ANATOMIC PATHOLOGY

   

The Critical Role of Histology in an Era of Genomics and Proteomics: A Commentary and Reflection

Nathwani, Bharat N.  Sasu, Sebastian J. et al

The role of histologic examination in lymphoma diagnosis has been called into question by proponents of new technologies, such as genomics and proteomics. We review the history and salient features of morphologic evaluation in lymphoid diseases, and discuss the general and specific limitations of mature ancillary techniques, such as immunohistochemistry, flow cytometry, and molecular studies. We then speculate on the future relationship between morphology and the new genomic and proteomic technologies as they become integrated into clinical practice.

“Morphology is always important, and some diseases are primarily defined by morphology with immunophenotype as backup in difficult cases.”—Nancy Harris, et al.

In light of these many issues, we have tried to elucidate the role of the histopathologist and histologic examination in general, in this era of genomics and proteomics. As in the WHO, we advocate a combination of morphologic examination and ancillary diagnostic studies as the most appropriate approach to diagnosis.

In any newly biopsied patient, there is no question that morphology will remain an integral part of the diagnostic process. At the bare minimum, morphology will be required to dictate the subsequent diagnostic testing that will be necessary to establish the most accurate diagnosis.

KEY POINTS

 

1. The new and evolving technologies of genomics and proteomics have ushered in a revolution in our approach to diagnosis, prognosis, and therapy, and may ultimately replace some of the more mature technologies such as cytogenetics, flow cytometry, immunohistochemistry, and conventional molecular testing in selected disorders.

 

2. Current technologies, such as immunohistochemistry, flow cytometry, cytogenetics, FISH, and conventional molecular testing by PCR have well-defined and well-studied limitations to their use in the establishment of a final diagnosis, determination of prognosis, and guidance of therapy.

 

3. Because of the limitations of the nascent genomic and proteomic technologies, these techniques should not be used as the primary diagnostic modalities in a patient biopsied for the first time.

 

4. None of the technologies described above have definitive and exclusive diagnostic superiorities over all the others, therefore an integrated approach to diagnosis should be attempted, using all appropriate and available techniques of investigation to reach an accurate final diagnosis, to provide patient-specific prognostic information, and to recommend targeted, patient-specific therapy, if available.

   

5. Careful and critical histologic examination of tissue sections remains the most important first diagnostic step in the evaluation of the pathologic specimen and the determination of what ancillary tests are required to reach a final diagnosis.

Advances in Anatomic Pathology, Volume 14(6), November 2007, pp 375-400

 

Sentinel Lymph Node Detection in Early Stage Uterine Cervix Carcinoma: A Systematic Review

van de Lande J, Torrenga B, Raijmakers PG et al

OBJECTIVE: The aim of this study was to systematically review the diagnostic performance of Sentinel Node (SN) detection for assessing the nodal status in early stage cervical carcinoma, and to determine which technique (using blue dye, Technetium-99m colloid (99mTc), or the combined method) had the highest success rate in terms of detection rate and sensitivity.

METHODS: A comprehensive computer literature search of English language studies in human subjects on Sentinel Node procedures was performed in MEDLINE and EMBASE databases up to July 2006. For each article two reviewers independently performed a methodological qualitative analysis and data extraction using a standard form. Pooled values of the SN detection rate and pooled sensitivity values of the SN procedure are presented with a 95% confidence interval (95% CI) for the three different SN detection techniques.

RESULTS: We identified 98 articles, and 23 met the inclusion criteria, comprising a total of 842 patients. Ultimately, 12 studies used the combined technique with a sensitivity of 92% (95% CI: 84-98%). Five studies used 99mTc-colloid, with a pooled sensitivity of 92% (95% CI: 79-98%; p=0.71 vs. combined technique), and four used blue dye with a pooled sensitivity of 81% (67-92%, p=0.17 vs. combined technique). The SN detection rate was highest for the combined technique: 97% (95% CI: 95-98%), vs. 84% for blue dye (95% CI: 79-89%; p<0.0001), and 88% (95% CI: 82-92%, p=0.0018) for 99mTc colloid. CONCLUSION: SN biopsy has the highest SN detection rate when 99mTc is used in combination with blue dye (97%), and a sensitivity of 92%. Hence, according to the present evidence in literature the combination of 99mTc and a blue dye for SN biopsy in patients with early stage cervical cancer is a reliable method to detect lymph node metastases in early stage cervical cancer.

