November 2007
ANATOMIC PATHOLOGY
Histopathological Characteristics of Metastasizing Squamous Cell
Carcinoma of the Skin and Lips
P J F
Quaedvlieg, D H K V Creytens, G G Epping et al
Aims: The reported incidence of metastasis from squamous cell carcinoma (SCC) of the skin and lip varies between 0.5% and 16%. Clinical and histopathological criteria have been proposed to identify tumours that may have an increased risk of metastasis. The aim of this study was to define such high-risk tumours, especially since the incidence of SCC of the skin is increasing.
Methods
and results: Histopathological features of metastasized skin and lip
tumours and a matched group of non-metastasizing tumours were reassessed.
Characteristics studied were: tumour width, excision margins, histological
subtype,
Conclusions: A typical metastatic SCC showed: a tumour width of at least 15 mm, a vertical tumour thickness (= Breslow) of at least 2 mm, less differentiation, presence of desmoplasia and an inflammatory response with eosinophils and plasma cells.
Histopathology, Volume 49 Issue 3 Page 256-264, September 2006
Non-Operative Breast
Pathology
In
recent years, core needle biopsy has become an integral part of the triple
approach for the diagnosis of breast cancer lesions in screening programmes.
This technique has undoubtedly changed diagnostic breast pathology practice and
new diagnostic challenges have emerged. This issue of the Journal of Clinical Pathology contains a series of
reviews addressing troublesome areas of non-operative breast pathology,
including columnar cell change and flat epithelial atypia, lobular neoplasia,
apocrine change and hyperplasia, ductal hyperplastic and neoplastic lesions,
and metastasis to the breast, written by diagnostic breast pathologists based
in the
With the advent of the National Health Service Breast Screening Programme (NHS BSP) in the late 1980s, the ethos of obtaining a preoperative (or non-operative) diagnosis of breast abnormalities became firmly established and subsequently has been applied to both symptomatic and screening practice; frozen section diagnosis as a routine for breast lesions is a largely historical technique in the UK. The highest levels of accuracy in breast non-operative diagnosis are achieved using the triple approach, combining imaging and clinical examination assessment with pathological results; it is worth emphasising that fine needle aspiration cytology (FNAC) and core biopsy diagnosis from impalpable lesions should not be interpreted in isolation, but it has been recognised for many decades that a combination of the three disciplines results in accuracy of over 99%. The non-operative identification of the nature of a lesion in the breast, by either FNAC or core biopsy, allows rapid diagnosis and subsequent discussion with the patient regarding treatment options, including the benefit of avoiding unnecessary surgery for benign lesions, unless requested. Conversely, surgery for malignant lesions can be planned, both clinically and logistically.
Historically FNAC was the more widely used non-operative technique, but the introduction of automated core biopsy techniques led rapidly to its extensive utilisation in both screening and symptomatic disease assessment. This was largely as a result of a recognition that the targets defined for the preoperative diagnosis of breast carcinomas defined by the NHS BSP were not being met in many breast units using FNAC alone, along with publications reporting very high sensitivity and specificity for core biopsy. Application of the NHS BSP targets allows evaluation of performance; these include a preferred target of >80% for absolute sensitivity, >90% for complete sensitivity, >85% full specificity positive predictive value and >99.5%, with a suspicious rate ideally <5%. Although some units continue to use FNAC with great success, many use core biopsy as the predominant non-operative biopsy technique; problem lesions and histological difficulties in breast core biopsy diagnosis will be addressed in the reviews published in this issue.
This is not a static area of clinical practice and methods for, and application of, non-operative diagnosis, continue to be investigated in the research setting and developed in clinical practise. Some breast units have access to wider gauge needles, such as 11 gauge or 8 gauge cores utilising a vacuum-assisted technique, which can be used to target lesions with ultrasound or stereotaxis. These are most frequently applied to the assessment of microcalcifications, especially those that are mammographically of low or moderate suspicion, with a consequent reduction in the diagnostic biopsy rate reported. Such larger gauge core guns have the advantage of providing more tissue from often histologically difficult lesions, many of which are more specifically addressed by other authors in this issue. Other applications for these vacuum-assisted methods (such as the Mammotome device) include the removal of benign lesions, such as fibroadenomas, some papillary lesions and sub-areolar ducts; this is increasingly being undertaken, with the advantage to the patient of avoiding a surgical procedure. Data suggest that this is well tolerated by patients, and has few and minor complications. A second surgical procedure is relatively rarely required, particularly if there is no evidence of epithelial atypia on a preceding 14 gauge core sample. If, however, a 14 gauge core biopsy shows epithelial atypia (such as atypical ductal hyperplasia or lobular in situ neoplasia), the risk of associated carcinoma is in the region of at least 40-50%; it would therefore seem sensible that such patients are advised to undergo a diagnostic surgical procedure rather than 11 or 8 gauge vacuum-assisted excision.
