Strong triaxial coupling and anomalous Poisson effect in collagen networks

While cells within tissues generate and sense 3D states of strain, the current understanding of the mechanics of fibrous extracellular matrices (ECMs) stems mainly from uniaxial, biaxial, and shear tests. Here, we demonstrate that the multiaxial deformations of fiber networks in 3D cannot be inferred solely based on these tests. The interdependence of the three principal strains gives rise to anomalous ratios of biaxial to uniaxial stiffness between 8 and 9 and apparent Poisson's ratios larger than 1. These observations are explained using a microstructural network model and a coarse-grained constitutive framework that predicts the network Poisson effect and stress-strain responses in uniaxial, biaxial, and triaxial modes of deformation as a function of the microstructural properties of the network, including fiber mechanics and pore size of the network. Using this theoretical approach, we found that accounting for the Poisson effect leads to a 100-fold increase in the perceived elastic stiffness of thin collagen samples in extension tests, reconciling the seemingly disparate measurements of the stiffness of collagen networks using different methods. We applied our framework to study the formation of fiber tracts induced by cellular forces. In vitro experiments with low-density networks showed that the anomalous Poisson effect facilitates higher densification of fibrous tracts, associated with the invasion of cancerous acinar cells. The approach developed here can be used to model the evolving mechanics of ECM during cancer invasion and fibrosis.

Intraductal Carcinoma of the Prostate Gland: Recent Advances

Intraductal carcinoma of the prostate (IDC-P) is characterized by prostatic carcinoma involving ducts and/or acini. The presence of IDC-P is usually associated with a high-grade Gleason score, large tumor volume, and adverse prognostic parameters, including extraprostatic extension and seminal vesicle invasion. When present, IDC-P is associated with worse outcomes, regardless of treatment status. IDC-P is included in a broader diagnostic category of atypical cribriform lesions of the prostate gland. This category of lesions also includes high-grade prostatic intraepithelial neoplasia (HGPIN), urothelial carcinoma involving prostatic ducts or acini, and prostatic ductal adenocarcinoma, amongst other intraductal proliferations. Differentiating between these entities is important as they have differing therapeutic and prognostic implications for patients, although differential diagnosis thereof is not always straightforward. The present review discusses IDC-P in regards to its morphological characteristics, molecular features, and clinical outcomes. Given the current state of knowledge, the presence of IDC-P should be evaluated and documented correctly in both radical prostatectomy and needle biopsy specimens, and the clinical implications thereof should be taken into consideration during treatment and follow up.

Expression of SOX10 in Salivary Gland Oncocytic Neoplasms: A Review and a Comparative Analysis with Other Immunohistochemical Markers

OBJECTIVES

We evaluated SOX10 (SRY-related HMG-box 10) in differentiating acinic cell carcinoma (AciCC) from other salivary gland neoplasms with oncocytic features on fine-needle aspiration cell blocks (FNA CB) and compared its performance to DOG1 (discovered on gastrointestinal stromal tumor 1).

MATERIAL AND METHODS

35 FNA CB of oncocytic salivary gland neoplasms, i.e. 13 cases of AciCC, 16 of Warthin tumor (WT), 3 of mucoepidermoid carcinoma (MEC) and 3 of oncocytoma (ONC), and 75 salivary gland resections, i.e. 26 AciCC, 7 WT, 36 MEC, 3 ONC, 2 mammary analog secretory carcinomas (MASC) and 1 papillary cystadenoma were stained for SOX10 and DOG1.

RESULTS

None of the benign oncocytic neoplasms were immunoreactive for SOX10 on CB or resection, similar to DOG1. On CB, 61.5 and 77% of AciCC were positive for SOX10 and DOG1, respectively. All surgically resected AciCC cases were positive for SOX10 and DOG1; other malignant oncocytic lesions such as MEC and MASC demonstrated variable SOX10 and DOG1 staining.

CONCLUSION

The use of SOX10 may increase the diagnostic accuracy of oncocytic lesions on FNA. In this context, SOX10 is equivalent to DOG1 in ruling out benign lesions such as WT and ONC; however, negative results for SOX10 as well as DOG1 do not favor a benign diagnosis since MEC is often negative for both markers.

