infiltrate, or hobnail endothelium may define subset(s) having phenotypic, if not pathogenetic and biologic, differences.

Fine-needle aspiration of breast carcinomas with prominent lymphocytic infiltrate

Carcinomas of the breast with prominent lymphoplasmacytic background are commonly encountered in cytology. The aim of this study was to assess the prevalence of different types of carcinomas that share this common feature, identify possible distinguishing cytologic features, and evaluate the diagnostic pitfalls in this group of tumors. Eighteen fine-needle aspirations (FNAs) of breast carcinomas with heavy lymphoplasmacytic background were reviewed. Histologic follow-up was reviewed in all cases. Of 18 cases, there were 9 invasive ductal carcinomas (IDC), and 9 medullary carcinomas (6 typical and 3 atypical). FNAs from typical medullary carcinomas (TMC) showed more severe nuclear atypia and macronucleoli than the cases of IDC and atypical medullary carcinomas (AMC). Gland formation was absent in the TMC but was common in IDC and AMC. No cytologic differences were noted between IDC and AMC. Nucleoli were larger in TMC (mean 4, microm) than in AMC (mean, 2 microm) and IDC (mean, 1.5 microm). We conclude that lymphocytes and plasma cells may be seen in different types of breast carcinomas and should not be considered a diagnostic feature of TMC. Features potentially helpful in the cytologic differential diagnosis of a carcinoma with prominent lymphoplasmacytic background are nucleolar size (4 microm in MC, vs. 1.5 and 2 microm in IDC and AMC, respectively) and the degree of nuclear atypia. Lymphocytosis may be part of the carcinoma or may originate from a lymph node involved by metastases. In rare cases, a prominent neutrophilic infiltrate may also be present.

Cytopathology of high‐grade papillary thyroid carcinomas: Tall‐cell variant, diffuse sclerosing variant, and poorly differentiated papillary carcinoma

Cytologic reports of the aggressive tall-cell and diffuse sclerosing variants of papillary carcinoma have emphasized features such as tall and large cells, increased nuclear size, nuclear pleomorphism, intranuclear pseudoinclusions, three-dimensional tissue fragments, squamous-like cells, and dense inflammatory background as characteristic features. However, the specificity of these features in identifying the particular variants and distinguishing them from other poorly differentiated papillary carcinomas and typical low-grade forms of papillary carcinoma has not been established. The objective of this study was to assess the predictive value of these reported cytologic features. Fourteen cases of high-grade papillary carcinoma consisting of the aggressive variants (tall-cell variant (tcv) and diffuse sclerosing variant (dsv)) and poorly differentiated papillary carcinomas (pdpc) were compared to 18 cases of low-grade papillary carcinoma. Seven cytologic features consisting of the presence of tall and large cells, architectural disorganization, nuclear enlargement, prominent intranuclear pseudoinclusions, nuclear pleomorphism, lymphocytic infiltrate, and squamoid appearance of the neoplastic cells were evaluated. Cytology samples from tcv, dsv, and pdpc consistently demonstrated 3 of the 7 cytologic features (architectural disorganization, nuclear enlargement, and pleomorphism). In contrast, only two of the samples from low-grade cases demonstrated these 3 features. The recognition of these 3 cytologic features had a positive predictive value of 88% and a negative predictive value of 100% for identifying tcv, dsv, and pdpc. The remaining cytologic features were not a consistent feature in the variants, and by cytology alone, distinction between the aggressive variants (dsv and tcv) and pdpc could not be made. Diagn. Cytopathol. 1999;20:19–23. © 1999 Wiley-Liss, Inc.

Lymphocytic Infiltrates in Solitary Parathyroid Adenomas

We describe four cases of solitary parathyroid adenomas with prominent lymphocytic infiltrates presenting as primary hyperparathyroidism. There was no involvement of the other parathyroid glands in the three cases in which they were biopsied. In two cases the thyroids were removed and were without lymphoid infiltrates. The infiltrates were composed of a mixed population of B and T lymphocytes in the three cases that had material available for immunohistochemistry. There was no evidence of parathyroid parenchymal destruction, and in none of the patients was an autoimmune disease present clinically or serologically. We hypothesize that lymphocytic infiltrates in parathyroid adenomas are an uncommon, but clinically innocuous, histologic finding and their presence does not imply an autoimmune disorder.

