Towards a More Standardized Approach to Pathologic Reporting of Pancreatoduodenectomy Specimens for Pancreatic Ductal Adenocarcinoma: Cross-continental and Cross-specialty Survey From the Pancreatobiliary Pathology Society Grossing Working Group

In recent literature and international meetings held, it has become clear that there are significant differences regarding the definition of what constitutes as margins and how best to document the pathologic findings in pancreatic ductal adenocarcinoma. To capture the current practice, Pancreatobiliary Pathology Society (PBPS) Grossing Working Group conducted an international multispecialty survey encompassing 25 statements, regarding pathologic examination and reporting of pancreatic ductal adenocarcinoma, particularly in pancreatoduodenectomy specimens. The survey results highlighted several discordances; however, consensus/high concordance was reached for the following: (1) the pancreatic neck margin should be entirely submitted en face, and if tumor on the slide, then it is considered equivalent to R1; (2) uncinate margin should be submitted entirely and perpendicularly sectioned, and tumor distance from the uncinate margin should be reported; (3) all other surfaces (including vascular groove, posterior surface, and anterior surface) should be examined and documented; (4) carcinoma involving separately submitted celiac axis specimen should be staged as pT4. Although no consensus was achieved regarding what constitutes R1 versus R0, most participants agreed that ink on tumor or at and within 1 mm to the tumor is equivalent to R1 only in areas designated as a margin, not surface. In conclusion, this survey raises the awareness of the discordances and serves as a starting point towards further standardization of the pancreatoduodenectomy grossing and reporting protocols.

Role of tumour location and surgical extent on prognosis in T2 gallbladder cancer: an international multicentre study

BACKGROUND

In gallbladder cancer, stage T2 is subdivided by tumour location into lesions on the peritoneal side (T2a) or hepatic side (T2b). For tumours on the peritoneal side (T2a), it has been suggested that liver resection may be omitted without compromising the prognosis. However, data to validate this argument are lacking. This study aimed to investigate the prognostic value of tumour location in T2 gallbladder cancer, and to clarify the adequate extent of surgical resection.

METHODS

Clinical data from patients who underwent surgery for gallbladder cancer were collected from 14 hospitals in Korea, Japan, Chile and the USA. Survival and risk factor analyses were conducted.

RESULTS

Data from 937 patients were available for evaluation. The overall 5-year disease-free survival rate was 70·6 per cent, 74·5 per cent for those with T2a and 65·5 per cent among those with T2b tumours (P = 0·028). Regarding liver resection, extended cholecystectomy was associated with a better 5-year disease-free survival rate than simple cholecystectomy (73·0 versus 61·5 per cent; P = 0·012). The 5-year disease-free survival rate was marginally better for extended than simple cholecystectomy in both T2a (76·5 versus 66·1 per cent; P = 0·094) and T2b (68·2 versus 56·2 per cent; P = 0·084) disease. Five-year disease-free survival rates were similar for extended cholecystectomies including liver wedge resection versus segment IVb/V segmentectomy (74·1 versus 71·5 per cent; P = 0·720). In multivariable analysis, independent risk factors for recurrence were presence of symptoms (hazard ratio (HR) 1·52; P = 0·002), R1 resection (HR 1·96; P = 0·004) and N1/N2 status (N1: HR 3·40, P < 0·001; N2: HR 9·56, P < 0·001). Among recurrences, 70·8 per cent were metastatic.

CONCLUSION

Tumour location was not an independent prognostic factor in T2 gallbladder cancer. Extended cholecystectomy was marginally superior to simple cholecystectomy. A radical operation should include liver resection and adequate node dissection.

Optimal surgical treatment in patients with T1b gallbladder cancer: An international multicenter study

BACKGROUND

There is no consensus on the optimal treatment of T1b gallbladder cancer (GBC) due to the lack of evidence and the difficulty of anatomy and pathological standardization.

METHODS

A total of 272 patients with T1b GBC who underwent surgical resection at 14 centers with specialized hepatobiliary-pancreatic surgeons and pathologists in Korea, Japan, Chile, and the United States were studied. Clinical outcomes including disease-specific survival (DSS) rates according to the types of surgery were analyzed.

RESULTS

After excluding patients, the 237 qualifying patients consisted of 90 men and 147 women. Simple cholecystectomy (SC) was performed in 116 patients (48.9%) and extended cholecystectomy (EC) in 121 patients (51.1%). The overall 5-year DSS was 94.6%, and it was similar between SC and EC patients (93.7% vs. 95.5%, P = 0.496). The 5-year DSS was similar between SC and EC patients in America (82.3% vs. 100.0%, P = 0.249) as well as in Asia (98.6% vs. 95.2%, P = 0.690). The 5-year DSS also did not differ according to lymph node metastasis (P = 0.688) or tumor location (P = 0.474).

CONCLUSIONS

SC showed similar clinical outcomes (including recurrence) and survival outcomes as EC; therefore, EC is not needed for the treatment of T1b GBC.

Histological complexities of pancreatic lesions from transgenic mouse models are consistent with biological and morphological heterogeneity of human pancreatic cancer

Although pancreatic cancer is the fourth leading cause of cancer death, it has received much less attention compared to other malignancies. There are several transgenic animal models available for studies of pancreatic carcinogenesis, but most of them do not recapitulate, histologically, human pancreatic cancer. Here we review some detailed molecular complexity of human pancreatic cancer and their reflection in histomorphological complexities of pancreatic lesions developed in various transgenic mouse models with a special concern for studying the effects of chemotherapeutic and chemopreventive agents. These studies usually require a large number of animals that are at the same age and gender and should be either homozygote or heterozygote but not a mixture of both. Only single-transgene models can meet these special requirements, but many currently available models require a mouse to simultaneously bear several transgene alleles. Thus it is imperative to identify new gene promoters or enhancers that are specific for the ductal cells of the pancreas and are highly active in vivo so as to establish new single-transgene models that yield pancreatic ductal adenocarcinomas for chemotherapeutic and chemopreventive studies.