The profile of acinic cell carcinoma after recognition of mammary analog secretory carcinoma

To determine the influence of the newly described mammary analog secretory carcinoma (MASC) with ETV6 translocation on our understanding of salivary acinic cell carcinoma (AciCC), we reviewed 81 cases of AciCC: 64 "classic" AciCCs, 11 AciCCs with high-grade transformation (HGT), and 17 zymogen granule poor AciCCs. ETV6 fluorescence in situ hybridization revealed that classic AciCC (7 of 7 tested) and AciCC-HGT (4 of 4 tested) have intact ETV6. However, 10 of 17 zymogen granule poor AciCCs showed ETV6 translocation and were reclassified as MASC; the diagnosis of AciCC was retained for cases with intact ETV6. MASCs were distinguished by the lack of zymogen granules, mucin production, and stronger S100 reactivity. MASC showed a striking male predilection (male-to-female ratio, 8:2) in contrast to AciCC (male-to-female ratio, 1:1.5; P<0.01). Compared with cases of confirmed AciCC, AciCC-HGT occurred in older patients (mean age of 66.2 y vs. 47.7 y, P=0.007) and showed a poorer mean overall survival [40.2 mo (95% confidence interval (CI), 7.5-73 mo) vs. 125 mo (95% CI: 98-151 mo); P<0.001]. Patients with confirmed AciCC without HGT showed a recurrence rate of 15% (9/60) and a 7.9% (3/38) incidence of regional lymph node involvement. It appears that more than half of zymogen granule poor AciCCs are likely to represent MASC. Even after excluding cases of MASC, the presence of HGT in AciCC predicts poorer overall survival.

Occult Primary Parotid Gland Acinic Cell Adenocarcinoma Presenting With Extensive Lung Metastasis

Acinic cell adenocarcinoma is a malignant salivary gland neoplasm with a relatively low rate of lymphangitic spread to regional lymph nodes. Distant metastases are rare and their occurrence typically indicates an unfavorable outcome. We encountered an unusual example of acinic cell adenocarcinoma that initially presented in the lung, whereas the primary parotid carcinoma, despite extensive clinical evaluation, only became apparent 1 year after initial diagnosis. The histologic, immunohistochemical, and ultrastructural features of the tumor in the parotid gland and lung were similar. The tumor displayed an aggressive behavior resulting in death within 2 years of the initial presentation. This presentation is unique, showing that peripheral lung tumors of salivary gland type are likely to be metastatic, and careful clinical evaluation is warranted in establishing their primary site of origin.

Intraductal and papillary variants of acinar cell carcinomas: a new addition to the challenging differential diagnosis of intraductal neoplasms

The recognition and differential diagnosis of pancreatic intraductal neoplasms (IN) have gained importance in the past few years, as the incidence of these tumors (especially intraductal papillary mucinous neoplasms-IPMNs) have risen to >10% of pancreatic resections, and their significance as precursors of invasive cancer is better appreciated. Acinar cell carcinomas (ACCs) are typically solid tumors; however, we have recently encountered 7 ACCs with either intraductal growth and/or a papillary/papillocystic pattern that could be mistaken for IN. The clinicopathologic features of these cases were studied. Four patients were male and 3 female, with a mean age of 59 and mean tumor size of 4.9 cm (as compared with 10 cm in conventional ACCs). Only 1 patient had metastasis at the time of diagnosis (as opposed to 50% in usual ACCs). In 5 cases, the tumors had nodular growth of sheet-forming acinar cells, some of which were within ducts, as evidenced by the polypoid nature of the process, partial ductal lining, and presence of small tributary ducts in the walls. In 3 cases, the tumor had papillary and/or papillocystic growth, at least focally. All cases had cystic areas. No mucin was identified. All expressed trypsin. Markers of ductal differentiation were either absent or focal. A minor endocrine component was present in 3. The main histologic findings that distinguished these tumors from IPMNs were the more sheetlike nature of the nodules (rather than villous or arborizing papillae), cuboidal cells, overall basophilia of the cytoplasm, prominent nucleoli, apical granules, intraluminal crystals or pale, acidophilic secretions (enzymatic condensations), and lack of mucin. In conclusion, some ACCs show intraductal growth or exhibit papillary patterns, which can mimic IN, especially IPMNs. In such cases, attention to morphologic details described above, and immunohistochemistry are helpful. The clinical significance of this variant is difficult to determine; however, it appears that the tumors are relatively small and metastasis at presentation is less common than typically seen in ACCs (1/7 vs. 50%).