Gynecol Oncol. 2007 Sep;106(3):604-13. Epub 2007 Jul 12

 

Patterns of Histological Change in Liver Disease: My Approach to ‘Medical’ Liver Biopsy Reporting

 A C Bateman

   

The  aim  of  this  review  was  to  emphasize  the  benefit of  a  methodical  approach  to  ‘medical’  liver  biopsy reporting and to illustrate that recognition of patterns of  disease  can  greatly  aid  correct  interpretation  of these  often-complex  specimens.  This applies both to assessment of the liver architecture and to evaluation of the likely disease aetiology. Therefore, a great deal of  information  can  be  obtained  by  examining  biopsy material  at  low-  and  medium-power  magnification, prior to confirming detailed features with high-power examination.  A  range  of  recommended  special  histochemical  stains  that  personal  experience  has  shown to be valuable is included. Emphasis is also placed on the absolutely key requirement for appropriate know- ledge of the clinical situation within which the biopsy specimen was taken.

 Introduction

 The  interpretation  of  liver  biopsy  specimens  for  the presence  of  ‘medical’  liver  disease  takes  place  within both specialist and non-specialist units, and some of the latter  may  see  only  a  small  number  of  biopsies  each year.  The use of a structured approach to the examination of liver biopsy specimens should allow reporting pathologists to gain a more confident opinion about the nature of the disease process present. In common with many  organs,  the  liver  exhibits  a  limited  number  of major  histopathological  responses  to  tissue  damage, and recognition of these is a major step in assembling an  appropriate  differential  diagnosis.  This review will demonstrate these principles within a range of the more commonly encountered liver diseases apart from transplant-related liver pathology. 

Importance of Clinical Information and Multidisciplinary Working

 The  practice  of  liver  pathology  is  one  in  which  an appreciation  of  the  clinical  situation  in  which  the specimen  has  been  taken  is  a  key  element  in  the formation  of  an  accurate  opinion.  Sufficient  clinical information  should  be  available  to  the  pathologist  at the  time  of  examination  of  the  biopsy  specimen  to enable interpretation of the histopathological features in the appropriate clinical context. Radiologists perform an increasing number of liver biopsies under ultrasound guidance and, in my experience, this can impede the flow of clinical information from the hepatologist to the pathologist. In this situation, relevant information may sometimes be gleaned from the hospital computer systems,  but  the  ideal  situation  is  the  presence  of  a regular  liver  disease  clinicopathological  meeting  at which biopsy specimens can be presented and discussed with the hepatologists.

 

Multiple Aetiologies and Overlap Syndromes

 Although many patients with liver disease possess one dominant pathological process, a significant proportion will show evidence of more than one aetiological factor. It  is  always  very  important  to  bear  this  possibility  in mind  when  examining  a  specimen.  For  example,  it might be easy to miss the presence of hepatitis C virus infection  when  examining  a  specimen  from  a  patient with  alcoholic  liver  disease  (ALD)  unless  due  consideration  is  given  to  the  density  of  the  portal  tract inflammation and the presence of interface hepatitis.

 

Recommended Stains  

Access to high-quality haematoxylin and eosin (H&E)-stained   sections   and   a   good   range   of   additional histochemical stains is a prerequisite for liver biopsy reporting.  Each  centre  will  use  a  different  panel  of stains within their routine ‘liver set’, but in Southampton  General  Hospital  the  H&E  stain  is  supplemented with            the following:            reticulin, hepatitis-associated antigen (HAA)   orcein,   haematoxylin   van   Gieson (HVG),  Perl’s,  periodic acid-Schiff  (PAS) and diastase periodic acid–Schiff (DPAS). We also prepare a second H&E-stained level, which is taken after the sections for the special histochemical stains.  The key purpose for each of the stains is stated in Table 1.

 

Normal Anatomy

 The   traditional   means   of   considering   the   micro-anatomy  of  the  liver  is  in  terms  of  the  lobule,  i.e.  a structural  unit  centred  on  a  central  vein  (terminal hepatic  vein)  and  pentagonal  or  hexagonal  in  shape with  a  portal  tract  at  each  corner  of  the  polygon. However,   a   more   modern   approach   would be to consider the liver in functional terms via the concept of an acinus, i.e. a unit centred on a portal tract with terminal hepatic veins at the periphery.  The acinus may be divided into zones thus: zone 1, periportal; zone 2, mid-acinar; and zone 3, perivenular (Figure 1A,B).