Characterization of pancreatic lesions from MT-tgf alpha, Ela-myc and MT-tgf alpha/Ela-myc single and double transgenic mice

In order to identify good animal models for investigating therapeutic and preventive strategies for pancreatic cancer, we analyzed pancreatic lesions from several transgenic models and made a series of novel findings. Female MT-tgfα mice of the MT100 line developed pancreatic proliferation, acinar-ductal metaplasia, multilocular cystic neoplasms, ductal adenocarcinomas and prominent fibrosis, while the lesions in males were less severe. MT-tgfα-ES transgenic lines of both sexes developed slowly progressing lesions that were similar to what was seen in MT100 males. In both MT100 and MT-tgfα-ES lines, TGFα transgene was expressed mainly in proliferating ductal cells. Ela-myc transgenic mice with a mixed C57BL/6, SJL and FVB genetic background developed pancreatic tumors at 2–7 months of age, and half of the tumors were ductal adenocarcinomas, similar to what was reported originally by Sandgren et al [1]. However, in 20% of the mice, the tumors metastasized to the liver. MT100/Ela-myc and MT-tgfα-ES/Ela-myc double transgenic mice developed not only acinar carcinomas and mixed carcinomas as previously reported but also various ductal-originated lesions, including multilocular cystic neoplasms and ductal adenocarcinomas. The double transgenic tumors were more malignant and metastasized to the liver at a higher frequency (33%) compared with the Ela-myc tumors. Sequencing of the coding region of p16ink4, k-ras and Rb cDNA in small numbers of pancreatic tumors did not identify mutations. The short latency for tumor development, the variety of tumor morphology and the liver metastases seen in Ela-myc and MT-tgfα/Ela-myc mice make these animals good models for investigating new therapeutic and preventive strategies for pancreatic cancer.

Ductal neoplasia of the pancreas: nosologic, clinicopathologic, and biologic aspects

Most pancreatic neoplasia are of ductal lineage, characterized by tubule (gland), cyst, papilla, or mucin formation and expression of mucin-related glycoproteins and oncoproteins (eg, MUC1, CA19-9, CEA, DUPAN), as well as some subsets of cytokeratin (eg, CK19). Mutations of k-ras oncogene and DPC4 are also common in ductal neoplasia and generally not seen in nonductal tumors. A variety of pancreatic neoplasia fall under the heading of ductal neoplasia. Invasive ductal adenocarcinoma (DA) is the most important and constitutes the vast majority (>85%) of pancreatic tumors. DA is characterized by insidious infiltration and rapid dissemination, despite its relatively well-differentiated histologic appearance. In some variants of DA such as undifferentiated or sarcomatoid, evidence of ductal differentiation may be lacking or only focal. The presumed precursors of DA are microscopic intraductal proliferative changes that are now termed pancreatic intraepithelial neoplasia (PanIN). PanINs comprise a neoplastic transformation ranging from early mucinous change (PanIN-1A) to frank CIS (PanIN-3). A similar (in situ) neoplastic spectrum also characterizes intraductal papillary mucinous neoplasms and mucinous cystic neoplasms, which are cystic ductal-mucinous tumors with varying degrees of papilla formation, and may be associated with invasive carcinoma. As such, these can be regarded as mass-forming preinvasive neoplasia. Some intraductal papillary mucinous neoplasms are associated with invasive carcinoma of the colloid type. Colloid carcinoma of the pancreas appears to be a clinicopathologically distinct tumor with indolent behavior. Whereas most ductal pancreatic neoplasia are characterized by some degree of mucin formation, serous tumors, of which serous (microcystic) adenoma is the sole example, lack mucin formation, presumably because they recapitulate centroacinar ducts. They are typically benign tumors. It is recognized now that pancreatic carcinoma, like other malignant processes, is a genetic disease produced by progressive mutations in cancer-related genes. These alterations can be categorized as "early" such as k-ras mutation, HER-2/neu, PSCA, MUC5, and fascin overexpression; "intermediate" such as p16 inactivation, MUC1, and cyclin D1 overexpression; and finally as "late" such as p53 and DPC4 inactivation, BRCA2 mutation, and overexpression of ki-67, 14-3-3sigma, and mesothelin. Ductal neoplasia is the most important category among pancreatic tumors. It is important to appreciate the different types of ductal tumors because they vary greatly in their clinicopathologic characteristics and prognosis. Understanding the molecular mechanisms of ductal carcinogenesis will help develop more efficient prevention and therapy of these tumors.

Paraduodenal pancreatitis: a clinico-pathologically distinct entity unifying "cystic dystrophy of heterotopic pancreas", "para-duodenal wall cyst", and "groove pancreatitis"

A distinct form of chronic pancreatitis occurring predominantly in and around the duodenal wall (near the minor papilla) has been reported under various names, including cystic dystrophy of heterotopic pancreas, pancreatic hamartoma of duodenum, para-duodenal wall cyst, myoadenomatosis, and groove pancreatitis. Our experience with these lesions and the review of the literature show that these lesions have the following common characteristics: (1) The duodenal wall contains dilated ducts, some with inspissated secretions, and pseudocystic changes as well as adjacent stromal reactions including hypercellular granulation tissue, foreign-body type giant cell reaction engulfing mucoprotein material, and myofibroblastic proliferation. (2) Brunner's gland hyperplasia is typically present. (3) Dense myoid stromal proliferation, with intervening rounded lobules of pancreatic acinar tissue, creates a histologic picture reminiscent of "myoadenomatosis," "pancreatic hamartoma," or even leiomyoma in some cases. (4) Spillover of fibrosis into the adjacent pancreas and soft tissue occurs, especially in the "groove" area (between the pancreas, common bile duct and duodenum), including the region around the common bile duct. (5) Clinically, these lesions often mimic "pancreas cancer" or periampullary tumors, because of marked scarring as well as the ill-defined borders of the process. Patients with these findings are predominantly males, 40-50 years old, with a history of alcohol abuse. That the process is often centered in the region of minor papilla (and the adjacent pancreas) suggests that an anatomic variation of the ductal system may render this area particularly susceptible to the effects of alcoholic injury, and the myo-adenomatoid and cystic changes on the duodenal wall may in turn represent changes related to a localized recurrent pancreatitis. In conclusion, these clinicopathologic findings characterize a distinctive process that can be referred to as paraduodenal pancreatitis.

MUC1 and MUC2 in pancreatic neoplasia

MUCs are glycoproteins with various roles in homeostasis and carcinogenesis. Among other actions, MUC1 may inhibit cell-cell and cell-stroma interactions and function as a signal transducer, participating in cancer progression. In contrast, MUC2 is normally found only in goblet cells, where it contributes to the protective barrier function of these cells. Recently, a tumour suppressor role has been demonstrated for MUC2, and both MUC1 and MUC2 appear to have important roles in pancreatic neoplasia. MUC1 appears to be a marker of aggressive phenotype and may facilitate the vascular spread of carcinoma cells. In contrast, MUC2 is rarely detectable in aggressive pancreatic tumours, but is commonly expressed in intraductal papillary mucinous neoplasms (IPMNs), which are rare, indolent tumours, in intestinal IPMNs, and in indolent colloid carcinomas. MUC2 appears to be not only a marker of this indolent pathway, but also partly responsible for its less aggressive nature. Thus, in pancreatic neoplasia, MUC1 and MUC2 have potential diagnostic and prognostic value as markers of aggressive and indolent phenotypes, respectively, and have potential as therapeutic targets.