Recurring acinic cell carcinoma of the buccal mucosa: a case report

A case of acinic cell adenocarcinoma of the left facial area of 10-years' duration in a 29-year-old man is presented. The patient reported surgical resection of a nodular lesion in the left buccal mucosa 8 years earlier in another hospital. Since then, the lesion recurred 3 times within 2 years. The first lesion and 2 recurrent ones were surgically removed. With the third recurrent lesion, the patient did not return promptly for treatment and was directed to our clinic after 6 years. The clinical, tomographic, immunohistochemical, and therapeutic aspects are analyzed.

Nonductal neoplasms of the pancreas

Although the majority of pancreatic neoplasms are infiltrating ductal adenocarcinomas or other neoplasms with ductal differentiation, neoplasms with acinar, endocrine, mixed, or uncertain differentiation constitute a diverse and distinctive group. The most common and best-characterized nonductal neoplasms are pancreatic endocrine neoplasm, acinar cell carcinoma, pancreatoblastoma, and solid pseudopapillary neoplasm. This review details the clinical and pathologic features of these nonductal neoplasms, highlighting diagnostic criteria including the use of specific immunohistochemical stains to define the cellular differentiation of the neoplasms.

Immunophenotypical profiles of salivary gland tumours: a new evidence for their histogenetic origin

The histogenetic origin of salivary gland tumours is not clear. In normal tissues smooth muscle actin (SMA) is expressed in myoepithelial cells, CK14 immunoreactivity is seen in myoepithelial and basal cells and CK10 in keratinized squamous epithelium. In this study, we examine the immunophenotypic properties of salivary gland tumours in order to obtain further insight into their histogenesis. 30 cases of salivary gland tumours (18 pleomorphic adenomas, 8 Warthin's tumours, 2 basal cell adenomas, 2 acinic cell carcinomas) were included in our study. Cytokeratin (CK) 10, CKI4, CKI7, CK18, CK 19, and smooth muscle actin (SMA) immunostains were applied to the sections. Immunoreactivities were detected and the statistical significance was evaluated by chi square test. SMA was not detected in Warthin's tumour (p < 0.0001). CK14 was found in all tumours except acinic cell carcinomas (p < 0.0001). CK10 immunoreactivity was observed in 5 Warthin's tumour. In conclusion, pleomorphic adenomas and basal cells adenomas originate from stem cells. Immunophenotypic profile of Warthin's tumour is suggestive of an embryological remnant origin.

Cytology of pancreatic acinar cell carcinoma

Acinar cell carcinoma (ACC) of the pancreas is extremely uncommon and its cytologic features have rarely been described. We describe the cytologic features of cases we have seen, review the literature regarding its cytologic features and discuss the pitfalls that may be encountered and the use of immunohistochemistry for its diagnosis. We searched our databases for all cases of histologically confirmed pancreatic ACC which had undergone prior fine needle aspiration (FNA) of the primary pancreatic lesion. The clinical histories, radiographic and sonographic findings, cytologic features, original cytologic diagnoses, and final histologic diagnoses were reviewed. Four cases of pancreatic ACC were found that had undergone FNA prior to histologic confirmation of the diagnoses. They were from 2 men and 2 women aged 50-75 yr. All masses were in the head of the pancreas, 2 had apparent peri-pancreatic adenopathy and 1 had an apparent liver metastasis. On review, all 4 had had diagnostic material on cytology samples. Original cytologic diagnoses included "acinar cell carcinoma," "pancreatic endocrine tumor," "favor neuroendocrine tumor, low-grade" and "non-diagnostic specimen." The cytologic features included small to moderate-sized loose groups with numerous single cells, prominent acinar formation, little anisonucleosis and prominent nucleoli. The cytologic features showed significant overlap with those of pancreatic endocrine tumors.

Intracranial extension of acinic cell carcinoma of the parotid gland

We report the case of a 47-year-old woman who experienced multiple recurrences of acinic cell carcinoma, lung metastasis, and intracranial extension of the tumor during a 32-year period. In this report, the clinical, microscopic, histochemical, and electron microscopy features of this acinic cell carcinoma are described, and a review of published information about this neoplasm is presented.

