Thyroid sclerosing mucoepidermoid carcinoma with eosinophilia: a clinicopathologic and molecular analysis of a distinct entity

Sclerosing mucoepidermoid carcinoma with eosinophilia is a rare thyroid neoplasm of uncertain pathogenesis that resembles salivary gland mucoepidermoid carcinoma. This multi-institutional study characterizes the clinicopathologic and molecular features of this tumor by utilizing next-generation sequencing to assess common mutations and gene fusions involved in thyroid carcinogenesis as well as fluorescence in-situ hybridization for MAML2 translocations typical of salivary gland mucoepidermoid carcinoma. Nine cases (6 females and 3 males, mean age: 59 years, range 30-77 years) were identified. All cases were comprised of nests and strands of tumor cells with both squamous and mucinous differentiation embedded in a fibrohyaline stroma with an inflammatory infiltrate replete with eosinophils. All cases were p63 positive, thyroglobulin negative and showed variable expression of TTF-1. All nine cases were negative for MAML2 rearrangements. Five cases successfully tested by next-generation sequencing (ThyroSeq v.2 assay) were negative for mutations and translocations commonly involved in thyroid carcinogenesis. NTRK1 showed overexpression but no evidence of translocation. On follow-up, one patient died of persistent disease, whereas one of four remaining patients with available follow-up (mean: 7.3 years, range 4-11 years) demonstrated recurrence at 4 years. Thus, we show that sclerosing mucoepidermoid carcinoma with eosinophilia appears molecularly and morphologically distinct from follicular and C-cell-derived thyroid tumors as well as from salivary gland mucoepidermoid carcinoma. The overall and recurrence-free survival for these patients may be lower than for other well-differentiated thyroid cancers.

Gnathic and peripheral ameloblastomas lack human papillomavirus DNA

Human papillomavirus (HPV) has been associated with a variety of head and neck neoplasms, including squamous cell carcinomas and Schneiderian papillomas. Ameloblastomas can arise from either the gnathic bones or peripheral soft tissues. Peripheral sinonasal ameloblastomas share clinical features with Schneiderian papillomas. A small number of reports have described detection of HPV DNA within ameloblastomas. However, Most of these cases was reported in the 1990s, used the polymerase chain reaction technique, and only examined gnathic tumors. The current study was designed to determine whether low- or high-risk HPV DNA could be detected in gnathic or peripheral ameloblastomas using in situ hybridization. Twenty-nine examples of gnathic osseous and peripheral head and neck ameloblastomas were obtained from the authors' archives (University of Virginia and the Johns Hopkins Hospital). High-risk HPV DNA was not detected in any of the 29 tumors analyzed. Low-risk HPV DNA was identified in only 1 tumor, which was peripheral in origin, and from an immunocompromised patient. We believe that the HPV in this case represents a background "passenger" infection. This study demonstrates that HPV of either high- or low-risk subtypes is unlikely to play a role in the pathogenesis of sinonasal ameloblastomas.

Morphology in conjunction with immunohistochemistry is sufficient for the diagnosis of mammary analogue secretory carcinoma

The recently described mammary analogue secretory carcinoma (MASC) is a low-grade salivary gland malignancy that harbors the recurrent cytogenetic abnormality t(12;15) (p13;q25) ETV6-NTRK3. Confirmation of this is currently considered the gold standard for diagnosis. Some have postulated that morphology together with supporting immunohistochemistry is sufficient to diagnose MASC. In this study we retrospectively review a series of 19 MASCs diagnosed based on histology in conjunction with immunohistochemistry; subsequently we performed in situ hybridization using an ETV6 break-apart probe. Immunohistochemistry for S100 protein and mammaglobin as well as fluorescence in situ hybridization using the Vysis ETV6 Dual Color Break-Apart FISH Probe Kit were performed on all cases. The 19 cases were from 12 females and 7 males with ages ranging from 16 to 76 years (mean = 45 years). Sixteen cases were from the parotid gland, 1 case was from a periparotid lymph node and 2 cases were from the submandibular gland. All 19 cases demonstrated moderate to strong expression of S100 protein. Eighteen cases demonstrated strong, diffuse expression of mammaglobin, while one case had only rare tumor cells that strongly expressed mammaglobin. Eighteen of 19 cases (95 %) demonstrated the ETV6 rearrangement by fluorescence in situ hybridization. Given that morphology together with immunohistochemistry is highly correlated with the ETV6 gene rearrangement, we conclude that molecular confirmation is not required to diagnose MASC.

From slide sets to sound bites: teaching and learning pathology in the digital age

Educational evolution is particularly important in pathology, particularly cytopathology, due to the vast amounts of independent learning required to master this field. In this study, learning challenges faced by pathology residents were addressed through a variety of educational modalities including 24 short (∼10 minute) online tutorials (dubbed "Sound Bites") covering selected topics in cytopathology as well as other areas of anatomic and clinical pathology. Additionally, residents were provided with an annotated glass slide set covering pediatric pathology with an associated multiple choice self-assessment as well as multiheaded microscope slide review sessions. Use of these modalities was tracked and residents surveyed about their experiences using them. All 20 residents (100%) reported using Sound Bites either from work computers, home computers, or mobile devices. Residents reported that easy accessibility, brevity, and opportunities for self-assessment were important variables contributing to this use, and that Sound Bite use would make them more likely to benefit from in-person teaching through lectures and/or slide sessions. Within 12 months of the release of the first Sound Bite, individual Sound Bites were accessed a total of 1169 times (mean: 49 times per Sound Bite). In contrast, slide sets were only accessed about once a month and were only employed by 30% of residents (6 of 20) for independent study; only 20% (4 of 20) completed the accompanying multiple choice self-assessment. All residents attended multiheaded microscope slide review sessions. Whereas traditional educational methods remain valuable tools in pathology education, these data suggest that short, web-based tutorials represent a valuable adjuvant teaching tool.

Ewing's family of tumors of the sinonasal tract and maxillary bone

The Ewing's family of tumors (EFT) are malignant neoplasms affecting children and young adults. Most cases arise in the long bones or the pelvis. Primary EFT of head and neck is uncommon and primary sinonasal EFT is even rarer. Previous studies have not focused on the sinonasal region specifically, and the published literature on sinonasal EFT consists of sporadic case reports. Fourteen cases of sinonasal EFT were available and had H&Es for review and immunohistochemical stains for CD99, S100, keratins, synaptophysin and desmin. FISH or RT-PCR was performed for EWSR1 abnormalities on 8 cases. The 14 identified patients included 5 males and 9 females, ranging from 7-70 years of age (mean 32.4 years). Tumors involved nasal cavity (5), sinuses (5) or both (4). Five patients had dural, orbital or brain involvement. The majority involved bone radiologically and/or microscopically. All cases were composed of small cells with variable cytoplasmic clearing. Focal or prominent nesting was noted in most cases. All cases were positive for CD99. Keratins (AE1/3 and/or CAM5.2), S100 and synaptophysin were positive in 4, 3 and 5 cases, respectively. All cases were negative for desmin. The 8 cases tested by FISH or RT-PCR were positive for EWSR1 abnormalities. Follow-up in 8 patients ranged from 1-168 months (average 11.3 m) showing 1 death due to metastatic disease, 1 death due to local disease, 1 patient alive with metastases and 5 patients disease-free at last follow-up. Interestingly, however, an analysis of the literature suggests a better prognosis for sinonasal EFT than EFT overall.