Sarcomatoid mesothelioma and its histological mimics: a comparative immunohistochemical study

AIMS

Differentiating sarcomatoid mesothelioma from other pleural-based spindle cell tumours by light microscopy can be challenging, especially in a biopsy. The role of immunohistochemistry in this differential diagnosis is not as well defined as it is for distinguishing epithelioid mesothelioma from adenocarcinoma. In this study, we investigate the utility of diagnostic immunohistochemistry for distinguishing sarcomatoid mesothelioma from its histological mimics, high-grade sarcoma and pulmonary sarcomatoid carcinoma.

METHODS

We stained 20 mesotheliomas with sarcomatoid components (10 biphasic and 10 sarcomatoid mesotheliomas) for pan-cytokeratin, cytokeratin 5/6, calretinin, WT-1, thrombomodulin, and smooth muscle actin. Intensity and distribution of staining were assessed using a semiquantitative scale. Only tumours with unequivocal staining were considered positive for tabulation. We compared the immunophenotypic profiles of these tumours with 24 high-grade sarcomas, 10 pulmonary sarcomatoid carcinomas, and 16 epithelioid mesotheliomas. The sarcomatoid carcinomas were also stained for thyroid transcription factor-1 (TTF-1).

RESULTS

Pan-cytokeratin stained 70% of sarcomatoid mesotheliomas, 17% of sarcomas, 90% of sarcomatoid carcinomas, and 100% of epithelioid mesotheliomas. Cytokeratin 5/6 and WT-1 stained most epithelioid mesotheliomas, but rarely stained sarcomas, sarcomatoid carcinomas, or the sarcomatoid components of mesothelioma. Calretinin and thrombomodulin each stained 70% of sarcomatoid mesotheliomas. However, calretinin was also positive in 17% of sarcomas and in 60% of sarcomatoid carcinomas, while thrombomodulin was positive in 38% of sarcomas and in 40% of sarcomatoid carcinomas. Smooth muscle actin was expressed in 60% of sarcomatoid mesotheliomas and in 58% of sarcomas, but in only 10% of sarcomatoid carcinomas. All 10 sarcomatoid carcinomas were negative for TTF-1.

CONCLUSIONS

Mesothelioma shows decreased expression of epithelial and mesothelial epitopes in its sarcomatoid components. A wide immunophenotypic overlap exists among sarcomatoid mesotheliomas, sarcoma, and sarcomatoid carcinomas. Cytokeratin and calretinin have the most value in differentiating sarcomatoid mesothelioma from sarcoma. However, because sarcomatoid mesothelioma can occasionally be cytokeratin-negative, the distinction between it and sarcoma may become arbitrary. With the exception of smooth muscle actin, all the markers studied showed similar distributions in sarcomatoid mesothelioma and sarcomatoid carcinoma, including frequent calretinin and thrombomodulin expression in both tumours. Thus, immunohistochemistry plays a more limited role in the differential diagnosis of sarcomatoid tumours compared with epithelioid tumours. For sarcomatoid tumours involving the pleural lining, clinicopathological data, especially information about the gross appearance of the tumour (i.e. localized versus diffuse pleural-based mass), should be noted and carefully correlated with microscopic and immunohistochemical findings.

Expression of ERRP in normal and neoplastic pancreata and its relationship to clinicopathologic parameters in pancreatic adenocarcinoma

INTRODUCTION AND AIMS

Epidermal growth factor (EGF) and its receptor (EGFR) play crucial roles in cellular signaling in many malignancies, including pancreatic neoplasia. Attenuation of EGFR signaling has been considered novel strategy for the management of human malignancies in several ongoing clinical trials. We recently isolated a novel negative regulator of EGFR, termed EGF receptor related protein (ERRP), whose expression appears to attenuate EGFR activation. In the current study, the expression of ERRP in normal and neoplastic pancreas was investigated and correlated with the clinicopathologic parameters in pancreatic ductal adenocarcinoma (DA).

METHODOLOGY

Using rabbit polyclonal antibody that specifically interacts with ERRP, immunohistochemical staining was performed on 45 benign pancreata and 106 cases of DA. The intensity and percentage of cells with cytoplasmic and membranous staining were scored as 0, 1, 2, or 3. A combined score was calculated as intensity x percent/3, and for comparative analysis, the data were arbitrarily divided into three groups: <20, 20-49, and > or =50. The expression of ERRP was correlated with patient age, gender, race, tumor size, stage, grade, and survival.

RESULTS

ERRP was expressed in most benign ductal epithelium and islet cells, but not in normal acinar cells. In pancreatic ductal adenocarcinoma, ERRP expression frequency decreased progressively from well (WD) to moderate (MD) to poorly differentiated (PD) carcinoma (58%, 43%, and 15% respectively, < 0.001). ERRP expression was correlated with survival in DA showing decreased median survival with decreased ERRP score ( = 0.0035). Median survival of the lower intensity (0 or 1) group was less than that of the higher intensity (2 or 3) group (8 14 months, = 0.002). The higher expressing group (> or =50% of cells) had longer median survival (17 months) than the lower expressing (<50% of cells) group (10 months, = 0.003). Stepwise multiple regression analyses revealed that ERRP expression score and tumor grade are the significant predictors of survival in pancreatic ductal carcinomas ( < 0.03).

CONCLUSION

ERRP is usually expressed in benign ductal epithelium, but not in ductal adenocarcinoma. Its expression decreases with decreasing tumor differentiation. Low levels of ERRP are associated with poor clinical outcome, suggesting that progressive loss of ERRP, a negative regulator of EGFR, may partly stimulate aggressive tumor cell growth in pancreatic adenocarcinoma.

Pancreatic cancer: the evolving role of systemic therapy

Pancreatic adenocarcinoma is the fourth leading cause of cancer mortality in the US. The outcome for patients with pancreatic cancer has not essentially altered over the past few decades. Several new drugs with activity against pancreatic cancer have recently been identified for use in palliative settings. Of these, gemcitabine is the most widely used agent against the disease, but its benefit is very modest. Pilot Phase II studies combining gemcitabine with 5-fluorouracil (5-FU), irinotecan, docetaxel or cisplatin show improved outcomes that need to be confirmed in randomised studies. Concurrent administration of gemcitabine and external beam radiation therapy (EBRT) for locally advanced pancreatic cancer is feasible and is currently undergoing efficacy evaluations. Current research in pancreatic cancer involves newer dosing schedules of gemcitabine, and combinations of gemcitabine with novel agents. Ultimately, better understanding of the molecular biology of pancreatic neoplasia will identify potential cellular targets for future development of new agents for pancreatic cancer.