Acinar cell cystadenocarcinoma of the pancreas: Report of rare case and review of the literature

Most exocrine pancreatic tumors are of ductal origin, whereas acinar cell adenocarcinomas are unusual (1% to 2% of all exocrine pancreatic neoplasms). We recently found a cystic adenocarcinoma of the pancreatic body whose cells had the characteristics of acinar cells, which we term acinar cell cystadenocarcinoma. Macroscopically, this tumor consists of a large multilocular cystic mass with a pseudocapsule and a spongy appearance on the cut surface. Microscopically, the cysts are lined by a single layer of cuboid/columnar cells. The cytoplasm has the characteristics of acinar cells, with eosinophilic granules in the apex and prominent nucleoli. Immunohistochemically, the cells express alpha1-antitrypsin, trypsin, and lipase in their cytoplasm, thus confirming the acinar origin of the tumor. A review of the literature revealed only 5 other cases of this tumor reported since its first description in 1981. Follow-up data are available for 4 of these; all of the affected patients had metastases at presentation or a few months later, and 2 died of the disease, at 13 and 37 months after diagnosis. Although this variant of adenocarcinoma of the pancreas is not prognostically different from the classic solid type (few patients survive more than 5 years), we believe that it is important because of its extreme rarity.

Acinic cell carcinoma with follicular pattern of the soft palate

Acinic cell carcinoma (ACC) is an uncommon low-grade malignancy of the salivary glands. Most cases occur in the major salivary gland, but a few cases affecting the minor salivary gland have also been described. Although various growth patterns have been reported in the literature, a few cases have been diagnosed as ACC with follicular pattern. We present a rare case of ACC with follicular pattern of the soft palate in a 60-year-old man. The occurrence of ACC in this area is extremely rare, and its striking thyroid-like appearance may cause confusion in the differential diagnosis.

Acinar cell carcinoma arising in the stomach: a case report with literature review

Acinar cell carcinomas (ACCs) are uncommon malignant tumors of the exocrine pancreas, constituting 1% to 2% of all nonendocrine pancreatic neoplasms. Cases of acinar cell carcinoma developing in heterotopic pancreatic tissue are extremely rare. To the best of our knowledge, no cases of primary ACC developing in the stomach have been reported in the literature. We report the first case of a primary ACC arising in the stomach in an 86-year-old female who presented with a 5-cm gastric submucosal mass with superficial ulceration and a history of anemia. The neoplasm exhibited typical acinar morphology. Immunohistochemical studies demonstrated strong positive reactivity for antitrypsin and antichymotrypsin, and electron microscopy confirmed the presence of zymogen granules. A complete metastatic workup failed to identify any primary pancreatic tumor or other nonpancreatic tumor.

Combined typical carcinoid and acinic cell tumor of the lung: a heretofore unreported occurrence

We report a primary combined typical carcinoid and acinic tumor of the lung in a 70-year-old man. Although a similar case was reported previously, to the best of our knowledge this is the first case in which the diagnosis is supported by both immunohistochemical and ultrastructural findings. We review the literature and discuss the implications of this finding.

Pancreatic acinar cell carcinoma

Acinar cell carcinomas (ACCs) are rare neoplasms that represent less than 2% of all exocrine tumors of the pancreas. Although they occur more often in adults between the 5th and 7th decades of life, a few cases have been reported in children. Histologically, ACCs can resemble islet cell tumors, but they differ in their ultrastructural and immunohistochemical features. Although ACCs present a bland histology, they are highly malignant and the survival of patients with these tumors, even though better than that of those with ductal cell carcinomas, is generally poor.

Acinic cell carcinoma of the breast: an immunohistochemical and ultrastructural study

The clinicopathological features of six cases of breast carcinomas showing features of acinic cell differentiation, which are similar to those seen in homologous tumors of salivary glands, are presented. The patients, all women, were 35-80 years of age. One case recurred after 4 years, and in two cases axillary lymph node metastases were found at the time of surgery. Histologically the tumors showed a microglandular pattern merging with solid areas. Cytologically, immunohistochemically, and ultrastructurally the tumors were very similar to cases of acinic cell carcinoma of the parotid gland. The differential diagnostic criteria with microglandular adenosis and carcinomas showing granular cytoplasm are discussed. It seems that acinic cell carcinomas of the breast have to be added to the long list of tumors that affect the salivary glands and can also arise in the breast.