Collagenous crystalloids in myoepithelial carcinoma: report of a case and review of the literature

Since the first report of "tyrosine crystals" in a parotid mixed tumor by Bullock in 1953, authors have described several types of crystalloids in association with mixed tumor and related neoplastic and nonneoplastic entities. The principal classes of these include tyrosine-rich crystalloids, collagenous crystalloids, and one class variously referred to as tyrosine-rich crystals, nontyrosine crystalloids, and amylase crystalloids. We report a myoepithelial carcinoma of minor salivary gland origin containing numerous collagenous crystalloids. To our knowledge, this represents the first report of collagenous crystalloids in a case of myoepithelial carcinoma. In addition, we searched our institution's files for cases of pure myoepithelial tumors. No crystalloids of any form were identified in 27 myoepitheliomas and 15 myoepithelial carcinomas. We review the literature on salivary-related crystalloids, and we propose the term oncocyte/cyst-associated crystalloids to encompass the aforementioned third class of crystalloid. Given distinct morphologic and histochemical properties and given relatively limited disease associations, we conclude that in the appropriate clinical context, the identification of these crystalloids can be diagnostically useful.

p63 Expression in olfactory neuroblastoma and other small cell tumors of the sinonasal tract

Olfactory neuroblastoma (ONB) is a rare neoplasm of the head and neck region that is included in the differential diagnosis of other sinonasal tract malignancies. We studied the usefulness of using p63 as an aid in the diagnosis of ONB and other tumors of the sinonasal region. The specimens were 14 ONBs; 4 nasopharyngeal carcinomas (NPCs), nonkeratinizing subtype; 2 NPCs, undifferentiated subtype; 10 sinonasal undifferentiated carcinomas (SNUCs); 7 malignant melanomas; and 2 extranodal natural killer (NK)/T-cell lymphomas. We observed p63 expression in 5 ONBs (36%), 4 nonkeratinizing NPCs (100%), 1 undifferentiated NPC (50%), 2 SNUCs (20%); 0 malignant melanomas (0%); and 1 extranodal NK/T-cell lymphoma (50%). While all cases of NPC with positive staining for p63 showed strong and diffuse immunoreactivity, the ONB, SNUC, and lymphoma cases with positive immunoreactivity showed only focal staining for p63. No p63 expression was observed in malignant melanoma. We think p63 is a useful marker to help distinguish nonkeratinizing or undifferentiated NPC subtypes from various sinonasal tract malignancies. In particular, p63 helps distinguish nonkeratinizing and undifferentiated NPC subtypes from SNUC.

Array comparative genomic hybridization analysis of olfactory neuroblastoma

Olfactory neuroblastoma is an unusual neuroectodermal malignancy, which is thought to arise at the olfactory membrane of the sinonasal tract. Due to its rarity, little is understood regarding its molecular and cytogenetic abnormalities. The aim of the current study is to identify specific DNA copy number changes in olfactory neuroblastoma. Thirteen dissected tissue samples were analyzed using array comparative genomic hybridization. Our results show that gene copy number profiles of olfactory neuroblastoma samples are complex. The most frequent changes included gains at 7q11.22-q21.11, 9p13.3, 13q, 20p/q, and Xp/q, and losses at 2q31.1, 2q33.3, 2q37.1, 6q16.3, 6q21.33, 6q22.1, 22q11.23, 22q12.1, and Xp/q. Gains were more frequent than losses, and high-stage tumors showed more alterations than low-stage olfactory neuroblastoma. Frequent changes in high-stage tumors were gains at 13q14.2-q14.3, 13q31.1, and 20q11.21-q11.23, and loss of Xp21.1 (in 66% of cases). Gains at 5q35, 13q, and 20q, and losses at 2q31.1, 2q33.3, and 6q16-q22, were present in 50% of cases. The identified regions of gene copy number change have been implicated in a variety of tumors, especially carcinomas. In addition, our results indicate that gains in 20q and 13q may be important in the progression of this cancer, and that these regions possibly harbor genes with functional relevance in olfactory neuroblastoma.

The cytologic features of sinonasal undifferentiated carcinoma and olfactory neuroblastoma

Sinonasal undifferentiated carcinoma (SNUC) is a rare, aggressive malignancy of the sinonasal tract. Olfactory neuroblastoma (ONB) is an uncommon neuroectodermal tumor of the superior nasal cavity. Upon examining these lesions, a broad differential diagnosis of poorly differentiated round cell tumors must be considered. The cytologic features of SNUC and ONB have been rarely reported. We searched our cytology files for cases of SNUC and ONB and assessed the following: cellularity, architecture, cytoplasm, cell size, nuclear contours, nucleoli, chromatin, anisonucleosis/anisocytosis, mitotic activity, background, and nuclear crush. Seven cases of SNUC produced hypercellular smears with a single-cell-predominant pattern. Cells were intermediate-sized with irregular nuclear contours and small nucleoli. Nuclear crush and mitotic figures were noted. The background exhibited naked nuclei and karyorrhectic debris. Of 7 cases, 6 (86%) exhibited vacuoles or extracellular lumina. The 10 cases of ONB exhibited cellularity, cellular arrangement, and chromatin similar to SNUC. In contrast, ONBs demonstrated fibrillary cytoplasm and smooth nuclear contours; mitotic figures were generally absent. Homer Wright rosettes were encountered in 9 cases (90%). We believe that in the appropriate clinical context, a specific cytologic diagnosis should be possible.

alpha-methylacyl coenzyme A racemase is immunoreactive in extramammary Paget disease

alpha-Methylacyl-coenzyme A racemase (AMACR) has become a common tool in the diagnosis of morphologically difficult prostatic carcinoma and often is used in combination with the basal cell markers p63 and 34betaE12. Outside this context, applications have been limited. Although initially considered a specific marker of prostatic carcinoma, immunoreactivity for AMACR has been found in a variety of other neoplasms. We report findings in 21 cases of extramammary Paget disease (EMPD), a neoplasm not previously reported to show AMACR immunoreactivity. We found immunoreactivity for AMACR in 15 (71%) of 21 EMPD cases overall, in 5 (56%) of 9 cases in women, and in 10 (83%) of 12 cases in men. AMACR immunoreactivity is a common finding in EMPD in men and women.

Atypical small acinar proliferation: biopsy artefact or distinct pathological entity?

OBJECTIVE

To determine if atypical small acinar proliferation (ASAP) represents minimally sampled prostate cancer not fully evaluated on a biopsy or a distinct pathological entity, by examining prostates removed at radical cystectomy, as a finding of ASAP of the prostate on needle-core biopsy is closely associated with the detection of cancer on subsequent biopsy.

PATIENTS AND METHODS

In all, 65 consecutive cystoprostatectomy specimens taken from June 1990 to March 2004 had prostatic material reviewed by one genitourinary pathologist (S.E.M.). The presence of high-grade prostatic intraepithelial neoplasia (HGPIN), ASAP, and adenocarcinoma was recorded. Foci of ASAP found in the absence of cancer were assessed with additional sectioning, high-molecular weight keratin (CK903), and alpha-methylacyl coenzyme A racemase (AMACR) immunohistochemistry.

RESULTS

In all, 24 of 65 specimens (37%) had adenocarcinoma. Of the 41 without cancer, 18 (44%) had neither HGPIN nor ASAP, 14 (34%) had HGPIN alone, three (7%) had ASAP alone (four foci), and six had both HGPIN and ASAP (15%). Two foci of ASAP were not present on any further sectioning. The remaining eight foci all lacked CK903 stain, indicating disruption of the basal cell layer. Of these eight, only five were present for the AMACR stain, all of which were positive. Two of these five developed into a lesion considered cancer on further sectioning.

CONCLUSION

ASAP identified in incidental prostates represented marginally sampled cancer in at least two of 10 foci assessed. The remainder could not be resolved as benign on further evaluation, and remained suspicious for malignancy.