Bryostatin 1 induces differentiation and potentiates the antitumor effect of Auristatin PE in a human pancreatic tumor (PANC-1) xenograft model

Pancreatic cancer has the worst prognosis of all cancers with a dismal 5-year survival rate. Hence, there is a tremendous need for development of new and effective therapy for this tumor. In an earlier study we reported a potent antitumor activity of Auristatin PE (AuriPE) against pancreatic tumor. In addition, we have also reported that bryostatin 1 (bryo1) induces differentiation of leukemia cells, but the effect of bryo1 has not been investigated in pancreatic tumors. This is the first report where we demonstrate that bryo1 induces differentiation and potentiates the antitumor effect of AuriPE in a human pancreatic tumor (PANC-1) xenograft model. A xenograft model was established by injecting the PANC-1 cells s.c. in severe combined immune deficient (SCID) mice. After development of the s.c. tumors, tumors were dissected and small fragments were transplanted in vivo to new SCID mice, with a success rate of 100% and a doubling time of 4.8 days. The SCID mouse xenograft model was used to test the in vivo differentiation effect of bryo1 and its efficacy when given alone or in combination with AuriPE. Sections from paraffin-embedded tumors excised from untreated (control) SCID mice revealed typical poorly differentiated adenocarcinoma of the pancreas. Interestingly, sections of s.c. tumors taken from bryo1-treated mice revealed carcinomas that were much lower grade and less aggressive, and displayed prominent squamous and glandular differentiation. In this study, the tumor growth inhibition (T/C), activity score and cure rate for bryo1, AuriPE and bryo1+AuriPE were 80%, (+) and 0/4; 0.0%, (++++) and 3/5; and 0.0%, (++++) and 3/4, respectively. Mice treated with either AuriPE or bryo1+AuriPE were free of tumors for more than 150 days and were considered cured. The use of bryo1 as a novel differentiating agent and its combination with AuriPE should be further explored for the treatment of adenocarcinoma of the pancreas.

Expression of inflammatory modulator COX-2 in pancreatic ductal adenocarcinoma and its relationship to pathologic and clinical parameters

Despite the exceedingly poor prognosis of pancreatic cancer, it is often histologically well to moderately differentiated. The apparent resistance to conventional therapeutic modalities is poorly understood and may be related to the molecules involved in its progression or its propensity for perineurial invasion. Cyclooxygenase-2 (COX-2) is an inducible enzyme homologous to COX-1 that is responsible for production of prostaglandins at sites of inflammation. It is activated by a variety of growth factors and tumor promoters, and it has been implicated in cancer progression. It may also have a role in the resistance to therapy. Anti-COX-2 agents have been documented to have antitumor activity, and some are now being tested in the therapy for various cancers, including those of the pancreas. Experience regarding the rate of COX-2 expression in pancreatic cancer and its relationship to the clinical and biologic parameters is very limited. In this study, immunohistochemical stains for COX-2 have been performed on 120 cases of pancreatic ductal adenocarcinoma. The stains were scored according to the percentage (0: no staining, 1: < 10%, 2: 10-50%, and 3: >50% of the cells staining) and intensity (0 for no staining, 1 for mild staining, and 2 for dark staining) of staining. Based on the combined score for each case, they were divided into low expressors (percentage and intensity < or =1) and high expressors (percentage or intensity >1). In addition to global scoring for each case, the glandular and solid (poorly differentiated) components, when present, were scored separately. The global scores were correlated with clinical and biologic parameters. Seventy-four percent of the cases exhibited expression of COX-2 and 53% were high expressors. No significant association was observed when comparing the global COX-2 expression to survival, tumor size, stage, and vascular invasion. Increased perineural invasion was found to be significantly associated with COX-2 expression (p < 0.05). Increased expression was also more common in the glandular component as compared with the solid component of the tumors (68% versus 35%, p < 0.05). Of the 34 patients who received radiotherapy, 9 were low expressor (median survival 19.5 months) and 25 were high expressors (median survival 14 months). The difference in survival was not statistically significant.

Pancreatic intraepithelial neoplasia: a new nomenclature and classification system for pancreatic duct lesions

Proliferative epithelial lesions in the smaller caliber pancreatic ducts and ductules have been the subject of numerous morphologic, clinical, and genetic studies; however, a standard nomenclature and diagnostic criteria for classifying these lesion have not been established. To evaluate the uniformity of existing systems for grading duct lesions in the pancreas, 35 microscopic slides with 35 representative duct lesions were sent to eight expert pathologists from the United States, Canada, and Europe. Kappa values for interobserver agreement could not be calculated initially because more than 70 different diagnostic terms were used by the eight pathologists. In several cases, the diagnoses rendered for a single duct lesion ranged from "hyperplasia," to "metaplasia," to "dysplasia," to "carcinoma in situ." This review therefore demonstrated the need for a standard nomenclature and classification system. Subsequently, during a working group meeting, the pathologists agreed to adopt a single standard system. The terminology pancreatic intraepithelial neoplasia (or PanIN) was selected, and diagnostic criteria for each grade of PanIN were established (http://pathology.jhu.edu/pancreas_panin). This new system was then evaluated by having the eight pathologists rereview the original 35 cases. Only seven different diagnoses were rendered, and kappa values of 0.43, 0.14, and 0.42 were obtained for PanINs 1, 2, and 3 respectively. Cases assigned other diagnoses (e.g., squamous metaplasia) collectively had a kappa value of 0.41. These results show both the potential of the classification system, and also the difficulty of classifying these lesions even with a consistent nomenclature. However, even when there is lack of consensus, having a restricted set of descriptions and terms allows a better understanding of the reasons for disagreement. It is suggested that we adopt and apply this system uniformly, with continued study of its reliability and use, and possibly further refinement. The acceptance of a standard classification system will facilitate the study of pancreatic duct lesions, and will lead ultimately to a better understanding of their biologic importance.