Atypical acinar proliferations of the prostate

Small acinar lesions of the prostate may mimic prostate cancer. In the central and transition zone of the prostate, atypical adenomatous hyperplasia (AAH) must be differentiated from low grade carcinoma (Gleason score 2-5). In the dorso-peripheral zone, high grade prostatic intraepithelial neoplasia (PIN) and atypical small acinar proliferations (ASAP) are the most important lesions mimicking carcinoma. Further differentiation is necessary between high grade PIN and intraductal carcinoma. ASAP, on the other hand, may mimic low grade carcinoma. The significance of basal cell type cytokeratin immunohistochemistry (IHC) in the differentiation between ASAP and low grade carcinoma of the prostate was substantiated by additional MIB-1 IHC. The status of the basal cell layer in ASAP was found to be variable (complete, fragmented and absent). Independent of the status of the basal cell layer, the mean MIB-1 proliferation index of ASAP was significantly higher than that of clearly benign lesions and did not differ from that of low grade carcinoma. As carcinoma is frequently detected in rebiopsies, close clinical follow up of patients with ASAP is advisable.

Unilateral aneuploid dedifferentiated acinic cell carcinoma associated with bilateral-low grade diploid acinic cell carcinoma of the parotid gland

A dedifferentiated acinic cell carcinoma (AciCC) of the right parotid gland with lymph node metastases occurred in a 36-year-old woman. The tumour was associated with a bilateral well-differentiated AciCC. The two components of this tumour had different (high and low) proliferative activity measured by Mib-1 and different (aneuploid and diploid) DNA content. Despite the presence of a high-grade component, TP53 mutations, microsatellite instability (MSI) and/or loss of heterozygosity (LOH) at the p53 locus were not detected. Although the follow-up of the patient is very short, the aggressiveness of the tumour is shown by a recurrence in the right parotid within 4 months and by the rapid development of regional metastases.

Signaling pathways via NK1 receptors and their desensitization in an AR42J cell line

Substance P (SP) has been shown to induce phosphatidylinositol (PI) hydrolysis and Ca2+ mobilization in AR42J cells. In this study, we confirmed the expression of NK1 but not NK2 or NK3 receptors in this cell line, and further investigated signaling pathways via NK1 receptors and their desensitization. The activation of NK1 receptors by SP affected neither basal cyclic AMP level nor cyclic AMP accumulation induced by secretin and forskolin, although it stimulated PI hydrolysis. Furthermore, SP induced Ca2+ mobilization even in the absence of extracellular Ca2+, though maximal response was reduced. U73122, a phospholipase C (PLC) inhibitor, nearly abolished Ca2+ response to SP. In addition, SP-induced Ca2+ signaling and PI hydrolysis rapidly desensitized following short exposure to SP, which did not affect the Ca2+ amount in intracellular Ca2+ stores or Ca2+ responses to carbachol and gastrin releasing peptide-10. These findings suggested that NK1 receptors do not couple to adenylate cyclase, although they induce PI response, and that NK1 receptors induce both intracellular Ca2+ release and Ca2+ influx through PLC activation. Ca2+ signaling and PI hydrolysis through NK1 receptors desensitized rapidly after the stimulation, maybe dependent on the modification of NK1 receptors.

Clear cell tumors of the lower respiratory tract

Clear cell tumors of the lower respiratory tract comprise a diverse group of lesions. The prototypical lesion is the benign clear cell tumor or "sugar tumor," a tumor of enigmatic histogenesis, whose name derives from the high glycogen content of the cells. Analogous to the salivary gland lesion of the same name, acinic cell tumors may also occur in the tracheobroncheal tree. The topic of "clear cell carcinoma" is discussed, which in the opinion of the authors does not constitute a distinct tumor entity. A discussion of potential lesion metastatic to the lung with clear cell histology is also presented. Histological details of the various entities are discussed, as well as the significant histochemical, immunohistological, and electron microscopic features; in particular, such findings that are relevant to differential diagnosis are stressed, including the distinction of primary and metastatic lesions.

Immunohistochemical study of acinic cell carcinoma of minor salivary gland

Acinic cell carcinoma (ACC) is a rare salivary gland tumour, making up 4% of all minor salivary gland tumors. Typically, it is composed of acinic cells although transitional and duct-like cells are also identified. In the present study, a panel of antibodies was applied to eight minor salivary gland ACCs. Antibodies tested were: cytokeratins 7, 8, 13, 14, 18, 19, vimentin and actin (HHF35). Immunohistochemical staining revealed that cytokeratin 8, among the tested antibodies, was the more specific to neoplastic cells with a pattern of distribution quite variable and peculiar. This staining may be useful in the recognition of neoplastic acinic cells.