The mismatch repair protein status of colorectal small cell neuroendocrine carcinomas

Small cell neuroendocrine carcinoma (SCNC) of the colorectum is a rare and highly aggressive malignancy. It can be associated with conventional-type adenocarcinoma, and an overlying adenoma can often be identified. A disproportionate number has been noted to arise in the right colon. Although some phenotypes (eg, mucinous adenocarcinoma) have been shown to be associated with deficient mismatch repair (MMR) and thus microsatellite instability (MSI), the MMR protein status of colorectal SCNCs has not been investigated. This study investigated the status of 3 MMR proteins, hMLH1, hMSH2, and hMSH6, in SCNCs of the colorectum. Fifteen SCNCs were identified on the basis of previous descriptions and the World Health Organization histologic criteria for the diagnosis of pulmonary small cell carcinoma and immunohistochemical evidence of epithelial and neuroendocrine differentiation. Patient age and sex and tumor size and location were recorded. Immunohistochemistry was performed with antibodies to pancytokeratin (cocktail), CD56, neuron specific enolase, synaptophysin, chromogranin, hMLH1, hMSH2, and hMSH6. Patients' ages ranged from 44 to 87 years (mean age = 73 y) and there were 9 men and 6 women. Tumors were located in the right colon (6), sigmoid colon (4), and rectum (3) (the locations of 2 cases were not recorded) and ranged in size from 0.4 to 15 cm in greatest dimension (mean = 6.6 cm). All tumors showed immunoreactivity with antibodies to pancytokeratin and with antibodies to at least 1 neuroendocrine antigen. MMR proteins were intact by immunohistochemistry in all but a single case that had neither an identifiable precursor lesion nor positive internal control (hMLH1 loss). Colorectal SCNCs are rare and are often right-sided. They are aggressive and tend to occur in older individuals. Most colorectal SCNCs have intact MMR proteins, suggesting that they develop secondary to chromosomal instability rather than MSI. Our single case showing potential MMR protein loss suggests that this phenotype may be independent of the developmental pathway (ie, chromosomal instability vs. MSI). This may explain the rare cases of SCNC that have been identified in patients with hereditary nonpolyposis colon cancer.

Case-Matched comparison of contemporary radiation therapy to surgery in patients with locally advanced prostate cancer

PURPOSE

Few studies critically compare current radiotherapy techniques to surgery for patients with locally advanced prostate cancer, despite an urgent need to determine which approach offers superior cancer control. Our objective was to compare rates of biochemical relapse-free survival (BFS) and surrogates of disease specific survival among men with high risk adenocarcinoma of the prostate as a function of treatment modality.

METHODS AND MATERIALS

Retrospective data from 409 men with prostate-specific antigen (PSA) > or =10 or Gleason 7-10 or Stage > or =T2b cancer treated uniformly at one university between March 1988 and December 2000 were analyzed. Patients had undergone radical prostatectomy (RP), brachytherapy implant alone (BTM), or external beam radiotherapy with brachytherapy boost with short-term neoadjuvant and adjuvant androgen deprivation therapy (BTC). From the total study population a 1:1 matched-cohort analysis (208 patients matched via prostate-specific antigen, Gleason score) comparing RP with BTC was performed as well.

RESULTS

Estimated 4-year BFS rates were superior for patients treated with BTC (BTC 72%, BTM 25%, RP 53%; p < 0.001). Matched analysis of BTC vs. RP confirmed these results (BTC 73%, BTM 55%; p = 0.010). Relative risk (RR) of biochemical relapse for BTM and BTC compared with RP were 2.92 (1.95-4.36) and 0.56 (0.36-0.87), (p < 0.001, p = 0.010). RR for BTC from the matched cohort analysis was 0.44 (0.26-0.74; p = 0.002).

CONCLUSIONS

High-risk prostate cancer patients receiving multimodality radiation therapy (BTC) display apparently superior BFS compared with those receiving surgery (RP) or brachytherapy alone (BTM).

Hyalinizing Trabecular Adenoma of the Thyroid Revisited: A Histologic and Immunohistochemical Study of Thyroid Lesions With Prominent Trabecular Architecture and Sclerosis

BACKGROUND

Since its description, hyalinizing trabecular adenoma (HTA) of the thyroid has been a controversial entity. Some have considered it a unique entity, some have considered it a variant of papillary carcinoma (PC), and still others have considered it a nonspecific pattern that may be seen with a variety of thyroid lesions. Complicating the matter, studies demonstrating metastases have shown entities that do not appear to be HTAs as originally described, and molecular studies showing changes of PC have used methods that are not specific. This study reviews our experience with thyroid lesions that showed at least some histologic features of HTA and presents the immunohistochemical findings for these lesions using antibodies employed for the diagnosis of PC.

DESIGN

Our files were reviewed for all thyroid resection reports describing lesions with hyalinized or sclerotic stroma and a trabecular architecture within the diagnosis or diagnostic comment. All cases were reviewed and classified as either HTA or as different lesions based upon histologic features. Immunohistochemistry with antibodies to HBME1, CK19 and p63 was performed with all lesions and with a series of controls.

RESULTS

Eighteen thyroid lesions with prominent sclerosis or hyalinization and trabecular architecture were identified. Only 4 of these were found to completely match the histologic and cytologic descriptions of HTA by HE review. The other cases showed histologic features more compatible with other diagnoses including cellular adenomatoid nodule (5), follicular adenoma (4), follicular variant of PC (FVPC) (3), and epithelial neoplasm with features of FVPC (2). All HTAs lacked immunoreactivity for HBME1, CK19 and p63. All cases deemed to be adenomatoid nodules, follicular adenomas and epithelial neoplasms showed no immunoreactivity for HBME1 and CK19 and, of these, only a single AN showed immunoreactivity for p63. Cases deemed to be FVPCs showed diffuse immunoreactivity for HBME1 and CK19 and 1 reacted with antibodies to p63. Of control PCs and other thyroid lesions, reactivity for HBME1, CK19, and p63 was observed in 8/8, 7/7, and 7/8 and 3/27, 7/27, and 7/27 cases, respectively.

CONCLUSIONS

A sclerotic or hyalinized stroma with a trabecular growth pattern may be seen in a number of different thyroid lesions and, when seen, is usually a focal feature of a lesion other than HTA. Immunohistochemistry may be of assistance as cases of FVPC with prominent hyalinization and trabeculation will show immunoreactivity for HBME1 and CK19, whereas HTAs and other thyroid lesions with hyalinization and trabeculation will not.

Anorectal malignant melanoma: morphologic and immunohistochemical features

We reviewed 17 cases of primary anorectal malignant melanoma. Morphologic features evaluated included junctional change, pigmentation, morphology, and mitotic rate. Immunohistochemical stains were performed for/with S-100 protein, HMB-45, MelanA, tyrosinase, vimentin, KIT, and pankeratin. Morphologic subtypes were as follows: epithelioid, 12 cases; spindle cell, 7 cases; lymphoma-like, 10 cases; and pleomorphic, 6 cases. Pigmentation was present in 9 cases. Junctional change was present in 6 cases. The mitotic rate was 3 or more per high-power field in 8 cases. S-100 protein was present in all cases, HMB-45 stained 16 of 17, MelanA was present in 14 of 15, tyrosinase in 12 of 14, vimentin in 13 of 14, and KIT in 12 of 16. Pankeratin was absent in all cases. The mean length of follow-up was 25.6 months (range, 8-96 months), and the average survival with disease was 32.3 months (range, 8-96). No morphologic or immunohistochemical features were predictive of survival. Anorectal malignant melanoma shows considerable morphologic variability. Immunohistochemical staining is similar to cutaneous melanomas. Expression of KIT was present frequently, including cases with spindle cell morphologic features, in which it may lead to confusion with gastrointestinal stromal tumors.

"Undifferentiated" small round cell tumors of the sinonasal tract: differential diagnosis update

Sinonasal tract neoplasms composed of light microscopically seemingly "undifferentiated" small round cells often generate considerable diagnostic difficulty. Although the careful review of H&E-stained sections remains of critical and central importance in this evaluation, the recent improvements in the immunohistochemical diagnostic armamentarium and molecular diagnostic techniques applicable to paraffin-embedded tissue samples may add diagnostically valuable information. Accordingly, this review will discuss the differential diagnosis of undifferentiated small blue cell tumors of the sinonasal tract based on the light microscopic and clinical features and, as needed, the results of these ancillary studies. Tumors discussed include olfactory neuroblastoma, sinonasal undifferentiated carcinoma, small cell undifferentiated (neuroendocrine) carcinoma, undifferentiated (lymphoepithelioma-like) carcinoma, malignant melanoma, pituitary adenoma, Ewing sarcoma/peripheral neuroectodermal tumor, rhabdomyosarcoma, mesenchymal chondrosarcoma, small cell osteosarcoma, synovial sarcoma, extranodal natural killer/T-cell lymphoma, nasal type, and extramedullary plasmacytoma.