Colloid (mucinous noncystic) carcinoma of the pancreas

In the past, colloid (mucinous noncystic) carcinoma (CC) of the pancreas had been included under the category of ordinary ductal adenocarcinoma, a tumor with a dismal prognosis, or was frequently misdiagnosed as mucinous cystadenocarcinoma. The clinicopathologic features of CC have not yet been well characterized, because most cases on record have been parts of studies on either mucinous cystic neoplasms (MCN) or intraductal papillary mucinous neoplasms (IPMN), with which colloid carcinomas are frequently associated. To determine the clinicopathologic characteristics of CC, 17 pancreatic tumors composed predominantly (>80%) of CC (defined as nodular extracellular mucin lakes with scanty malignant epithelial cells) and in which the invasive carcinoma measured larger than 1 cm were studied. Ten of these were originally classified as mucinous ductal adenocarcinoma and four as mucinous cystadenocarcinoma. The mean age of the patients was 61 years; 9 were men and 8 were women. The mean size of the CC was 5.3 cm (range, 1.2-16 cm). In more than half of the patients, CC represented the invasive component of an IPMN (in nine cases) or MCN (in one case). The tumors were composed of well-defined pools of mucin with sparse malignant cells in various patterns of distribution. Signet-ring cells floating in the mucin (but not as individual cells infiltrating stroma, a characteristic finding of signet-ring cell adenocarcinomas) were commonly identified and were prominent in five cases. Perineurial invasion was noted in six cases and regional lymph node metastases in eight. Mutation in codon 12 of the k-ras gene was detected in only 4 of 12 cases studied and p53 mutation in 2 of 9. Immunohistochemical and histochemical mucin stains suggested luminalization of the basal aspects of the cells. Five-year survival was 57%. At an overall mean follow up of 57 months, 10 patients were alive with no evidence of disease (median, 79 mos), including four with lymph node metastasis, three others with perineurial invasion, and another with vascular invasion. Four patients died of disease (18, 18, 25, and 26 mos), and three died of thromboembolism (with persistent disease) at 2, 5, 10 months. All seven patients who died with or of tumor had undergone incisional biopsy of the tumor either before the operation or intraoperatively, whereas none of the patients who were alive had incisional biopsy. When compared with 82 cases of resectable ordinary ductal adenocarcinoma on whom follow-up and staging information was complete, it was found that the patients with CC present with larger tumors (p = 0.03) but lower stage (p = 0.01). The prognosis of CC is significantly better: 2-year and 5-year survival are 70% versus 28% and 57% versus 12%, respectively (p = 0.001). In conclusion, pancreatic CC may occur with or without an identifiable IPMN and MCN component, and should be distinguished from mucinous cystadenocarcinoma, ordinary ductal adenocarcinoma, and signet-ring cell adenocarcinoma. CC of the pancreas is associated with a significantly better prognosis than ordinary ductal adenocarcinoma. In addition to its distinctive morphologic and clinical characteristics, CC of the pancreas also appears to have a low incidence of mutation in codon 12 of the k-ras gene. In cases with a clinical suspicion of colloid carcinoma, the possibility that an incisional biopsy may contribute to thromboembolic complications or even dissemination of the tumor may need to be considered. The luminalization of the basal aspects of the tumor cells may be the cause of stromal mucin accumulation that characterizes colloid carcinoma and may act as a containing factor.

Magnetic resonance imaging to measure therapeutic response using an orthotopic model of human pancreatic cancer

Pancreatic cancer is one of the most incurable and lethal human cancers in the United States. To facilitate development of novel therapeutic agents, we previously established an orthotopic pancreatic tumor model that closely mimics the natural biological behavior of human pancreatic cancer. In this study, magnetic resonance imaging (MRI) techniques were developed to detect tumor formation noninvasively and monitor serially tumor growth kinetics in this orthotopic model used for experimental drug testing. By using an optimized T2-weighted imaging method, we were able to distinguish human pancreas cancer from normal mouse pancreas. Orthotopic tumor formation was detected as early as day 1 after tumor cell implantation with a tumor volume as small as 12 mm3. Mice with evidence of tumor were separated into four treatment groups: control, auristatin-PE, gemcitabine, and their combination. After treatment, the mice were imaged at least three times before termination of the experiment. Comparison between MRI tumor volume measurements and tumor weights made at biopsy resulted in a correlation coefficient of 0.98. The tumor growth curves constructed from serial magnetic resonance imaging (MRI) measurements clearly showed tumor growth inhibition in treated mice compared with the control group. As expected, the group treated with the combination had the highest response rate compared with either auristatin-PE or gemcitabine alone, and the data were statistically highly significant (p < 0.004). From these results, we conclude that noninvasive MRI can be used to monitor serially therapeutic response in this orthotopic human pancreatic tumor model and can be used in the future to evaluate novel antitumor agents before human studies.

Mixed epithelial and stromal tumor of the kidney

We describe the clinicopathologic features of 12 patients with a distinctive tumor of the kidney characterized by a mixture of epithelial and stromal elements that form solid and cystic growth patterns. Similar tumors were reported previously in the literature under various names, including adult mesoblastic nephroma. All but one of the patients were women. The only man had a long history of treatment with lupron and diethylstilbesterol. Seven of the women had histories of long-term oral estrogen use of whom six had undergone total abdominal hysterectomy and bilateral salpingo-oophorectomy several years prior, and the seventh patient had been using oral contraceptives for many years. Another woman had this operation but did not receive any hormone therapy. Ages ranged from 31 to 71 years (mean, 56 yrs). Six patients presented with symptoms, including pain and infections attributable to mass effect, and in six the tumor was detected incidentally. Grossly, the tumors were well-circumscribed (mean size, 6 cm; range, 3-12 cm) and consisted of solid and cystic components, most often in equal proportions but in variable distribution. Microscopically, the spindle cell component ranged in appearance from scar-like fibrous tissue to leiomyoma-like interlacing fascicles; usually there was a mixture of both. More cellular foci reminiscent of ovarian stroma or solitary fibrous tumor were also present. No blastema was present. Epithelial elements (composed of clusters of tubules with variable lining) were scattered amidst the spindle cells, and focally transformed into large cysts lined by cells with abundant pink cytoplasm and a hobnail appearance. Immature epithelial elements typical of Wilms' tumor were not present. Muscle markers (desmin and smooth muscle actin) were positive diffusely and strongly in the spindle cells of all tumors, whereas HMB-45 and CD34 were absent. Estrogen receptors were detected in the nuclei of spindle cells in seven tumors and progesterone receptors in three. The distinctive clinicopathologic characteristics of these lesions warrant their classification as a separate category of kidney tumor. We suggest the descriptive term "mixed epithelial and stromal tumor" for this group until its nature and relationship to other kidney lesions are further clarified. Its preponderance in females with a history of long-term estrogen replacement and the history of long-term sex-steroid use in the only male patient, combined with the frequent content of estrogen and progesterone receptors in the spindle cells, suggest that the hormonal milieu plays a role in the evolution of these tumors. The clinical and pathologic parallels with mucinous cystic tumors of pancreas and liver raise the possibility of a common pathogenetic mechanism that may be linked to the periductal fetal mesenchyme. We think this entity is a benign composite neoplasm in which stroma and epithelium are both integral neoplastic components.