Lymphoepithelioma-like carcinoma of the uterine cervix: association with Epstein-Barr virus and human papillomavirus.

The presence of Epstein-Barr virus (EBV) has not been documented in previous reports of lymphoepithelioma-like carcinoma (LELC) of the uterine cervix by either polymerase chain reaction or in situ hybridization, and the histogenesis of the tumor remains unknown. Additionally, a relationship between human papillomavirus (HPV) and cervical LELC also has not been reported. In this article, the authors describe the clinical and histopathologic findings for 15 patients with cervical carcinoma that had a histologic pattern of LELC. The polymerase chain reaction detected the presence of EBV and HPV DNA sequences in cervical LELC. All 15 tumors showed a typical syncytial growth pattern of undifferentiated cells with prominent lymphocytic infiltration. The detection rate of the EBV gene sequence in tissue samples from patients with LELC was more frequent than that in control patients with squamous cell carcinoma of the cervix (11 of 15 patients, 73.3%, vs. 4 of 15 patients, 26.7%; P = 0.01). However, the detection rate of HPV-16 and HPV-18 DNA was significantly lower in patients with LELC tumors than in patients with cervical squamous cell carcinoma (3 of 15 patients, 20.0%, vs. 12 of 15 patients, 80.0%; P = 0.001). After a median follow-up of 3.9 years (range, 1.8-5.3 years), the 15 patients showed no evidence of disease or metastasis after radical hysterectomy or radiotherapy. The finding of EBV associations in cervical LELC supports the hypothesis that EBV may be involved in the pathogenesis of tumors that arise in the cervix. It is possible that cervical LELC may follow a different pathway in the pathogenesis of LELC in Asian women as compared with the more common forms of squamous cell carcinoma.

Impact of the Crohn's-like lymphoid reaction on staging of right-sided colon cancer: Results of multivariate analysis

The presence of lymphoid aggregates within the muscularis propria or pericolic fibroadipose tissue apposing invasive colorectal carcinoma, termed the Crohn's-like lymphoid reaction, has been related to improved patient length of survival according to univariate statistical analysis. We tested the Crohn's-like lymphoid reaction as an indicator of prognosis in a multivariate statistical analysis of 344 resected right-sided colonic cancers. Improved 5-year survival in univariate analysis was associated with low tumor grade, regular tubule configuration, expanding tumor growth pattern, prominent peritumoral lymphocytic infiltration, absence of tumoral invasion of extramural veins, all levels of intramural and extramural invasion short of widespread local tumor permeation, conspicuous Crohn's-like lymphoid reaction, and absence of both nodal metastasis and nodal-independent tumor nodules in pericolic fat. By the Cox proportional hazard model using the stepwise method, depth of tumor invasion, lymph node metastasis, Crohn's-like lymphoid reaction, and metastatic tumor nodules in pericolic fat retained independent prognostic significance. Combining the four variables to formulate pathological prognostic categories yielded a highly favorable prognostic group—92% 5-year survival and 95% confidence limits (88% to 96%)—encompassing 53% of the study population. It included all Dukes' stage A carcinomas, 66% of Dukes' stage B adenocarcinomas, and 11% of Dukes' stage C cancers. Lymph node metastases coupled with intramural and extramural extent of tumor invasion are the cornerstones of colorectal cancer staging. Addition of other variables improves prognostication for the cecum and ascending colon. From this study the Crohn's-like lymphoid reaction and metastatic tumor nodules in pericolic fat emerge as significant independent indicators of prognosis for right-sided colon cancer. Complex correlations of both indicators with nonselected variables were observed.

Argyrophilic nucleolar organizer region counts predict survival in thymoma.