 

A Systematic Approach

Examining a Biopsy Specimen before Reading Clinical History

 Although it is essential to interpret a liver biopsy specimen in the context of the clinical situation, it may be helpful to undertake a preliminary examination of liver biopsy reporting the slides before reading the stated clinical history. This allows an initial assessment of the overall pattern of disease without preconceptions that might arise if the nature of the clinical history is known.

 

Table 1. A panel of histochemical stains for medical liver biopsy reporting

 

 

HAA-  Hepatitis-associated antigen;

PAS-   periodic acid–Schiff;

DPAS- diastase periodic acid–Schiff.

 

Low-Power Assessment

 Initial assessment of the specimen at low power will provide information about the adequacy of the biopsy, overall architecture of the liver, the presence and distribution of fatty change and the presence of inflammation within the portal tracts and parenchyma. Careful assessment at this stage will greatly aid correct interpretation, in that the broad category of disease process may already become apparent. Although one can start this phase of the examination with the H&E stain, an appreciation of the architecture requires one or more connective tissue stains and therefore it is worthwhile perusing the reticulin and⁄or HVG stain at low power before returning to the H&E preparation.

 

 Assessment of Biopsy Specimen Adequacy

 A liver biopsy specimen represents approximately 1⁄50000 of the total liver volume and there is therefore always the possibility of sampling error complicating clinical interpretation. Clearly, sampling error is likely to be most significant during the assessment of diseases with a patchy distribution—for example, the characteristic lesions of chronic inflammatory biliary tract diseases. Architectural disturbances such as macronodular cirrhosis and incomplete septal cirrhosis may also be difficult or impossible to diagnose with certainty within a single liver biopsy specimen. These difficulties are some of the important reasons for interpreting specimen appearances in the knowledge of clinical and radiological data. There is no clear consensus on the minimum size of a specimen required for accurate diagnosis: recommendations have ranged between a content of at least six to eight portal tracts and length 15 mm to a requirement for at least 11 portal tracts within a specimen of at least 20–25 mm. Transjugular liver biopsy can also provide adequate specimens, especially if at least three passes are used, although in the experience of the author there is a tendency to use a finer biopsy needle, which creates narrow specimens in which interpretation of tissue architecture can be difficult.

 

Detailed Examination and Report Construction

 Once a low-power assessment has been made, the major disease process (if any) may well already be apparent. Higher power examination will then allow confirmation of the pathological features and a search for those that are only visible at greater magnification. The precise order in which medium- and high-power examination takes place is not critical, but it is important to devise a systematic approach so that all elements of the specimen are examined. The following is a suggested approach:

 

1. Size of biopsy specimen and number of portal tracts
2. Overall architecture
3. Portal tracts
4. Parenchyma
5. Initial special stains: reticulin, Perl’s, DPAS, orcein
6. Additional special stains, e.g. rhodanine, immuno- histochemistry.

 