Squamous cell carcinoma variants of the upper aerodigestive tract

Squamous cell carcinoma (SCC) is by far the most common malignancy of the upper aerodigestive tract. Most conventional-type SCCs do not present the surgical pathologist with diagnostic difficulty. Certain variants, however, can histologically mimic benign and other malignant diseases. In such cases, correct diagnosis is important for prognostic and therapeutic reasons. This article discusses the clinicopathologic features of the upper aerodigestive tract variants of SCC, including verrucous carcinoma, papillary squamous cell carcinoma, basaloid squamous cell carcinoma, spindle cell carcinoma, adenosquamous carcinoma, adenoid squamous cell carcinoma, and undifferentiated carcinoma. It also discusses the differential diagnoses that must be considered and the use of ancillary testing, especially immunohistochemical analysis, for determining the correct diagnosis.

KIT and RCC Are Useful in Distinguishing Chromophobe Renal Cell Carcinoma From the Granular Variant of Clear Cell Renal Cell Carcinoma

The distinction between chromophobe renal cell carcinoma, the granular cell variant of clear cell renal cell carcinoma, and renal oncocytoma is a common diagnostic dilemma. The usefulness of KIT, CD10, RCC, and RON in the differential diagnosis of these renal epithelial tumors was investigated. KIT was 100% positive in chromophobe renal cell carcinoma (11 of 11) and renal oncocytoma (12 of 12). The KIT staining pattern was identical in both tumor types, with cytoplasmic membrane attenuation, and fine granular cytoplasmic staining. In contrast, KIT was absent in all granular cell variants of clear cell renal cell carcinoma (0 of 6). RCC was observed in more than 80% of the granular cell variant of clear cell renal cell carcinoma (5 of 6) but was negative in all chromophobe renal cell carcinomas (0 of 11) and renal oncocytomas (0 of 12). CD10 was expressed in 100% of the granular cell variant of clear cell renal cell carcinoma (6 of 6), 72% of chromophobe renal cell carcinomas (8 of 11), and 58% of renal oncocytomas (7 of 12). RON was 100% positive in the chromophobe renal cell carcinomas (11 of 11) and renal oncocytomas (12 of 12) but only 50% positive in the granular cell variant of clear cell renal cell carcinoma (3 of 6). Colloidal iron was diffusely and strongly positive in more than 80% of the chromophobe renal cell carcinomas (9 of 11), focally and weakly positive in 41% of the renal oncocytomas (5 of 12) but negative in all granular cell variant of clear cell renal cell carcinoma (0 of 6). The above results demonstrate that: 1) KIT is a very sensitive marker for both chromophobe renal cell carcinoma and renal oncocytoma; 2) immunohistochemistry using antibodies to KIT combined with RCC was sufficient to discriminate between chromophobe renal cell carcinoma and the granular cell variant of clear cell renal cell carcinoma; and 3) neither RON, nor KIT, nor a combination of this panel can be used to distinguish chromophobe renal cell carcinoma from renal oncocytoma. Colloidal iron staining aided in this distinction for the majority of the chromophobe renal cell carcinomas (more than 80% positive) and renal oncocytomas (close to 60% negative).

Evidence-based principles and practices in pathology: selected problem areas

Contrary to the intuitive impression of most pathologists, there are still many areas in laboratory medicine where evidence-based medicine (EBM) principles are not applied. These include aspects of both anatomic and clinical pathology. Some non-EBM practices are perpetuated by clinical "consumers" of laboratory services, because of inadequate education, habit, or over-reliance on empirical factors. Other faulty procedures are pathologist-driven, with similar underpinnings. This overview considers several exemplary problem areas representing non-EBM practices in the hospital laboratory. Such examples include ideas and techniques centering on metastatic malignancies, "targeted" oncological therapy, analysis of surgical margins in the excision of neoplasms, general laboratory testing and data utilization, evaluation of selected coagulation defects, administration of blood products, and analysis of hepatic iron-overload syndromes. The concepts illustrating departures from EBM are discussed for each of those topics.

Sporadic medullary carcinoma of the colon: a clinicopathologic comparison with nonhereditary poorly differentiated enteric-type adenocarcinoma and neuroendocrine colorectal carcinoma

We studied 68 sporadic colorectal carcinomas (CRCs) with medullary features (MCRCs) and compared them with 35 poorly differentiated purely "enteric" CRCs (ECRCs) and 15 purely neuroendocrine carcinomas (NECs) of grades II and III, all in patients lacking a family history of CRC. Potential clinicopathologic differences between the study groups were assessed. MCRCs were significantly more common in the ascending colon than were ECRCs, but there was no significant dissimilarity to NECs. ECRCs occurred more often in the rectosigmoid than MCRCs or NECs. MCRCs arose in older patients, and a marked sex difference also was noted. Despite an infiltrative growth pattern, MCRC was less likely than ECRC to manifest with stage III or IV disease, but there was no stage-related difference from NECs. Although the histologic images of MCRCs were evocative of neuroendocrine differentiation, chromogranin positivity and synaptophysin reactivity in that group did not differ meaningfully from that of ECRCs but was dissimilar to the 100% labeling of NECs. p53 immunolabeling was similar in the 3 tumor groups. Follow-up data in the study cases showed that 5-year mortality was 40% (27/68) for MCRC, 59% (19/32) for ECRC, and 93% (14/15) for NEC. Medullary CRC seems to be a distinct clinicopathologic variant of CRC, which does not have a neuroendocrine lineage. The biologic behavior of MCRC was better than that of ECRC or NEC.

Immunophenotypic Differences Between Intestinal-type and Low-grade Papillary Sinonasal Adenocarcinomas

Nonsalivary sinonasal adenocarcinomas can be divided into low-grade and high-grade tumors. The former are often papillary and the latter are usually of intestinal type, morphologically similar to metastatic colonic carcinoma. Antibodies to CDX2, a transcription factor gene highly specific for intestinal adenocarcinomas, MUC2, a mucin gene expressed in adenocarcinomas from various sites, and cytokeratins (CK) 7 and 20 were used to examine the two groups of tumors. Formalin-fixed, paraffin-embedded tissue from 22 sinonasal adenocarcinomas was reclassified into 9 high-grade intestinal-type, 3 high-grade nonintestinal, and 10 low-grade, predominantly papillary adenocarcinomas. Immunohistochemical staining was graded on a 0 to 4+ scale with 5% or greater tumor cell staining considered positive. Of the high-grade intestinal group, 78% demonstrated 4+ CDX2 positivity, with 44% MUC2 positive. Although 89% of this group was CK7 positive, the percent of staining was variable. A majority (67%) of the intestinal cases was 4+ CK20 positive. Almost every nonintestinal adenocarcinoma (90%) (low- and high-grade) was CK7 positive (7 of 9, 4+), without expression of any of the three colonic adenocarcinoma markers. The three high-grade nonintestinal tumors had the expression profile of the low-grade papillary group with the exception of focal MUC2 positivity in 1 case. Intestinal-type adenocarcinomas have an expression profile distinct from nonintestinal sinonasal adenocarcinomas. The former are similar, but not identical, to colonic adenocarcinomas. Immunohistochemical staining for CDX2, MUC2, and differential cytokeratins does not differentiate metastatic colorectal from primary sinonasal intestinal-type adenocarcinoma.

Bladder epithelium is abnormal in patients with neurogenic bladder due to myelomeningocele

OBJECTIVE

To describe the urothelium of the neurogenic bladder in patients with myelomeningocele on clean intermittent catheterization.

SETTING

Outpatient practice.

METHODS

Samples of bladder wall obtained from two groups of patients were examined for urothelium. The first group included 12 children and young adults with myelomeningocele and neurogenic bladder on intermittent catheterization for bladder emptying. The second group included eight children with vesicoureteral reflux and non-neurogenic bladder. Nine patients from the first group and four patients from the second group had urothelium. A contiguous section of each of the 13 samples with urothelium was stained for uroplakin expression, a marker of superficial bladder urothelium by immunohistochemistry.