Recent publications, and ongoing research into preoperative evaluation, indicate that lymph nodes from patients with invasive breast carcinoma may be sampled by either core biopsy or FNAC, and in this way a proportion of those with nodal metastases from breast cancer can be identified preoperatively (thus avoiding a second surgical procedure in these individuals); indeed such core biopsy and FNAC specimens are increasingly being received in the routine setting in pathology laboratories.
Accurate histological interpretation and reporting of core biopsy samples (whether 14 gauge, 11 gauge or 8 gauge), requires knowledge of the clinical and mammographic findings. It is, for example, essential to know whether one is searching for microcalcification within a core biopsy or an explanation for a breast mass. Receipt of a fully completed request form is essential; reporting samples in isolation of patient and clinical information is imprudent. Information should include full clinical details, radiological findings and the site of biopsy. Information on the date at which the case will be discussed at the multidisciplinary meeting is also helpful. In addition to details of the radiological findings, biopsy specimens taken for microcalcification should be x rayed and the cores sent with a specimen x ray; any radiological comment regarding the presence of representative microcalcification in the sample is valuable. It may be helpful for those cores which contain the microcalcification to be separately identified (in a separate pot, capsule or marked with dye); in this way laboratory and histological resources can be targeted on the appropriate portions of the sample.
As for all other breast samples, good fixation is essential for core biopsy specimens. This is, however, not in general a significant problem; the specimens should be placed quickly in sufficient fixative and sent to the laboratory. Ideally, biopsy specimens should be fixed routinely for a minimum of 6 h in order to optimally assess hormone receptor status and morphology, although it has been recognised for a long time that samples can be fixed more quickly with the aid of heat or microwave techniques. This can be performed if a particularly urgent result is required. More recently rapid processing techniques, when applied to breast cores, have been reported to produce good results for both H&E and immunohistochemical examination, although this is, as yet, not globally accepted or very widely used.
With regard to fixation, there are, conversely, reports of loss of microcalcification from specimens left in formalin or other aqueous solution for periods of time, and there is some data to suggest that this may occur relatively quickly, for example within 3 days; this could be a potential difficulty for specimens that remain in fixative over a weekend without processing. If, however, microcalcification is not readily visible, it is important to remember to search for calcium oxalate crystals, which may not be seen on H&E sections but are a common cause of mammographic microcalcification, and can be readily seen with polarised light. For larger breast specimens, high quality processing, section cutting and staining is essential. In some laboratories, a single level is examined for mass lesions, while cores from microcalcifications are assessed with a minimum of three levels stained with H&E. In practice, many laboratories choose to examine all core biopsy specimens from breast lesions with at least three levels initially, particularly those derived from screen-detected abnormalities; such issues will clearly differ between laboratories according to local preference and resources. It is helpful in such cases to retain the material between those levels examined with H&E, ideally on coated slides, in order to undertake immunohistochemistry, if required.
Although the inexperienced may imagine that all lesions can be specifically diagnosed on core biopsy specimens, particularly larger 11 gauge or 8 gauge samples, it must be noted that the main aim of histological examination of breast core biopsy specimens in the NHS BSP is to fulfill the assessment process and apply pathology categorisation (B1–B5) as part of the triple assessment process. Thus the primary aim within the NHS BSP is not to give a definitive diagnosis although, fortunately, this is possible in the vast majority of cases. Although most core biopsy specimens can be classified as normal (B1), benign (B2), or malignant (B5), a small proportion cannot. These lesions fall in the borderline categories of B3 (lesion of uncertain malignant potential) or B4 (suspicious). These borderline categories are most often applied to screen-detected abnormalities which are also frequently the more difficult lesions to classify on surgical excision specimens when abundant material is submitted for assessment; it should be no surprise that these lesions in small core biopsy specimens cannot be unequivocally categorised.
It must also be noted that the reporting categories for breast cores apply purely to the histological appearances within the specimen, and the choice of diagnostic category should be based solely on the features present in the sample, and not altered by the clinical or imaging characteristics. Clearly this pathology interpretation should be discussed in collaboration with the multidisciplinary team meeting and it is only in this setting that judgement can be made as to whether the sample is (i) adequate and (ii) representative of the mammographic lesion.
Within the B3 group of lesions of uncertain malignant potential are a variety of lesions that are either known to be heterogeneous (e.g., phyllodes tumours) or to be associated with a malignant lesion more often than one would expect by chance. Although the term risk of malignancy is used, it should be noted that this does not reflect increased risk in the future (in either the ipsilateral or contralateral breast), as most commonly applied. Indeed, although some of the lesions are associated both with future bilateral risk in an individual patient and with risk of there being adjacent malignancy at the time of biopsy, for example, atypical ductal hyperplasia, some are not generally recognised to be associated with significant future bilateral risk of developing breast carcinoma when there is no associated epithelial proliferative disease, for example, radial scar.