The prognosis of thymoma is related mainly to the tumor stage. The prognostic value of argyrophilic nucleolar organizer regions (AgNORs) has been demonstrated in several human neoplasias. Ninety primary thymomas were investigated retrospectively to assess whether AgNOR analysis could offer additional prognostic information. Sections from surgically resected thymomas, routinely fixed in formol and embedded in paraffin, were stained with the argyrophilic method of Ploton. The mean number of AgNORs in the nuclei of 100 tumor cells (AgNOR counts) was calculated for each case. The association between AgNOR counts and survival was assessed by means of uni- and multivariate survival analyses. On univariate analysis, AgNOR counts were associated significantly with 5- and 10-year survival rates (95% and 90%, respectively, for thymomas with 5.58 or fewer AgNORs per cell, but only 55% and 44%, respectively, for tumors with more than 5.58 AgNORs per cell; P < 0.0001). Histologic subtypes of the American classification (P = 0.0006) and clinical stage (P < 0.0001) also were correlated with prognosis. The multivariate survival analysis showed that AgNOR counts (P = 0.001), clinical stage (P < 0.001), and age (P = 0.011) were independent prognostic variables. AgNOR counts were associated with histologic subtypes in the American (P = 0.0001) and European (P = 0.005) classifications and with the clinical stage (P < 0.0001). Moreover, thymoma cells and intermingling lymphocytes showed different numbers of AgNORs and patterns of AgNOR distribution. Analysis of argyrophilic nucleolar organizer regions provides useful prognostic information for patients with thymomas and offers an exact evaluation of the proliferative activity of the neoplastic cells even for thymomas with prominent lymphocytic infiltration.

From dukes through jass: Pathological prognostic indicators in rectal cancer

In the recently described Jass staging system for resected adenocarcinoma of the rectum, peritumoral lymphocytic infiltration and tumor growth pattern are introduced as significant indicators of prognosis in conjunction with depth of tumor invasion and lymph node metastasis. The authors of this study have tested the applicability of the Jass system by reviewing 348 resected rectal cancers for 12 pathological variables, including two newly recognized features, namely the Crohn's-like lymphoid reaction and metastatic tumor nodules in pericolic fat. By univariate analysis improved 5-year survival rate was associated with tubular-type adenocarcinoma, low tumor grade, retention of tubule configuration and nuclear polarity, expanding tumor growth pattern, prominent peritumoral lymphocytic infiltration, absence of extramural vein invasion by tumor, all levels of intramural and extramural invasion short of widespread local tumor dissemination, a Crohn's-like lymphoid reaction pattern, and absence of both nodal metastasis and tumor nodules in perirectal fat. By Cox stepwise proportional hazards analysis, depth of tumor invasion, lymph node metastasis, Crohn's-like lymphoid reaction, and extramural venous invasion retained independent prognostic significance. Peritumoral lymphocytic infiltration and tumor growth pattern of the Jass staging system failed to compete successfully with other variables in the proportional hazards model, in part because of their correlation with the model's selected variables. Both intramural and extramural extent of tumor invasion coupled with lymph node metastasis form the cornerstones of rectal cancer staging. However, other factors do refine prognostication. From this study the Crohn's-like lymphoid reaction emerges as a significant new independent indicator of prognosis for survival from rectal cancer. Although the Crohn's-like lymphoid reaction and extramural vein invasion took precedence as staging variables in this study, a complex interrelationship with other parameters was observed.

Retiform Hemangioendothelioma

Fifteen cases of a distinctive type of low-grade angiosarcoma of the skin are described. Most tumors presented in the second to fourth decades of life, the youngest patient being 9 years old and the oldest 78 (mean age, 36 years). There was no sex predilection. Six tumors arose on the lower limb, four on the upper limb, three on the trunk, and one each on the penis and the scalp. One case arose in the setting of chronic lymphedema and another following radiotherapy for carcinoma of the uterine cervix. Distinctive morphologic features were the presence of long arborizing blood vessels arranged in a retiform pattern (reminiscent of normal rete testis) lined by monomorphic hobnail endothelial cells, a very prominent lymphocytic infiltrate in most cases, and the focal presence of papillae with hyaline collagenous cores, similar to those seen in malignant endovascular papillary angioendothelioma (Dabska's tumor). With a median follow-up of 7.25 years in 14 cases, retiform hemangioendothelioma has proved to be a low-grade neoplasm that recurs frequently but has a very low metastatic rate. The single regional lymph node metastasis in this series was from a case with a biphasic pattern in which only the spindle cell component was represented in the metastasis. There have been no tumor-related deaths, underlining the importance of accurate distinction from conventional angiosarcoma. This distinction is facilitated principally by the absence of dissection between individual collagen bundles and the absence of endothelial atypia or mitotic activity. The precise relationship between retiform hemangioendothelioma and Dabska's tumor is uncertain, possibly because cases of the latter may not be homogeneous.