Comparative cytologic features of pancreatic acinar cell carcinoma and islet cell tumor

Acinar cell carcinoma (ACC) and islet cell tumor (ICT), both rare pancreatic neoplasms, can be diagnosed accurately and rapidly with the use of imaging-guided fine-needle aspiration biopsies. The specific cytologic features of these tumors are described in a series of 17 patients, and histologic and immunocytochemical correlations are discussed. Important cytologic findings in ACC are loosely cohesive clusters with cells having uniform nuclei and prominent nucleoli, cytoplasm is finely granular and eosinophilic. Islet cell tumors show many single cells, occasional rosettes, uniform nuclei, sometimes binucleate, dense basophilic cytoplasm. Chromogranin is often positive (80%) in ICT. Trypsin and chymotrypsin were often positive (71%) in ACC. Histology was confirmatory in all cytology cases. The recognition of cytologic features in conjunction with immunocytochemical studies can increase the diagnostic sensitivity for these two rare tumors.

Potential utility of p53 immunopositivity in differentiation of adenocarcinomas from reactive epithelial atypias of the lung

Reactive atypia of alveolar epithelium occurs in many types of lung injury and may sometimes raise suspicions of adenocarcinoma or bronchioloalveolar carcinoma. To assess whether there is sufficient difference in the frequency of p53 protein immunopositivity in these lesions to provide a practical basis for differentiating malignancy from reactive atypia, we immunostained 110 malignant and inflammatory/fibrotic lung specimens for p53 protein. Paraffin-embedded sections were immunostained with p53 protein antibody (clone BP53-12; BioGenex, San Ramon, CA) and standard capillary gap (Microprobe; Fisher Scientific, Fairlawn, NJ) avidin- biotin complex technique with antigen retrieval solution. Percent of immunopositive cells was semiquantitatively categorized as follows: 0%, less than 1%, 1% to 10%, 10% to 50%, more than 50%. Of reactive atypias, 94% are negative or show p53 immunopositivity in less than 10% of cells. Of p53 positive malignancies, 86% are positive in more than 10% of cells. When p53 immunopositivity occurs in more than 10% of atypical cells, the lesion is usually a malignancy, primarily adenocarcinoma. Most reactive atypias are immunopositive in less than 10% of atypical cells. Important caveats were noted. Rare reactive atypias are p53 immunopositive in greater than 10% of cells. Bronchioloalveolar carcinomas are infrequently p53 immunopositive. Therefore, this approach would be less useful in their differentiation from reactive atypias.

Proliferating patterns of salivary gland adenocarcinomas with the use of PCNA labeling

Cellular proliferation activity in a series of salivary gland malignant tumors was evaluated using the index of proliferation cellular nuclear antigen (PCNA) immunoreactivity. A streptavidin-biotin immunoperoxidase method (ABC) using a monoclonal antibody PC10 demonstrated nuclear staining with varying intensity and distribution in all tumor specimens. Acinic cell carcinoma (n = 5) and polymorphous low-grade adenocarcinoma (n = 1) showed relatively low proliferation fractions. In adenoid cystic carcinoma (n = 13), PCNA-positive nuclei were mainly distributed in neoplastic myoepithelial cells which were the predominant cells in tumor growth. No statistically significant difference was found between cribriformtubular and solid subtypes. In adenocarcinoma (n = 6), a well differentiated papillary-cystic pattern expressed a significantly higher PCNA index than poorly differentiated solid pattern, showing the loss of the relationship between PCNA expression and differentiation. Tumor cell differentiation appears to be more important than proliferation in determining biological behavior and prognosis.

Acinic cell-like carcinoma of the breast

A case of infiltrating carcinoma of the breast with features similar to those seen in acinic cell carcinoma of the parotid gland is described in a 42-year-old woman. The neoplastic cells were immunoreactive with anti-lysozyme- and anti-salivary-type amylase antisera and contained electron-dense cytoplasmic globules similar to those seen in acinic cell carcinoma of salivary glands. One lymph node out of 18 was found to contain a metastatic deposit. The patient is alive and well 1 year after mastectomy. This appears to be the first case of carcinoma with acinic cell-like features reported in the breast.