RESULTS

Samples from children with reflux revealed normal bladder epithelium and a uniform layer of umbrella cells (95% CI: 0-60%). In contrast, the epithelium from all patients with myelomeningocele was abnormal (95% CI: 66-100%). Epithelium from five patients (four children, one adult) revealed chronic inflammation. Three patients (two children, one adult) had squamous metaplasia. The apical surface of the epithelium in all patients with chronic inflammation had some reactivity with anti-uroplakin antibody, but the cells staining positive for uroplakin were scattered along the lumenal surface of the epithelium. The apical surface of patients with squamous metaplasia was negative for uroplakin.

CONCLUSION

The urothelium of the neurogenic bladder in young patients with myelomeningocele is abnormal, with loss of uroplakin expression and altered urothelial proliferation.

Most osteomalacia-associated mesenchymal tumors are a single histopathologic entity: an analysis of 32 cases and a comprehensive review of the literature

Oncogenic osteomalacia (OO) is a rare paraneoplastic syndrome of osteomalacia due to phosphate wasting. The phosphaturic mesenchymal tumor (mixed connective tissue variant) (PMTMCT) is an extremely rare, distinctive tumor that is frequently associated with OO. Despite its association with OO, many PMTMCTs go unrecognized because they are erroneously diagnosed as other mesenchymal tumors. Expression of fibroblast growth factor-23 (FGF-23), a recently described protein putatively implicated in renal tubular phosphate loss, has been shown in a small number of mesenchymal tumors with known OO. The clinicopathological features of 32 mesenchymal tumors either with known OO (29) or with features suggestive of PMTMCT (3) were studied. Immunohistochemistry for cytokeratin, S-100, actin, desmin, CD34, and FGF-23 was performed. The patients (13 male, 19 female) ranged from 9 to 80 years in age (median 53 years). A long history of OO was common. The cases had been originally diagnosed as PMTMCT (15), hemangiopericytoma (HPC) (3), osteosarcoma (3), giant cell tumor (2), and other (9). The tumors occurred in a variety of soft tissue (21) and bone sites (11) and ranged from 1.7 to 14 cm. Twenty-four cases were classic PMTMCT with low cellularity, myxoid change, bland spindled cells, distinctive "grungy" calcified matrix, fat, HPC-like vessels, microcysts, hemorrhage, osteoclasts, and an incomplete rim of membranous ossification. Four of these benign-appearing PMTMCTs contained osteoid-like matrix. Three other PMTMCTs were hypercellular and cytologically atypical and were considered malignant. The 3 cases without known OO were histologically identical to the typical PMTMCT. Four cases did not resemble PMTMCT: 2 sinonasal HPC, 1 conventional HPC, and 1 sclerosing osteosarcoma. Three cases expressed actin; all other markers were negative. Expression of FGF-23 was seen in 17 of 21 cases by immunohistochemistry and in 2 of 2 cases by RT-PCR. Follow-up (25 cases, 6-348 months) indicated the following: 21 alive with no evidence of disease and with normal serum chemistry, 4 alive with disease (1 malignant PMTMCT with lung metastases). We conclude that most cases of mesenchymal tumor-associated OO, both in the present series and in the reported literature, are due to PMTMCT. Improved recognition of their histologic spectrum, including the presence of bone or osteoid-like matrix in otherwise typical cases and the existence of malignant forms, should allow distinction from other mesenchymal tumors. Recognition of PMTMCT is critical, as complete resection cures intractable OO. Immunohistochemistry and RT-PCR for FGF-23 confirm the role of this protein in PMTMCT-associated OO.

Epstein-Barr virus plays no role in the tumorigenesis of small-cell carcinoma of the lung

Epstein-Barr virus infection has been associated with lymphoepithelioma-like carcinoma of the lung in Asian patients. Recently, Epstein-Barr virus proteins or genomic DNAs were detected in pulmonary squamous-cell carcinoma, adenocarcinoma, and undifferentiated small-cell carcinoma in American patients. We studied 23 cases of small-cell carcinoma of the lung for evidence of Epstein-Barr virus infection by in situ hybridization, immunohistochemistry, and polymerase chain reaction methods. Of the 23 cases, 13 cases were primary small-cell carcinoma of the lung and 10 cases were metastatic small-cell carcinoma of the lung to the brain (one case), liver (two cases), and lymph nodes (seven cases). None of the 23 cases was positive for Epstein-Barr virus-encoded small nonpolyadenylated RNA (EBER)-1 by in situ hybridization. By immunohistochemistry, eight cases showed focal positivity for Epstein-Barr virus nuclear antigen-1. The positive immunostaining was focal and was observed in tumor cells, vascular endothelial cells, and lymphocytes, suggesting nonspecific staining. None of the 23 cases was positive for the transactivating immediate-early BZLF1 (ZEBRA) and latent membrane protein (LMP-1). Only one case was positive for the BamHI W region and LMP-1 gene by polymerase chain reaction assay. Some tumor cells in the BamHI W region positive case were also positive for Epstein-Barr virus nuclear antigen-1. Our study indicates that rare cases of American small-cell carcinoma of the lung may contain Epstein-Barr virus-infected cells, but it is unlikely that Epstein-Barr virus plays a role in the tumorigenesis of small-cell carcinoma of the lung.

Salivary-type neoplasms of the breast and lung

Salivary-type tumors occur in multiple sites in the human body, likely related to a basic structural homology between exocrine glands in these different anatomic areas. This paper reviews these salivary gland tumor types in breast tissue and lung. Salivary-type tumors of both breast and lung are relatively uncommon in comparison to their salivary gland counterparts. This may be attributable in part to lack of familiarity with these tumors in extra-salivary sites, and in part to histologic overlap with other primary and metastatic tumor types. Recognition of these entities is improving as the clinical and pathologic features are better delineated, and tumors are more accurately classified. Prediction of malignant behavior is not always possible in these unusual sites. In some instances, such as adenoid cystic carcinoma, behavior is known to differ considerably from that of analogous primary salivary gland tumors and in other instances there are simply too few reported cases to allow for adequate prognostication. In fact, more recent papers discuss the need to consider a spectrum encompassing benign and malignant lesions, in both breast and lung. Of course, some entities show clear-cut evidence of malignancy with documented potential for metastasis, others show bland features and well-reported benign behavior, and the less well-defined entities reside between these two extremes. The molecular pathology of salivary gland tumors has been reasonably well investigated in that location; however; there are few molecular studies devoted to salivary-type tumors of the breast and lung. This represents a potential area for future growth in further clarifying these tumors and their behavior.

Glandular inclusions in inguinal hernia sacs: morphologic and immunohistochemical distinction from epididymis and vas deferens

Glandular inclusions in inguinal hernia sacs may bear a striking resemblance to the epididymis or vas deferens. Misinterpretation as a transected functional structure may raise significant concerns regarding reproductive capability, even if encountered unilaterally. In a child, resolution of these concerns may be years away with the onset of puberty and documentation of normal sperm counts. CD10 has been shown to be present in Wolffian-type epithelium and to be absent in Mullerian-type epithelium. We hypothesized that an antibody to CD10 would react with vas deferens and epididymis and fail to react with hernia sac inclusions, most of which we thought were Mullerian duct-derived structures. Glandular inclusions in 29 hernia sacs from prepubertal males were classified histologically according to their resemblance to normal structures and analyzed for CD10 by immunohistochemistry. Inclusions resembling vas deferens had their external diameters measured and were also stained for smooth muscle actin. Thirty-one examples of normal vas deferens and 13 examples of normal epididymis were included for comparison. The inclusions were classified as vas deferens-like (9), epididymis-like (13), and Mullerian-like (7). CD10 reactivity was lacking in all vas deferens-like inclusions; their median external diameter was 0.6 mm. Of the epididymis-like inclusions, 7 of 13 were CD10 positive. The CD10-negative cases consisted of glands with well-defined stromal coats distinct from adjacent stromal coats. CD10-positive cases were more numerous, more tightly aggregated, and surrounded by less well-developed stromal coats that blended with adjacent coats. All seven Mullerian-like remnants were CD10 negative. All normal vas deferens and epididymis showed at least focal CD10 reactivity. CD10 positivity in all cases had a luminal membranous staining pattern. Both the vas deferens-like inclusions and the normal vas deferens showed strong smooth muscle actin positivity in their stromal coats. CD10 negativity and external diameter <1 mm are highly useful to distinguish vas deferens-like inclusions from true vas deferens. Epididymis-like inclusions are more problematic. Some react for CD10 and may represent aberrant Wolffian ductules. Others are CD10 negative, distinct from true epididymis, and may be of Mullerian differentiation. Mullerian-like remnants can be diagnosed on the basis of their limited number and scattered distribution. Lack of CD10 immunostaining corroborates this interpretation.