Genetic, immunohistochemical, and clinical features of medullary carcinoma of the pancreas: A newly described and characterized entity

Medullary carcinomas of the pancreas are a recently described, histologically distinct subset of poorly differentiated adenocarcinomas that may have a unique pathogenesis and clinical course. To further evaluate these neoplasms, we studied genetic, pathological, and clinical features of 13 newly identified medullary carcinomas of the pancreas. Nine (69%) of these had wild-type K-ras genes, and one had microsatellite instability (MSI). This MSI medullary carcinoma, along with three previously reported MSI medullary carcinomas, were examined immunohistochemically for Mlh1 and Msh2 expression, and all four expressed Msh2 but did not express Mlh1. In contrast, all of the medullary carcinomas without MSI expressed both Msh2 and Mlh1. Remarkably, the MSI medullary carcinoma of the pancreas in the present series arose in a patient with a synchronous but histologically distinct cecal carcinoma that also had MSI and did not express Mlh1. The synchronous occurrence of two MSI carcinomas suggests an inherited basis for the development of these carcinomas. Indeed, the medullary phenotype, irrespective of MSI, was highly associated with a family history of cancer in first-degree relatives (P < 0.001). Finally, one medullary carcinoma with lymphoepithelioma-like features contained Epstein-Barr virus-encoded RNA-1 by in situ hybridization. Therefore, because of medullary carcinoma's special genetic, immunohistochemical, and clinical features, recognition of the medullary variant of pancreatic adenocarcinoma is important. Only by classifying medullary carcinoma as special subset of adenocarcinoma can we hope to further elucidate its unique pathogenesis.

Pancreatic tumors with cystic dilatation of the ducts: intraductal papillary mucinous neoplasms and intraductal oncocytic papillary neoplasms

Intraductal papillary mucinous neoplasms (IPMNs) and intraductal oncocytic papillary neoplasms (IOPNs) are the 2 types of intraductal neoplasms of the pancreas that may appear cystic because of dilatation of the ducts. Both are characterized by intraductal proliferation of mucinous cells usually arranged in papillary patterns. This proliferation is often associated with intraluminal mucin accumulation, which produces cystic dilatation of the ducts, mimicking mucinous cystic neoplasms. Endoscopic and radiologic studies and careful macroscopic examination are crucial for the correct diagnosis of IPMNs and IOPNs by showing the origin within the native ducts. Microscopically, these tumors display a spectrum of cytoarchitectural atypia that ranges from adenoma to borderline and to carcinoma-in-situ. Although they are defined as "intraductal tumors," IPMNs and IOPNs are associated with invasive carcinoma in about a third of the cases. It, therefore, appears that, like mucinous cystic neoplasms or pancreatic intraepithelial neoplasia involving the smaller ducts associated with ordinary ductal adenocarcinomas, these tumors are precursors of invasive carcinoma. Invasive carcinomas associated with IPMNs are of either tubular or colloid (mucinous noncystic) types, whereas those associated with IOPNs may be oncocytic. Even in the presence of invasive carcinoma, these tumors may follow a more protracted clinical course than ordinary ductal adenocarcinoma. On the other hand, rare examples of IPMNs after an aggressive clinical course despite the lack of any identifiable invasive carcinoma are on record. Therefore, IPMNs and IOPNs should be examined carefully and sampled extensively, first, to confirm that the main pathology is an intraductal process and, more importantly, to rule out the presence of an invasive carcinoma.

Cystic forms of typically solid pancreatic tumors

In addition to the well-known cystic lesions, the differential diagnosis of pancreatic cysts also includes cystic counterparts (or cystic change in) otherwise typically solid tumors of this organ. Pancreatic endocrine neoplasms (islet cell tumors) and ductal adenocarcinomas sometimes undergo cystic degeneration, the latter usually due to necrosis. Also, although acinar cell carcinoma is typically a solid tumor, its rare cystic counterpart, "acinar cell cystadenocarcinoma," has been reported. A rare variant of pancreatic ductal adenocarcinoma referred to as "large-duct-type" is characterized by microcystic ectasia of the invasive glands and may mimic other cystic tumors at the microscopic level. Secondary tumors, although exceedingly rare, may also potentially fall into the differential diagnosis of pancreatic cysts. Often, the morphological characteristics of these lesions are identical to those of their solid counterparts, and their diagnosis is not difficult if one is aware of their existence. This review focuses on these cystic counterparts of otherwise characteristically solid pancreatic neoplasms. Solid pseudopapillary tumor, in which cystic degeneration is so common that "cystic" has been a part of many alternate terms assigned to this neoplasm, is discussed in another article of this issue of Seminars in Diagnostic Pathology.

Squamous-lined cysts of the pancreas: lymphoepithelial cysts, dermoid cysts (teratomas), and accessory-splenic epidermoid cysts

In the pancreas, 3 types of morphologically similar lesions may present as "squamous cysts": Lymphoepithelial cysts, dermoid cysts (monodermal teratomas), and epidermoid cysts in intrapancreatic accessory spleen. Lymphoepithelial cysts (LECs) are seen predominantly in men (M/F: 4/1) and in adulthood (mean age, 56, and range, 35 to 74 years). They may occur at any site of the organ (head, body, or tail). LECs are well-delineated cysts that may be multilocular (60%) or unilocular (40%), and they are characterized microscopically by stratified squamous epithelium surrounded by a band of mature lymphoid tissue with intervening well-formed germinal centers. Solid lymphoepithelial clusters are seldom seen. The pathogenesis of LECs is unclear; clinical diseases that are known to be associated with their counterparts in the salivary glands such as Sjogren disease or human immunodeficiency virus have not been documented for the LECs of the pancreas. The second type of squamous-lined cyst in the pancreas is the epidermoid cyst arising in intrapancreatic accessory spleen. These are located almost exclusively in the tail of the pancreas, in the fourth decade of life (mean age = 38). Their mean size is 4.5 cm (range, 2.3 to 6.5). In some cases, the cyst lining may be partly mucinous. Dermoid cysts of the pancreas are also rare. The cases that appear to be true dermoid cysts occur in a younger age group (mean age, 23, range, 2 to 53 years), and in contrast with LEC, there is no gender predominance. Mucinous epithelium, respiratory-type mucosa and sebaceous units are more readily identifiable in dermoid cysts, and they may contain hair. Subepithelial lymphoid tissue is not a feature. They are sometimes complicated by suppurative infections. The importance of these lesions is in their distinction from other cystic neoplasms, especially mucinous cystic tumors.