Filamentous inclusions in nonneoplastic and neoplastic pancreas: an ultrastructural and immunogold labeling study

Filamentous inclusions (FI) are unusual, irregularly shaped cytoplasmic inclusions, which are mostly found in acinar cell carcinomas of the pancreas and are consequently thought to be an abnormal zymogen granule type. This study describes identical inclusions in acinar, centroacinar, and small duct epithelial cells from nonneoplastic pancreas, as well as those found in tumor cells from a mixed acinar-endocrine pancreatic carcinoma. An ultrastructural and immunogold labeling demonstration indicates that these inclusions are aggregates of intermediate filaments immunoreacting with the anti-cytokeratin AE1/AE3 mixture and with V9 clone anti-vimentin monoclonal antibodies. Their pleomorphic appearance, variable immunoreactivity, and frequent association with lipid droplets and secondary lysosomes, mostly of the angulate type, led to the hypothesis that the FI undergo a degenerative remodeling pathway similar to that proposed for hepatic Mallory bodies. A survey of the literature on FI and human tumors suggests that they are a variably expressed ultrastructural feature of tumor cells originating from exocrine cell-containing tissues, namely the pancreas and gastrointestinal tract.

Unusual intracytoplasmic inclusions in metastatic carcinoma. Discussion of their possible significance

Unusual filamentous inclusion bodies in the cytoplasm of metastatic tumor cells are described. Their presence (intermingled with zymogen granules) seems rather restricted to cells of primary or metastatic acinar cell carcinoma of the pancreas, acinic carcinoma of salivary gland (parotid gland) and Paneth cells (neoplastic or in zinc deficiency state). For the time being, the real nature of these inclusions (deranged zymogen granules?) is unclear. This case also emphasizes the value of electron microscopy in solving the problem of the occult primary tumor and avoiding the misdiagnosis of an endocrine tumor (e.g. islet cell tumor or carcinoid), or a duct cell tumor with eosinophilic granular cytoplasm or in recognizing the foci of acinar cells in a mixed variant of carcinoma of the pancreas.

Advanced prostate cancer with normal serum prostate-specific antigen values

Prostate-specific antigen is a specific and sensitive marker of prostate cancer, and most patients with advanced prostate cancer have elevated serum prostate-specific antigen values. Over a period of 45 months, 976 cases of advanced prostate cancer (stages C and D) were investigated to determine the serum prostate-specific antigen level at presentation. Eight cases of advanced prostate cancer are documented in which the serum prostate-specific antigen values were within normal limits. Six of the eight cases showed the features of invasive moderately differentiated acinar carcinoma; one case of small-cell carcinoma and one of cribriform carcinoma were noted. Direct immunohistochemical assessment of tumor tissue was performed, and the correlation between monoclonal and polyclonal antibody staining was assessed. In seven of the eight cases, monoclonal antibodies showed no convincing staining, while all but one (small cell) were positive for polyclonal stains.

Pancreatoblastoma in an adult: its separation from acinar cell carcinoma

Pancreatoblastomas are rare tumours, which usually occur in childhood. Here we describe a pancreatoblastoma in a 39-year-old woman. The tumour was located in the tail of the pancreas and consisted of cells forming well-differentiated acinar structures and scattered solid components ("squamoid corpuscles"). Immunocytochemically, the acinar components were positive for pancreatic enzymes and pancreatic stone protein, while the cells of the "squamoid corpuscles" lacked these markers. There was no p53 overexpression nor any mutation at codon 12 of the Ki-ras oncogene. The main differential diagnosis of this tumour was acinar cell carcinoma, because both tumours have a number of features in common (scattered solid components, positivity for pancreatic enzymes, lack of p53 overexpression and of Ki-ras mutation). Findings which distinguished the pancreatoblastoma and separated it from acinar cell carcinoma were the negativity of the solid components ("squamoid corpuscles") for neuroendocrine markers and their very weak keratin positivity. As the patient is alive and well 30 months after tumour resection, this pancreatoblastoma also differs in biology from the usual acinar cell carcinoma.

Intermediate filaments in rat pancreatic acinar tumors, human ductal carcinomas, and other gastrointestinal malignancies

BACKGROUND/AIMS

Keratin is a member of the intermediate filament family in epithelial cells. Two-dimensional gel electrophoresis of different epithelial cells has shown 20 different keratin polypeptides. Therefore, mapping of the keratin polypeptides can be used to define a specific tissue.