Beta-adrenergic receptor subtypes that mediate ractopamine stimulation of lipolysis

Ractopamine HCl is an beta-adrenergic receptor (betaAR) ligand that was recently approved for use in swine to enhance carcass leanness. The RR stereoisomer of ractopamine is the most active of the four stereoisomers exhibiting the highest affinity and signaling response. The RR isomer exhibits selective activation of the porcine beta2AR, which might limit the lipolytic response to ractopamine because the betaAR is the predominant subtype in swine adipocytes and may mediate most of the lipolytic response. Therefore, we determined the betaAR subtypes that mediate the lipolytic response to ractopamine in swine adipocytes. In order to confirm the predominant role of the beta1AR in porcine adipocytes, isoproterenol-stimulated lipolysis was inhibited by increasing doses of subtype-selective antagonists. Inhibition curves were biphasic using beta1AR antagonists (CGP 20712A and bisoprolol) and curve analysis indicated that both beta1AR an beta2AR contributed to lipolysis with 50 to 60% of the response coming from the beta1AR. Inhibition with the beta2AR antagonist clenbuterol revealed only one class of betaAR that closely approximated the kinetics of the beta1AR. When the RR isomer of ractopamine was the lipolytic agent, similar results to isoproterenol were observed, except that the estimated contribution of the beta1AR was 38%. That beta2AR antagonists did not detect a contribution of the beta2AR to lipolysis may indicate that the beta1AR masked the response to the beta2AR. Dose titration with the RR isomer in the presence of a saturating concentration of beta1AR or beta2AR antagonists indicated that each subtype was present in sufficient quantities to stimulate lipolysis near maximally. Data indicate that both the beta1AR and beta2AR are functionally linked to lipolysis in swine adipocytes and that ractopamine activates each subtype. The RR isomer of ractopamine stimulated adenosine 3',5'-cyclic phosphate accumulation with equal efficacy to isoproterenol through the cloned porcine beta2AR, but was only 35% as efficacious through the cloned porcine beta1AR. These data confirm the beta2AR selectivity of the RR stereoisomer, but suggest the partial agonism through the beta1AR is sufficient to activate lipolysis through both subtypes in swine adipocytes.

Stereoselectivity of porcine beta-adrenergic receptors for ractopamine stereoisomers

Ractopamine HCl is a beta-adrenergic receptor ((betaAR) ligand approved for use in swine to enhance carcass leanness. Ractopamine is produced commercially as a mixture of four stereoisomers (RR, RS, SR, SS). In order to determine which stereoisomers are active in the pig and whether they exhibit betaAR subtype selectivity, receptor affinity and adenylyl cyclase activation were determined using cloned porcine beta1- and beta2AR expressed in Chinese hamster ovary (CHO) cells. Dissociation constants (Kd) were determined by competitive displacement of [125I]iodocyanopindolol binding by ractopamine stereoisomers. The RR isomer had the highest affinity for both beta1- and betaAR (Kd of 29 and 26 nM, respectively). Dissociation constants for the other stereoisomers were higher (RS = 463 and 78 nM, SR = 3,230 and 831 nM, SS = 16,600 and 3,530 nM for the beta1- and beta2AR, respectively) relative to the RR stereoisomer. Isoproterenol stimulated adenylyl cyclase activity 600% relative to basal rates in CHO cells, regardless of betaAR subtype. Ractopamine stereoisomers did not significantly (P > 0.05) stimulate adenylyl cyclase through the beta1AR at moderate (near Kd) or high (10(-4) M) concentrations. In contrast, the RR isomer increased adenylyl cyclase activity 200 to 300% relative to basal rates through the beta2AR at moderate and hiconcentrations; the SR stereoisomer increased adenylyl cyclase activity nearly 100%. Neither the RS nor SS stereoisomers were effective in activating adenylyl cyclase activity through the beta2AR. A pattern of stereoselective activation similar to that for adenylyl cyclase also was exhibited for lipolysis using porcine adipocytes. The RR stereoisomer was equal to isoproterenol in stimulating lipolysis, whereas the SR isomer was 50% as effective; the RS and SR stereoisomers did not stimulate lipolysis in porcine adipocytes. The porcine betaAR exhibited stereoselectivity toward ractopamine stereoisomers with the RR isomer exhibiting the highest affinity for the (beta1- and beta2AR. In contrast, ractopamine stereoisomers seemed to be more effective at eliciting adenosine cyclic 3',5'-phosphate responses from beta2AR than beta1AR. The RR isomer ilikely the functional stereoisomer of ractopamine, but its effectiveness may be compromised by the presence of competing isomers, in particular the RS stereoisomer.

Evaluation of surgical margins in anatomic pathology: technical, conceptual, and clinical considerations

Virtually all anatomic pathologists are involved in the assessment of tissue margins in surgical procedures that are performed for malignant diseases. The natural tendency to view this process as uncomplicated has, in recent years, been countered by a body of literature on the biological milieu of the marginal zone. Moreover, empirical clinical information has shown that "negative" and "positive" marginal status has an imperfect correlation with risk of recurrent disease in several organ systems and in reference to various tumor types. Problems also remain regarding the optimal techniques for pathologic sampling of margins; the possible roles, if any, of adjuvant (eg, immunohistologic and "molecular") procedures for margin evaluation, and reporting motifs for selected surgical resections. This review considers conceptual data now available on surgical margins, provides a working approach to the generic assessment of marginal surfaces, and presents organ- and tumor- specific information pertaining to this area of practice.

Interpretation of RET immunostaining in follicular lesions of the thyroid

We applied monoclonal antibodies against RET and cytokeratin 19 (CK19) to the following tumor sections: classic papillary carcinoma (PC), 16; Hürthle-type PC (HPC), 1; sclerosing PC with nodular fasciitis-like stroma (SPC), 1; PC, follicular variant (FVPC), 12; follicular adenoma (FA), 9; Hürthle cell adenoma (HA), 4; Hürthle cell carcinoma (HC), 3; and follicular carcinoma (FC), 7. CK19+ tumors included 16 PCs, 1HPC, 1SPC, 11 FVPCs, 7 FAs, 4 FCs, and 1HC. RET+ tumors included 4 HAs, 3 HCs, 1HPC, 12 PCs, 7 FVPCs, and 2 FAs. Reverse transcriptase-polymerase chain reaction (RT-PCR) revealed a RET transcript in 6 Hürthle cell lesions. RET immunoreactivity is less sensitive and specific for PC than CK19. CK19 is useful for identifying PC, although only lesions with diffuse, intense staining should be considered positive. The detection of RET protein by immunohistochemical analysis was corroborated by the presence of the RET transcript by RT-PCR. Further study is warranted to determine whether this represents activation by gene fusion or some other mechanism in this subset of thyroid neoplasms.

Gleason scores of prostate biopsy and radical prostatectomy specimens over the past 10 years: is there evidence for systematic upgrading?

BACKGROUND

With the advent of the prostate specific antigen (PSA) assay, an increased detection rate of prostate carcinoma has ensued. This has been associated with a downward stage migration. In contrast, grade has shifted heavily toward moderate differentiation. The authors sought to test the hypothesis that such changes in grade in part may be because of trends among pathologists to upgrade similar specimens over time.