High-grade extraskeletal myxoid chondrosarcoma: a high-grade epithelioid malignancy

AIMS

Extraskeletal myxoid chondrosarcoma is typically a low-to-intermediate grade sarcoma that is associated with a prolonged clinical course. High-grade forms are rare and not well characterized. In this series we report the clinicopathological, immunohistochemical and ultrastructural findings in four cases of high-grade extraskeletal myxoid chondrosarcoma.

METHODS AND RESULTS

The patients were three men and one woman (ages 34-73 years) with tumours located in the thigh (two cases), paraspinal soft tissue and perineum. Three patients had metastases, one at 12 weeks, one at 10 months, and one at presentation of recurrent tumour. In the latter case the original tumour was low grade and became high grade when it recurred 3.5 years later. All three patients died of disease. One patient was lost to follow-up. The most striking histological feature in all four tumours was the presence of numerous large epithelioid cells. These cells were arranged in cords within myxoid matrix and in sheets devoid of matrix. Two tumours had areas of conventional extraskeletal myxoid chondrosarcoma intermixed with the high-grade areas. One tumour showed transition to high-grade spindle cell sarcoma. One tumour had cells with rhabdoid features. Immunohistochemically, two tumours focally expressed S100 protein, and one focally expressed EMA. All were negative with cytokeratin, desmin, smooth muscle actin, HMB45, CD31 and CD34. Ultrastructural features in three cases were compatible with chondrosarcoma; one tumour had aggregates of microtubules within rough endoplasmic reticulum, a characteristic feature of this tumour.

CONCLUSIONS

High-grade extraskeletal myxoid chondrosaroma is a rare and aggressive soft tissue sarcoma, and should be included in the differential diagnosis of other epithelioid malignancies.

Spindle cell tumors associated with mycobacteria in lymph nodes of HIV-positive patients: 'Kaposi sarcoma with mycobacteria' and 'mycobacterial pseudotumor'

Patients infected with HIV often have unusual manifestations of common infections and neoplasms. One such example is "mycobacterial pseudotumor," an exuberant spindle cell lesion induced in lymph nodes by mycobacteria. Kaposi sarcoma also produces a spindle cell proliferation in lymph nodes of HIV-positive patients. These two entities must be differentiated from one another because of differences in treatment and prognosis. We report here, however, three cases of intranodal Kaposi sarcoma with simultaneous mycobacterial infection, the occurrence of which has not been clearly documented. For comparison, we also studied three cases of mycobacterial pseudotumor, of which 14 cases have been described to date. There was considerable histologic overlap between these two lesions. Acid-fast bacilli were present in all cases, predominantly in the more epithelioid histiocytes in the cases of Kaposi sarcoma, and in spindle and epithelioid cells in the cases of mycobacterial pseudotumor. The morphologic features that favored Kaposi sarcoma over mycobacterial pseudotumor were the prominent fascicular arrangement of spindle cells and slitlike spaces, the lack of granular, acidophilic cytoplasm, and the presence of mitoses. Immunohistochemistry was a reliable adjunct study in the differential diagnosis, as the spindle cells in mycobacterial pseudotumor were positive for S-100 protein and CD68 whereas those of Kaposi sarcoma were CD31- and CD34-positive but negative for S-100 protein and CD68. Awareness that Kaposi sarcoma may coexist with mycobacterial infection in the same biopsy specimen is important because these lesions may be misdiagnosed as mycobacterial pseudotumor. The clinical impact of distinguishing between Kaposi sarcoma with mycobacteria and mycobacterial pseudotumor is significant because the presence of Kaposi sarcoma alters treatment and prognosis.

Utility of fluorescence in situ hybridization in pancreatic ductal adenocarcinoma

Often the diagnosis of pancreas cancer needs to be established from limited cytology specimens or small biopsies. Most ductal adenocarcinomas are histologically well to moderately differentiated and mimicked closely by pancreatitis, and therefore the microscopic diagnosis can be difficult. In addition, there appears to be significant heterogeneity in the outcome of the patients with pancreatic cancer, which cannot be predicted accurately by current prognosticators such as the grade and stage of the tumor. Therefore, there is need for methods that can be used as adjuncts to routine diagnostic and prognostic parameters. This study was designed to test the utility of the fluorescent in situ hybridization (FISH) method in identifying the molecular alterations, particularly the ones that have been detected with relatively high frequency in pancreas cancer. Formalin-fixed and paraffin-embedded tissues of 10 cases were enumerated for chromosome 7, 8, 17, 18, and 20 copy numbers by using alpha-satellite probes, and for c-myc by using a gene-specific probe. The number of signals per nucleus (reflecting chromosomal copy number and status of c-myc amplification) were counted in more than two areas containing 50-500 cells. Because of tumor heterogeneity, monosomy (loss of one chromosome copy) was defined arbitrarily as one signal in >25% of nuclei. C-myc amplification was defined as more than two gene copies in >20% of the cells. The most frequent signal losses were found in chromosomes 8 (four of 10 cases) and chromosome 17 (four of 10), followed by 20 (three of 10) and 18 (two of 10). No loss of chromosome 7 was detected. In contrast, gains in chromosome copy number were identified in only one of 10 tumors, which showed gain of both chromosome 7 and 18. Amplification of c-myc gene was detected in two of 10 cases, but neither of the two had aneuploidy for chromosome 8, where the c-myc gene is located. In addition, loss in c-myc signal was observed in one case that also showed loss of chromosome 8 copy number. FISH can be used to detect chromosomal changes in pancreatic cancer; abundance of lytic enzymes in this organ is not an impediment for the applicability of this technique. Therefore it can potentially be used in the future as an adjunct to the conventional diagnostic and prognostic markers. This study confirms that loss of chromosomes, particularly chromosomes 17 and 18, which carry the p53 and DCC genes, are common in pancreas cancer. Chromosome 20 is also frequently lost. In addition, in this study, alterations of chromosome 8, which is seen commonly in prostatic adenocarcinoma but has not been previously documented in pancreatic cancer, also was detected in five of 10 tumors. Furthermore, amplification of the c-myc gene, which is located in chromosome 8, was found in the two of the remaining five cases. Further studies are needed to confirm this high incidence of chromosome 8 and c-myc alterations and their possible role in the pathogenesis of pancreatic adenocarcinoma.