METHODS

Cytokeratin expression was investigated by using monoclonal antibodies in human surgical specimens and autopsy material of pancreatic, gastric, liver, and colon carcinomas and cholangiocarcinomas, and their metastasis to lymph nodes and liver was examined. In addition, rat acinar cell carcinomas were used to compare cytokeratin expression in ductal vs. acinar cell pancreatic carcinomas.

RESULTS

Human pancreatic ductal carcinomas expressed keratins 7, 8, 18, and 19, whereas the majority of rat acinar carcinomas did not express keratins typical for ducts in rat pancreas. The keratin patterns of gastric and colon carcinomas were identical with keratins 8, 18, and 19. In contrast, hepatocellular carcinomas expressed the same keratin pattern as pancreatic acinar carcinomas with keratins 8 and 18, whereas cholangiocarcinomas expressed keratin 7, 8, 18, and 19, similar to pancreatic ductal carcinomas. Metastasis of pancreatic ductal and colon carcinomas retained their keratin patterns.

CONCLUSIONS

Keratin polypeptide typing of unknown malignant cells can be a useful tool for cell identification.

Expression of p53 protein in prostate cancers of different histologic types

Mutations and overexpression of p53 gene in prostate carcinoma have been found but their significance in the development and progression of cancer is so far unknown. We investigated the prevalence of abnormalities of p53 protein in a heterogeneous group of prostate carcinoma to verify whether acinar and non acinar carcinomas have a different expression of p53 protein. Paraffin sections of 45 prostate carcinomas (39 acinar, 3 ductal papillary, 1 transitional cell, 1 mucinous and 1 pure small cell) were examined for the expression of p53 protein using a panel of antibodies (monoclonal antibodies Pab 1801, D07 and polyclonal antibody CM1). No p53 expression was observed in any acinar carcinomas independent of grade and stage. For non acinar carcinomas only small cell and transitional cell carcinomas exhibited detectable amounts of p53 protein in tumour cell nuclei. The prevalence of p53 overexpression in prostate carcinoma is relatively low compared with that found in many other tumours. In the present study, the overexpression of p53 in a small cell carcinoma and in a transitional cell carcinoma suggest that the loss of suppressing role of p53 gene may be an important mechanism in the genesis and in the development of these uncommon tumours.

Novel expression of gastrin (CCK-B) receptors in pancreatic carcinomas and dysplastic pancreas from transgenic mice

Transgenic mice bearing the elastase I promoter--SV40 T-antigen fusion gene (ELSV) develop pancreatic acinar cell carcinomas by 3 to 6 months of age. The purpose of the study was to determine if pancreatic carcinomas and dysplastic pancreas from the Tg (Ela-1, SV40E + Ela-1, neo) Bri19 strain of ELSV transgenic mice express gastrin (CCK-B) receptors. To accomplish this, we utilized iodine 125 (125I)-gastrin binding studies, reverse transcription-polymerase chain reaction (RT-PCR), and Southern blot analysis to examine pancreatic carcinomas from 26-week-old male ELSV transgenic mice, dysplastic pancreas from 8-week-old male ELSV transgenic mice, and normal pancreas from 30-week-old nontransgenic male mice (SJL/J) and from 8-week-old nontransgenic male mice (B6SJLF1/J). No saturable gastrin binding to normal nontransgenic mouse pancreas was found. In contrast, saturable gastrin binding was detected at pH 6.5, 22 degrees C, in 9 of 13 pancreatic carcinomas and all 5 dysplastic pancreata. Competitive inhibition 125I-gastrin binding assays showed gastrin bound to a single class of high-affinity receptors (receptor binding affinity [Kd] 0.11 +/- 0.02 nM, binding capacities ranging from 1 to 60 fmol/mg protein for pancreatic carcinomas; Kd: 0.15 +/- 0.04 nM, binding capacities ranging from 1 to 9 fmol/mg protein for dysplastic pancreas). RT-PCR and Southern blot analysis confirmed 125I-gastrin binding studies by demonstrating gastrin (CCK-B) receptor mRNA expression in pancreatic carcinomas and dysplastic pancreas but an absence of mRNA expression in normal nontransgenic mouse pancreas. In conclusion, pancreatic carcinomas and dysplastic pancreas in ELSV transgenic mice novelly express gastrin (CCK-B) receptors. This expression may provide a growth advantage to acinar cells as part of the multistage process of carcinogenesis.