METHODS

Two expert genitourinary pathologists regraded 23 prostate biopsies and 15 radical prostatectomy specimens during a 3-year period (1989-1991). Each pathologist then regraded 32 prostate biopsies and 15 radical prostatectomies from 1998 to 2000. For both time periods, each pathologist regraded only specimens that they personally had graded initially. All specimens were scored using the Gleason system, the predominant system used in describing prostate carcinoma grade. In evaluating original and regraded scores, the authors classified score changes between less than or equal to 6 and greater than or equal to 7 or between 7 and greater than or equal to 8 as significant because such changes have a high probability of altering clinical management. The results were analyzed using the two-tailed Fisher exact test.

RESULTS

Of 23 prostate biopsies from 1989 to 1991, 10 of 23 (44%) had a clinically significant Gleason score change when regraded, whereas 2 of 15 (13%) radical prostatectomy specimens from the same period had a clinically significant Gleason score change. A significant change in the distribution of biopsy Gleason scores on regrading was observed (P < 0.04). In comparison, when the prostate biopsies from 1998-2000 were regraded, 10 of 32 (31%) had a clinically significant grade change. Radical prostatectomy specimens from the same period revealed 3 of 15 (20%) with a clinically significant grade change. After regrading the biopsies from 1989-1991, 8 of 23 (35%) of were upgraded, whereas 2 of 23 (9%) were downgraded. In comparison, of the biopsies with significant changes from 1998 to 2000, 3 of 32 (9%) were upgraded, whereas 7 of 32 (22%) were downgraded. Of the radical prostatectomy specimens with significant change, only 2 of 15 from each period were upgraded. Significant upgrading (P < 0.005) occurred only in the biopsy specimens from 1989 to 1991.

CONCLUSIONS

The authors' data suggest that rates of upgrading and downgrading of biopsy specimens differ between the 1989-1991 cases and the 1998-2000 cases, with the 1989-1991 samples exhibiting a significant change toward higher grades. Although not excluding the possibility of a change in the biology of prostate carcinoma over time, these findings suggest that the apparent trend toward higher biopsy grades in part may be because of how pathologists interpret these specimens today as compared with 10 years ago. Therefore, outcome studies including a biopsy Gleason score from older specimens as a risk variable have a significant chance of being vulnerable to this phenomenon. Based on the authors' data, all such specimens should undergo rereview.

Quantitative analysis of beta-adrenergic receptor subtypes in pig tissues

The density and distribution of beta1- and beta2-adrenergic receptors (betaAR) in porcine adipocytes, skeletal muscle, heart, lung, and liver were investigated using competitive displacement of ligand binding with subtype-selective ligands. Three experimental approaches were used to estimate the distribution of betaAR subtypes in adipocytes. Two approaches involved simultaneous linear regression analysis of multiple competitive displacement curves with the beta1AR-selective antagonist CGP 20712A and the beta2AR-selective ligand BRL 37344. For the third approach, radioligand saturation assays were perfomed using a concentration of CGP 20712A that completely blocked the beta1AR. All three approaches indicated the presence of multiple betaAR subtypes in porcine adipocytes and gave similar estimates for the proportion of these subtypes. Saturation assays in the presence of the beta1AR blocker CGP 20712A were conducted to determine the distribution of the betaAR subtypes in skeletal muscle, heart, lung, and liver. The proportions of the beta1AR and beta2AR were 81:19, 59:41, 72:28, 58:42, and 50:50 for adipose, skeletal muscle, heart, lung, and liver, respectively. These estimates based on receptor protein were consistent with published estimates of mRNA abundance in pig tissues but differ from estimates for other species. The predominance of beta1AR in adipocytes and skeletal muscle may contribute to the reduced efficacy of select betaAR agonists in pigs compared to other species because most of the ligands evaluated in growth studies are purported to be beta2AR selective. The density of the betaAR varied among tissues in the following order: heart = lung > adipocytes > skeletal muscle or = liver.

Neuroectodermal neoplasms of the head and neck with emphasis on neuroendocrine carcinomas

Tumors exhibiting neuroectodermal differentiation occur throughout the body, and the diverse tissues of the head and neck give rise to a wide assortment of these neoplasms. Neuroectodermal neoplasms may be divided into lesions showing primarily epithelial differentiation (Group I, neuroendocrine carcinomas) and a more diverse group (Group II) of nonepithelial neoplasms. This article reviews these neuroectodermal tumors of the head and neck with emphasis on the neuroendocrine carcinomas and their nomenclature. The author believes that with regard to Group I tumors, the older terminology of carcinoid, atypical carcinoid, and small cell carcinoma should be replaced by subclassifications of well-differentiated, moderately differentiated, and poorly differentiated neuroendocrine carcinoma. The latter category should be further subdivided into small cell and large cell variants. Neuroendocrine carcinomas, particularly the moderately differentiated subtype, are often underdiagnosed in the head and neck region. In the larynx, these tumors are the most common form of nonsquamous carcinoma. Poorly differentiated neuroendocrine carcinoma of small cell type is most common in the salivary glands but can occur elsewhere in the region. The large cell subtype of poorly differentiated neuroendocrine carcinoma has not been well documented in this region. However, the most likely candidate for this tumor category is the so-called sinonasal undifferentiated carcinoma. Group II tumors discussed include olfactory neuroblastoma, malignant melanoma, and Ewing's sarcoma. In addition, differential diagnostic problems related to Group I and II tumors are reviewed in detail. This article reviews and updates our understanding of neuroectodermal neoplasms arising in the head and neck. The focus is on tumors that exclusively involve this region or show a strong predilection to occur here.

Neuroendocrine neoplasms of the lung

Neuroendocrine tumors of the lung continue to be difficult nosologic and diagnostic problems, centering on the time-honored terms of "carcinoid," "atypical carcinoid," and "small cell carcinoma." Problems that are encountered in the classification of such neoplasms revolve around the differing criteria that have been advanced for their definition and variable application of such criteria in common practice. This review considers the epithelial and nonepithelial lesions of the lung that may demonstrate neuroendocrine and neuroectodermal differentiation. A proposal is made for a simplified system of classifying the epithelial tumors, dividing them into 3 grades with appended descriptive modifiers.

Effects of conjugated linoleic acid on the belly firmness and fatty acid composition of genetically lean pigs

A study of the effects of conjugated linoleic acid (CLA) on the belly firmness and fatty acid composition of genetically lean pigs was conducted. From 75 to 120 kg live weight, 30 gilts were allowed ad libitum access to a corn-soybean meal diet supplemented with either 1% CLA oil (CLA-60) or 1% sunflower oil (SFO) or were fed the sunflower oil-supplemented diet restricted to the amount consumed by pigs fed the CLA-60 diet (RSFO). Conjugated linoleic acid oil consists of 60% positional and geometric isomers of CLA. Pigs fed SFO exhibited higher average daily gains (0.98 vs 0.80 kg/d, P < 0.01) than RSFO-fed pigs, but there were no effects of dietary treatment on feed intake or feed efficiency. Dietary treatment did not affect (P > 0.05) backfat thickness or longissimus muscle area. Bellies of gilts fed CLA-60 were subjectively evaluated to be firmer (2.91 vs 2.43 or 2.07 +/- 0.13, P < 0.01) than those of SFO- or RSFO-fed gilts, respectively. The longissimus muscle of gilts fed CLA-60 contained more saturated fatty acids (39.77 vs. 36.04 or 36.73 +/- 0.74%, P < 0.001) and less unsaturated fatty acids (60.23 vs 63.96 or 63.27 +/- 0.74%, P < 0.001) than that of gilts fed SFO or RSFO, respectively. The belly fat of gilts fed CLA-60 contained more saturated fatty acids (44.45 vs. 37.50 or 36.60 +/- 0.46%, P < 0.001) and less unsaturated fatty acids (54.78 vs. 61.75 or 62.47 +/- 0.46%, P < 0.001), resulting in lower iodine values (57.69 vs 66.37 or 65.62 +/- 0.91, P < 0.001) than that of gilts fed SFO or RSFO, respectively. Gilts fed CLA-60 accumulated more CLA in the longissimus muscle (0.55 vs 0.09 or 0.09 +/- 0.03%, P < 0.01) and belly fat (1.56 vs. 0.13 or 0.13 +/- 0.15%, P < 0.001) than did gilts fed SFO or RSFO, respectively. Dietary treatment did not affect (P > 0.05) 24-h pH, drip loss or subjective quality evaluations of the longissimus muscle. The effect of supplemental CLA to improve belly firmness is of practical significance and may provide a nutritional solution to carcass fat and belly firmness problems, thereby enhancing the overall value of extremely lean carcasses.