Spontaneous uterine rupture with fatal hemoperitoneum due to placenta accreta percreta: a case report and review of the literature

Placenta accreta percreta is an unusual cause of hemoperitoneum. Less than 50 such cases have been reported in the English-language literature over the past 100 years. A 22-year-old pregnant multigravida woman who had spontaneous uterine rupture with exsanguination caused by this entity is described. She had abdominal pain and cardiovascular collapse and died without a premortem diagnosis.

Non-accidental pediatric pelvic fracture: a case report

Few reports have documented pelvic fracture as a result of child abuse. We present a case with radiologic findings and pathologic correlation. Although documented patterns of osseous injury have been extensively described, a thorough skeletal evaluation must include a frontal view of the pelvis as well.

Cancer as a marker of genetic medical disease: an unusual case of medullary carcinoma of the kidney

Medullary carcinoma is a recently recognized tumor of the kidney with distinctive microscopic features; the most notable are diffuse and glandular growth patterns, inflammatory infiltrates, and rhabdoid/plasmacytoid cells. It is a clinically aggressive tumor that occurs in relatively young patients. Moreover, this tumor shows a peculiar clinical association: it occurs in patients with sickle cell hemoglobinopathy. The case presented is that of a 37-year-old black woman with a history of bronchial asthma who died suddenly. Autopsy showed a 4-cm renal mass with extension to the inferior vena cava and metastases to the liver. Histologic evaluation showed the characteristic findings of medullary carcinoma of the kidney. This diagnosis prompted the investigation and subsequent detection of sickle cell trait in the deceased, alerting the family to the genetic nature of her illness. This case is the first report of this entity since the original described series of patients and shows the unique nature of this cancer as a marker of a genetic medical disease.

Metastatic adenocarcinoma involving a mesothelial/monocytic incidental cardiac excrescence (cardiac MICE)

Mesothelial/monocytic incidental cardiac excrescence (MICE) is a recently described, peculiar microscopic finding in the endocardium or pericardium. These lesions are characterized by a mixture of mesothelial cell clusters and histiocytes, aggregated by fibrin. They have been interpreted as reactive or even artifactual, and the importance of distinguishing these aggregations from metastatic carcinoma has been emphasized. We report a unique case of a MICE that was seeded by clusters of metastatic adenocarcinoma cells. The patient was a 38-year-old woman with no history of previous cardiac instrumentation who was found to have an adenocarcinoma of the right lung involving the hilus but apparently not invading the pericardium. At surgery, a small fragment of tissue was found floating in the pericardial cavity, and microscopic examination revealed a cluster of histiocytes, mesothelial cells and fibrin (components of usual, benign MICE) in which rare pleomorphic adenocarcinoma cells were scattered. Unlike the surrounding mesothelial cells and histiocytes, the pleomorphic cells stained for carcinoembryonic antigen, epithelial membrane antigen, and BerEP4 and focally produced intracellular mucin, confirming their malignant glandular nature. It is possible that the surrounding mesothelial cells, histiocytes, and fibrin were formed in response to invasion of the pericardial space by adenocarcinoma. This case indicates that not all lesions with the characteristic architecture of MICE can be dismissed as non-neoplastic without careful evaluation of both the cellular constituents and the clinical circumstances.

Intraductal oncocytic papillary neoplasms of the pancreas

We describe the clinical and pathologic features of 11 intraductal oncocytic papillary neoplasms of the pancreas, a hitherto unrecognized tumor. The patients were six men and five women, and most of the tumors were in the head (head: body/tail = 8:3). The mean patient age was 62 (range, 39-78), and the average tumor size was 6 cm. Grossly the tumors exhibited mucin-filled cysts containing nodular papillary projections. Dilated ducts communicating with the main tumor were sometimes noted. Microscopically the cystic structures appeared to represent dilated ducts containing intraductal tumor. The tumors were characterized by variably complex, arborizing papillary structures. The papillae had thin, delicate fibrovascular cores with focal myxoid changes and were lined by stratified oncocytic cells. Goblet cells and intra-epithelial mucin-containing lumina were present, the latter resulting in a characteristic cribriform pattern. The exuberance of the epithelial proliferation varied from case to case and between different regions within individual tumors; solid sheets of cells were often identified. Although the degree of cytologic atypia was not generally severe, the complexity of the architecture justified a designation of intraductal oncocytic papillary carcinoma in 10 of the 11 cases. In nine cases the tumor was entirely intraductal; one case exhibited focal microinvasion and another showed widespread invasive carcinoma, the invasive elements appearing cytologically similar to the intraductal papillary components. The oncocytic cells stained positively with phosphotungstic acid hematoxylin and Novelli stains. Immunohistochemically, all cases stained positively for B72.3, and five cases showed focal, weak luminal membrane staining for carcinoembryonic antigen. Ultrastructurally many of the cells were packed with mitochondria, and mucin was also identified. Seven patients were alive and free of tumor from 1 month to 3 years (average, 1 year) after resection. Two patients died postoperatively. The remaining two patients died with no evidence of disease at 2.5 and 5 years, the latter following a recurrence at 2.5 years. We conclude that intraductal oncocytic papillary neoplasm is a distinctive pancreatic tumor that is usually intraductal but may develop invasive carcinoma and should be treated with complete resection.

Disseminated pneumocystosis without pulmonary involvement during prophylactic aerosolized pentamidine therapy in a patient with the acquired immunodeficiency syndrome

Pneumocystosis, the most common opportunistic infection associated with the acquired immunodeficiency syndrome, is usually restricted to the lungs and results in severe bilateral pneumonia, which is fatal unless vigorously treated. Rare cases have been reported in which involvement of other organs or disseminated disease occurred in addition to the pulmonary lesions. Pentamidine, an efficient drug used intravenously for the treatment of pulmonary pneumocystosis, has also recently been used in aerosolized form for the prevention of Pneumocystis infection in patients with the acquired immunodeficiency syndrome. In the present case, widely disseminated, though symptomless, pneumocystosis developed in a human immunodeficiency virus-positive individual treated prophylactically with aerosolized pentamidine. Despite heavy multiorgan infection with Pneumocystis carinii, the lungs revealed no microorganisms or characteristic inflammatory lesions. This case indicates that aerosolized pentamidine, while efficient against the pulmonary infection, may not produce fungicidal blood levels sufficient for the prevention of disseminated pneumocystosis.