Assessment of Architecture

 The overall architecture of the liver is clearly the key element in determining the stage of a liver disease and is usually the feature uppermost in the mind of the clinician. Advanced micronodular cirrhosis is easy to identify even on H&E staining, whereas early fibrosis requires careful examination of connective tissue stains. Micronodular cirrhosis is characterized by the formation of nodules that are smaller than the size of an individual lobule (usually < 3 mm in diameter). The most common cause would be ALD and, in keeping with this, the fibrous septa usually involve both the terminal hepatic veins and the portal tracts. Residual hepatic veins may therefore be difficult to identify. The nodules occurring in macronodular cirrhosis are larger than an individual lobule and the evidence for cirrhosis within a single liver biopsy specimen may be subtle; for example, there may be one or more septa traversing the specimen and possibly involving a portal tract. In this situation, the presence of liver cell cords greater than one cell in thickness and indicating regenerative change can provide useful supporting evidence for the presence of cirrhosis. Although liver biopsy usually provides useful information on architecture, sampling error can potentially lead to difficulty in determining the stage of a liver disease, especially when macronodular cirrhosis is a possible diagnosis. The term ‘incomplete septal cirrhosis’ is sometimes used to describe an abnormal liver architecture characterized by the presence of fine septa extending from portal tracts, but without obvious linking of portal tracts. The hepatocyte plates may be increased in thickness and sinusoidal dilation may be seen. There is usually very little inflammation or other features to help with the determination of aetiology. The cause of incomplete septal cirrhosis is unclear; a  partly ‘regressed’ cirrhosis and a reaction to abnormalities in blood flow have been suggested as potential under-lying  factors. Incomplete septal cirrhosis is distinct from nodular regenerative hyperplasia, but differentiation between these two processes may be impossible on liver biopsy. When cirrhosis is not present, patterns of fibrosis may still be very helpful in suggesting possible aetiologies. For example, portal tract expansion, in which the edges of the enlarged portal tracts are smooth, is seen in chronic biliary tract disease, whereas perisinusoidal fibrosis is characteristic of fatty liver disease. The latter is classically present around terminal hepatic veins (and may be segmental, i.e. involve only part of the circumference of the veins when early), but is also not uncommonly seen at the edges of portal tracts (periportal fibrosis). When the latter is present together with portal tract inflammation, tracking of lymphocytes along fine perisinusoidal fibrous bands can mimic interface hepatitis and lead to an erroneous opinion that a second inflammatory process is present. The chance of this misinterpretation can be minimized by careful assessment of the H&E stain alongside those that highlight matrix, especially the HVG and DPAS.

 

The orcein stain is extremely useful for confirming the presence of mature connective tissue, in which orcein-positive elastic fibres appear around 3 months following the initiation of fibrosis. This is particularly useful in disease processes characterized by chronicity and acute exacerbations such as autoimmune hepatitis. In this situation, parenchymal foci showing reticulin condensation may occur following acute hepatocellular death and loss (i.e. collapse), which will be orcein-negative, or as a result of fibrous scarring, which will be orcein-positive if established. The pattern of orcein positivity is also useful in that the fine orcein-positive fibres that typify established but pathological fibrosis are distinct from the coarser fibres of the original portal tracts, and this aids the identification of lesser degrees of portal tract fibrosis. The HVG method also stains mature collagen and, although it does not highlight individual elastic fibres like the orcein stain, it is particularly good at revealing perisinusoidal fibrosis and fine septa.

 

Conclusion  

Successful liver biopsy reporting requires a systematic approach to the examination of biopsy specimens and access to reliable and high-quality histochemical and immunohistochemical stains. Although the histological pattern of liver disease often indicates the likely broad category of diagnosis, the ability to report biopsies with access to a full clinical history is vital if the full clinical value is to be achieved from each specimen. This can be achieved only with close clinicopathological liaison and, ideally, with regular clinical meetings at which liver specimens are presented and discussed.  

Histopathology 2007, 51, 585–596. DOI: 10.1111/j.1365-2559.2007.02765.x

 

Frozen Section Evaluation Does Not Alter Surgical Decisions in Thyroid Neoplasms With Inconclusive FNA Diagnosis: Presented at ASCP

By Lexa W. Lee

NEW ORLEANS, LA -- October 26, 2007 -- Intraoperative frozen sections (FS) of thyroid lesions are not useful for preoperative fine needle aspiration (FNA) diagnosis of thyroid neoplasms, according to findings presented here at the 2007 annual meeting of the American Society of Clinical Pathology (ASCP).

Surgeons continue to disagree about whether a frozen section of thyroid lesions would alter the operative decision and justify a change in surgical management of these cases, said Purva Gopal, MD, Pathology Resident, University of Louisville, Louisville, Kentucky, United States.

The study was done to determine the role of FS in thyroid lesions with inconclusive FNA diagnoses and their usefulness in intraoperative decision making. The investigators retrospectively reviewed the records of 38 patients with inconclusive diagnoses rendered by FNA between 2001 and 2006.

From this sample, three categories were defined based on the FNA diagnosis: follicular neoplasm (50%), suspicious for malignancy (18.5%), and non-diagnostic (31.5%).

Patients were hen also evaluated according to the availability of intraoperative FS. Results of both FNA and FS were then compared with the final pathological diagnosis.

There were 28 patients in the FS group and 10 in the non-FS group. Specimens without histology followup were excluded. The FS were given one of three diagnoses: benign (18%), deferred (75%), malignant (7%).