Immunohistochemical differential diagnosis of pleural effusions, with emphasis on malignant mesothelioma

The immunohistochemical diagnosis of atypical epithelial proliferations in pleural fluid is a challenging topic in cytopathology and surgical pathology. Mesothelioma may be simulated clinically and radiologically by several other nonneoplastic and neoplastic disorders, mandating that strict histologic, histochemical, immunohistochemical, and ultrastructural guidelines be followed for its diagnosis. Because of its availability to most laboratories, immunohistochemistry has emerged as the most commonly used procedure for the diagnosis of pleural malignancies. This review considers the current status of that investigative modality, with particular attention to lesions that are suspected to be mesothelial.

Mucoepidermoid carcinoma: a clinicopathologic study of 80 patients with special reference to histological grading

We sought to review our experience with salivary mucoepidermoid carcinoma (MEC) over two decades to confirm the validity and reproducibility of histologic grading and to investigate MIB-1 index as a prognosticator. Diagnosis was confirmed on 80 cases, and chart review or patient contact was achieved for 48 patients, with follow-up from 5 to 240 months (median 36 months). Immunohistochemistry with citrate antigen retrieval for MIB-1 was performed on a subset of cases. Kaplan-Meier survival curves were generated for each stage, site, and grade according to our proposed grading system. To address the issue of grading reproducibility, 20 slides were circulated among five observers, without prior discussion; slides were categorized as low-, intermediate-, or high-grade according to one's "own" criteria, and then according to the AFIP criteria proposed by Goode et al.10 Weighted kappa (kappa) estimates were obtained to describe the extent of agreement between pairs of rating. The Wilcoxon signed rank test or the Friedman test as appropriate tested variation across ratings. There was no gender predominance and a wide age range (15-86 years, median 49 years). The two most common sites were parotid and palate. All grade 1 MECs presented as Stage I tumors, and no failures were seen for this category. The local disease failure rates at 75 months for grades 2 and 3 MEC were 30% and 70%, respectively. Tumor grade, stage, and negative margin status all correlated with disease-free survival (DFS) (p = 0.0091, 0.0002, and 0.048, respectively). The MIB index was not found to be predictive of grade. Regarding the reproducibility of grading, the interobserver variation for pathologists using their "own" grading, as expressed by the kappa value, ranged from good agreement (kappa = 0.79) to poor (kappa = 0.27) (average kappa = 0.49). A somewhat better interobserver reproducibility was achieved when the pathologists utilized the standardized AFIP criteria (average kappa = 0.61, range 0.38-0.77). This greater agreement was also reflected in the Friedman test (statistical testing of intraobserver equality), which indicated significant differences in using one's own grading systems (p = 0.0001) but not in applying the AFIP "standardized" grading (p = 0.33). When one's own grading was compared with the AFIP grading, there were 100 pairs of grading "events," with 46 disagreements/100 pairs. For 98% of disagreements, the AFIP grading "downgraded" tumors. This led us to reanalyze a subset of 31 patients for DFS versus grade, for our grading schema compared with the AFIP grading. Although statistical significance was not achieved for this subset, the log rank value revealed a trend for our grading (p = 0.0993) compared with the Goode schema (p = 0.2493). This clinicopathologic analysis confirms the predictive value of tumor staging and three-tiered histologic grading. Our grading exercise confirms that there is significant grading disparity for MEC, even among experienced ENT/oral pathologists. The improved reproducibility obtained when the weighted AFIP criteria were used speaks to the need for an accepted and easily reproducible system. However, these proposed criteria have a tendency to downgrade MEC. Therefore, the addition of other criteria (such as vascular invasion, pattern of tumor infiltration [i.e., small islands and individual cells vs cohesive islands]) is necessary. We propose a modified grading schema, which enhances predictability and provides much needed reproducibility.

The structures of anthranilate synthase of Serratia marcescens crystallized in the presence of (i) its substrates, chorismate and glutamine, and a product, glutamate, and (ii) its end-product inhibitor, L-tryptophan

The crystal structure of anthranilate synthase (AS) from Serratia marcescens, a mesophilic bacterium, has been solved in the presence of its substrates, chorismate and glutamine, and one product, glutamate, at 1.95 A, and with its bound feedback inhibitor, tryptophan, at 2.4 A. In comparison with the AS structure from the hyperthermophile Sulfolobus solfataricus, the S. marcescens structure shows similar subunit structures but a markedly different oligomeric organization. One crystal form of the S. marcescens enzyme displays a bound pyruvate as well as a putative anthranilate (the nitrogen group is ambiguous) in the TrpE subunit. It also confirms the presence of a covalently bound glutamyl thioester intermediate in the TrpG subunit. The tryptophan-bound form reveals that the inhibitor binds at a site distinct from that of the substrate, chorismate. Bound tryptophan appears to prevent chorismate binding by a demonstrable conformational effect, and the structure reveals how occupancy of only one of the two feedback inhibition sites can immobilize the catalytic activity of both TrpE subunits. The presence of effectors in the structure provides a view of the locations of some of the amino acid residues in the active sites. Our findings are discussed in terms of the previously described AS structure of S. solfataricus, mutational data obtained from enteric bacteria, and the enzyme's mechanism of action.

Impact of second opinion pathology in the definitive management of patients with bladder carcinoma

BACKGROUND

The accurate diagnosis, staging, and grading of bladder neoplasms depend heavily on the interpretation of biopsies and transurethral resection (TUR) specimens. Although many centers require review of outside pathologic material before definitive treatment such as radical cystectomy, the authors are unaware of data supporting the utility of this approach in urothelial (transitional cell) carcinoma. The authors therefore examined the clinical and cost impact of pathologic review on patients referred to an academic urology department for treatment of bladder neoplasia.

METHODS

The pathologic material from 97 patients referred to an academic center for evaluation of urothelial carcinoma of the bladder from July 1996 to July 1999 was reviewed. This material was received from 30 community hospitals and 4 academic centers. The 97 patients had undergone 131 (mean, 1.35; range, 1-10) biopsies or TUR procedures before referral. Surgical pathologists at the authors' institution reviewed all outside patient material, and discordant cases were rereviewed by one of the authors (S.E.M), an experienced genitourinary pathologist. Follow-up chart review was performed in discordant cases to determine clinical and pathologic outcomes.

RESULTS

Upon review at the authors' institution, 24 of 131 (18%) specimens with a referring diagnosis of urothelial carcinoma exhibited significant discrepancies with regard to the diagnosis, stage, grade, or tumor histologic type made at the outside institution. Four tumors (3%) were found to be nonurothelial neoplasms. Five specimens (4%) were judged inadequate for staging because they contained no muscularis propria. Three patients were upstaged, including two patients shown to have muscle invasive disease. Eight patients were downstaged, including two patients referred with purported muscle invasive disease who were determined to have only superficial disease on pathology review. Two patients initially thought to have carcinoma in situ (tumor in situ [Tis]) showed no evidence of Tis on pathology review. One patient with purported muscle invasive disease was shown to have only metaplasia, and one patient had a highly significant change in tumor grade. As a result of the pathology review, five radical cystectomies were avoided, whereas five repeat TUR procedures were recommended for inadequate staging. One patient shown to have muscle invasion on pathology review proceeded directly to cystectomy, avoiding a planned repeat TUR. A cystectomy also was recommended to a second patient who was shown to have invasive disease by the pathology review. Pathology review of 131 specimens resulted in net savings of $86,176 or $658 per TUR reviewed.

CONCLUSIONS

The review of bladder pathologic materials before definitive therapy can impact clinical decisions significantly and can reduce overall expenditures for the management of this cohort of bladder carcinoma patients.