Solitary Morphea Profunda in a 5‐Year‐Old Girl: Case Report and Review of the Literature

A 5-year-old girl had a solitary sclerotic plaque on the back of recent onset. The histopathologic features were consistent with morphea profunda. Thickening and homogenization of collagen bundles were demonstrated in the dermis and subcutaneous tissues, admixed with a prominent lymphocytic and plasma cell inflammatory infiltrate. Solitary morphea profunda is a variant of localized scleroderma that has not been reported previously in childhood. Cases described in the literature as nodular or keloid morphea may represent a similar entity.

Ultrastructural and Immunohistologic Characterization of Guanethidine-Induced Destruction of Peripheral Sympathetic Neurons

Repeated daily injections of the adrenergic blocking agent guanethidine in high doses (50 mg/kg) to either newborn or adult rats produces a permanent sympathectomy which is thought to involve an immune-mediated mechanism. Ultrastructural examination of the acute phase of guanethidine-induced neuronal degeneration in the superior cervical ganglion demonstrated a prominent lymphocytic infiltrate in the ganglionic parenchyma and perivascular spaces. Within the satelliting cell sheath there were lymphocytes with delicate processes in intimate contact with abnormal or degenerating principal sympathetic neurons. The lymphocytic infiltrate and early evidence of neuronal degeneration developed within three days of onset of treatment and reached a maximum on the 7th day. Immunocytochemical studies of the ganglion demonstrated that the mononuclear infiltrate was composed primarily of CD-8 positive, OX-19 negative lymphocytes, which may represent a natural killer (NK) or NK-like effector cell, as well as scattered monocytes and macrophages. Guanethidine showed little effect on the prevertebral (superior mesenteric and celiac) sympathetic ganglia compared to the paravertebral (superior cervical) chain ganglia of the same animals. Considerable rat strain selectivity was noted with Lewis and Sprague-Dawley strains showing a greater degree of neuronal destruction than Fischer 344 rats. Neonatal thymectomy failed to prevent neuronal degeneration and the lymphocytic infiltrate. These features of immune neuronal killing are not typical of a characterized antibody or T-lymphocyte mediated effector mechanism, but may represent a selective NK cell or NK-like cell mediated pathogenetic pathway. Guanethidine-induced neuronal destruction appears to be a unique type of drug-induced, cell-mediated, autoimmune attack on sympathetic neurons and may provide insight into autoimmune disorders and possibly into diseases characterized by selective neuronal degeneration.

Lymphocytic (“microscopic”) colitis: A comparative histopathologic study with particular reference to collagenous colitis

Lymphocytic colitis, previously termed “microscopic colitis”, is a clinicopathologic syndrome of watery diarrhea, grossly normal colonoscopy, and mucosal inflammatory changes. Since lymphocytic colitis is a new, incompletely characterized entity, a histopathologic study was performed to compare lymphocytic colitis (n = 16), collagenous colitis (n = 17), idiopathic inflammatory bowel disease (n = 16), acute colitis (n = 16), and histologically normal colon (n = 12). The study was a blinded semiquantitative analysis of histologic features in the surface epithelium, lamina propria, and crypts. The most distinctive feature of lymphocytic colitis was increased intraepithelial lymphocytes, particularly in the surface epithelium ( P = .0001 v idiopathic inflammatory bowel disease, acute colitis, and normal colon). Other prominent features of lymphocytic colitis included surface epithelial damage ( P < .005 v diopathic inflammatory bowel disease and normal colon), increased lamina propria chronic inflammation ( P < .01 v normal), and minimal crypt distortion or active cryptitis. There were striking similarities between lymphocytic colitis and collagenous colitis, but subepithelial collagen thickening was seen only in collagenous colitis. Idiopathic inflammatory bowel disease showed prominent crypt distortion and greater active inflammation, in addition to minimal intraepithelial lymphocytes. Acute colitis occasionally demonstrated prominent surface epithelial damage, but was otherwise dissimilar from lymphocytic colitis. We reached the following conclusions: (1) the entity “microscopic colitis” shows characteristic histopathology including prominent lymphocytic infiltration of epithelium, and thus, a more appropriate designation is lymphocytic colitis; (2) although lymphocytic colitis closely resembles collagenous colitis, each entity is distinct on biopsy; and (3) lymphocytic colitis is readily distinguishable from idiopathic inflammatory bowel disease, acute forms of colitis, and normal colorectum.