Among the FS patients, 28.5% showed thyroid carcinoma on permanent histology. Of these eight cases, six diagnoses were deferred on FS and two were diagnosed malignant on FS.

In the 10 non-FS group, 50% showed thyroid carcinoma on permanent histology, three of them received a lobectomy, and two had total/subtotal thyroidectomy without neck dissection.

Of the patients with non-diagnostic FNA, 87.5% had FS. Of these eight cases, seven had diagnoses deferred on FS and one was diagnosed to be benign on FS.

FS did not alter the operative decision in any patient with preoperative inconclusive FNA diagnosis.

Dr. Gopal said, "We concluded that intraoperative FS is not useful for a preoperative FNA diagnosis of neoplasm."

[Presentation title: Clinical Utility of Frozen Section Evaluation in Patients Undergoing Surgery for Nodular Thyroid Disease with Inconclusive FNA Diagnosis. Poster 24]

 

GENOMICS AND PROTEOMICS

 

Gender-Related Hormonal Risk Factors for Oral Cancer

 Suba Z.

Oral cancer (OC) is a neoplasm with fairly high male to female ratio in most populations. The conspicuously lower incidence of this tumor among women than man is suggestive of certain endocrine involvement in its development. The aim of the present case-control study was to clarify the origin of this gender-specific risk of OC incidence. 2660 inpatients (530 females and 2130 males) with squamous cell OC at the Department of Oral and Maxillofacial Surgery were included in a case-control study. Smoking, alcohol consumption, elevated fasting serum glucose level and menopausal histories of female cases were registered. Smoking and excessive alcohol intake proved to be strong risk factors for OC both in the male and female group. However, moderate alcohol consumption was a weaker risk factor for male patients, and it presented no risk for female cases. Elevated fasting glucose level was not a demonstrable OC risk factor among males, however, it proved to be strong risk factor for OC among female patients, especially in gingival cancer cases. The almost exclusively postmenopausal state of female OC patients and the long mean interval (17 years) between their menopause and OC diagnosis suggested an important role of estrogen deficiency in OC epidemiology. The significantly younger mean age at menopause and the significantly higher rate of hysterectomy among female OC cases in comparison with their controls also support the estrogen deficiency hypothesis. This novel hypothesis of estrogen deficiency and elevated fasting glucose as risk factors for OC in postmenopausal women may provide new insights into the etiology of oral malignancies.

Pathol Oncol Res. 2007;13(3):195-202. Epub 2007 Oct 7.

CYTOPATHOLOGY

Needle Core Biopsy Characteristics Identify Patients at Risk of Compromised Margins in Breast Conservation Surgery

Mary F Dillon, Aoife A Maguire, Enda W McDermott et al

Selection of patients for breast-conserving surgery relies on inexact parameters such as the preoperative estimation of lesion size. This study investigates the value of needle core biopsy findings, in particular, the relative quantity of DCIS, in improving patient selection for breast conservation. Patients undergoing breast-conserving surgery for invasive ductal carcinoma from 1999 to 2004 were identified. Only patients who had a preoperative diagnosis of carcinoma (DCIS and invasive) on core biopsy were included. All core biopsies were reviewed by a breast histopathologist to document the quantity and characteristics of the DCIS component. Of a total of 281 patients, 46% (n=129) had invasive disease on core biopsy (group 1) and 54% (n=152) had either invasive disease with an accompanying DCIS component or DCIS only on core biopsy (group 2). The compromised margin rate for group 1 was 23% compared to 39% for group 2 (P=0.004). The rate of compromised margins increased progressively as the core biopsy DCIS component increased until a rate of 75% (n=18/24) was reached in patients with DCIS only on core biopsy. In patients with a DCIS component on core biopsy, the presence of necrosis (P=0.002), solid type architecture (P=0.008), high grade DCIS (P=0.007), calcification (P=0.003), and the relative proportion of DCIS present (P<0.001) were associated with compromised margins on univariate analysis. On multivariate analysis of this subgroup, the proportion of DCIS in this subgroup (P=0.048) was an independent predictor of compromised margins. The presence and relative proportion of DCIS on core biopsy provides important information as to whether patients are at risk of compromised margins. Documentation of these parameters may assist patient selection for breast-conserving surgery or identify patients who may benefit from wider margins at the time of initial operation.

Modern Pathology advance online publication 19 October 2007