Gene amplification in malignant human gliomas: clinical and histopathologic aspects.

Gene amplification occurs in 45-50% of malignant human gliomas (MHG). In the present study, 64 genetically characterized gliomas were evaluated to determine if tumors with amplification of the epidermal growth factor receptor (EGFR), N-myc, c-myc, or gli genes had distinctive histopathologic features. There was no significant difference in age (p = 0.10) or gender (p = 0.78) between patients whose tumors contained amplified genes and those whose tumors did not exhibit this characteristic. Although the patients with amplified genes in their tumors survived slightly longer than patients whose tumors had no detectable gene amplification, these differences were not statistically significant (p = 0.21). The 28 tumors with amplification included 24/48 (50%) glioblastoma multiforme, 2/6 (33%) anaplastic astrocytomas and 2/5 (40%) gliosarcomas. No amplification was seen in one oligodendroglioma, three anaplastic mixed gliomas or one giant cell glioblastoma multiforme. Necrosis and endothelial proliferation were equally prevalent among tumors with and without amplification. Comparison of tumors with gene amplification and tumors without this characteristic revealed similar distributions of most morphologic cells types. Although prominent perivascular lymphocytic infiltrates were more frequent in tumors without amplification, this association was of borderline significance statistically. In situ hybridization of tumors with amplification using an EGFR mRNA probe showed intense labeling of different neoplastic cell types including fibrillary and protoplasmic astrocytes, gemistocytes, anaplastic cells, and multinucleated giant cells. Non-neoplastic cells such as hyperplastic endothelium within the tumors did not express detectable EGFR mRNA. These studies demonstrate that (a) cells with quite different morphology within the same tumor can contain the same genetic alteration; (b) tumors of identical histological appearance may have arisen and evolved by different molecular mechanisms; and (c) molecular analyses are necessary to evaluate gene amplification in MHG since this characteristic cannot be accurately predicted by the morphologic or clinical criteria used in this study.

Heterogeneity of Epithelial Cells and Reactive Components in Thymomas: An Ultrastructural and Immunohistochemical Study

Fourteen thymomas were studied by electron microscopy and immunohistochemistry. Based on the ultrastructure of the neoplastic epithelial cells in comparison with normal thymic epithelium, four cortical-, three mixed-, five medullary-, and two corpuscular-type tumors were categorized. Histologically the tumors of cortical type showed prominent lymphocytic infiltration, but scant interdigitating reticulum cells (IDCs) were demonstrated by immunoperoxidase method on paraffin sections with anti-S-100 protein antiserum. Fewer lymphocytes but more IDCs were present in the tumors of medullary and corpuscular types, although variable in those of mixed type. This corticomedullary difference among thymomas was confirmed in some of them by the immunoperoxidase method on frozen sections with monoclonal antibodies. The cortical-type tumors were HLA-DR positive in tumor cells and infiltrated predominantly with cortical thymocytes (OKT-6+, OKT-3-, both Leu 3a/3b+ and OKT-8+), whereas the medullary- and corpuscular-type tumors were HLA-DR positive primarily in IDCs but not in tumor cells and were infiltrated more with medullary thymocytes (OKT-6-, OKT-3+, either Leu 3a/3b+ or OKT-8+). The classification of thymomas based on neoplastic epithelial cells will serve to refine the traditional classification based on reactive lymphocytes.

Quantitative and functional study of lymphoid cells infiltrating solid tumors

Lymphocytes are a frequent component of inflammatory infiltrates that characteristically are present in certain human neoplasms. Although inflammatory cells may be sparse in spontaneously arising tumors, solid tumors such as carcinomas of the breast, lung, germinal-cell tumors, malignant melanoma, and primary liver cancer are characterized by a prominent lymphocytic infiltrate (12). The presence of inflammatory cells in and around tumors is a favorable prognostic sign in at least some tumors, and because of that, numerous analyses of the lymphoid cells in situ have been attempted in recent years. Still, the nature and function of mononuclear cells in tumors remain unclear, as does the precise relationship between mononuclear cell infiltrates and tumor growth. It is believed that certain of these infiltrating lymphoid cells sensitized to tumor antigens mediate lysis of tumor cells (i.e., cytotoxic T lymphocytes; CTL). Other lymphoid cells may mediate tumor-cell lysis in a nonspecific