Also within the B3 category are included lesions showing epithelial atypia and thus raising a low suspicion of being derived from malignancy. Higher suspicion lesions should be categorised as B4 (suspicious). Even within these two categories, therefore, there is a grey area, particularly for epithelial intraductal proliferations regarding correct classification as either B3 or B4, although fortunately this is not generally clinically highly important and such lesions typically require more tissue for assessment, either in the form of repeat core biopsy (often with a wider bore needle, e.g. 11 gauge) or diagnostic surgical excision.
These borderline lesions are the topic of articles from various authors in this issue. These are derived from a sub-group of lectures from the NHS BSP Breast Pathology Update Course on Non-operative Diagnosis, Spring 2006. A portion of this course addressed borderline and/or difficult lesions in breast core biopsy and some of those individuals who gave presentations on the course have provided the reviews presented in this issue. These are areas that either currently cause diagnostic difficulties or have been the subject of recent reviews, updates or controversy.
Journal of Clinical Pathology, Volume
60(12), December 2007, pp 1297-1299
'Insignificant' Prostate Cancer on Biopsy: Pathologic Results from
Subsequent Radical Prostatectomy
P
A
'Insignificant' prostate cancer is defined as disease of virulence insufficient to threaten survival. In this review, which describes nine articles and two abstracts discussing almost 800 cases, we discuss the correlation of such 'insignificant' biopsy findings in the context of subsequent radical prostatectomy data. From our review, minimal disease on biopsy does not reliably predict minimal disease in the subsequent prostatectomy specimen, in terms of the size and grade of tumor, extracapsular extension or positive margins. Thus, reasoned accounting should be made of other data before undertaking a course of radiation therapy as monotherapy, particularly prostate-specific antigen kinetics and potential molecular markers.
Much attention has been paid in the urologic literature to the concept of 'insignificant' prostate cancer (CaP). Beginning with Epstein et al.'s first description in 1994, there have been over a dozen studies of the subject. The construct was originally intended to describe cancers that 'pose no threat to the patient and might be followed up without immediate treatment'. Although much data have been analyzed, it has almost exclusively been in radical prostatectomy (RP) specimens. Crucially, the concept of 'insignificant' CaP is thus best applied to patients after they have had definitive surgery of the lesion. What obviously is necessary is a metric that allows such classification based on biopsy criteria, before RP. This has proven elusive.
There have been far fewer studies of 'insignificance' in terms of biopsy data alone. These are the circumstances when decisions are made by physicians and patients with respect to therapy – specifically low risk therapy in many cases. If the construct of 'insignificance' on biopsy is not borne out on subsequent histopathologic examination, then low-risk therapy is less appropriate an option.
These data are critically important not only because they may potentially define a cadre of men for whom definitive therapy may be, or should not be, delayed, but also because they define a potential therapeutic bias that could impact on outcomes after therapies designed for low-risk disease. This construct is paradoxically less crucial when patients are treated with active surveillance than with interventions such as cryotherapy or radiation therapy as monotherapy. Under active surveillance, intervention is deferred pending more information. However, if patients with 'insignificant' biopsy findings but significant disease are treated with therapy commensurate with presumed low risk, results will be inappropriately poor because of this understaging of disease. This report surveys the literature on RP correlates of 'insignificant' CaP on biopsy, and describes other data currently available for the decision-making process before treating such patients as low-risk.
Prostate
Cancer Prostatic Dis., 2007;10(3):237-241.
Small and Microscopically Detected Gastrointestinal Stromal Tumours:
An Overview
Chetty R.
Small or microscopic gastrointestinal stromal
tumours (GISTs) have been the focus of recent publications. These lesions may
accompany clinically overt GISTs or be found incidentally in resection
specimens for gastro-oesophageal malignancies. While the majority of cases
consist of single lesions, approximately 30% may be multiple (usually two or
three such lesions). Several appellations have been employed to describe these
small GISTs: minute GISTs, GIST tumourlets, interstitial cell of Cajal (ICC)
hyperplasia, microscopic GISTs, minimal GISTs, and sclerosing stromal
tumourlets. As such, there has been no uniformity in terms of the size of these
small or microscopic lesions with tumours as small as 0.2 mm and those up to 10
mm, all falling within the remit of microscopic or minute GISTs. These lesions
have a predilection for the gastro-oesophageal junction and occur slightly more
frequently in the proximal stomach. They are typified by spindle-shaped cells
set within a hyalinised stroma which also shows calcification. Even the
smallest lesion has been shown to harbour mutations of the c-kit gene. They are
biologically indolent, and the majority of lesions appear to remain small
and/or show evidence of involution. However, it is possible that some are the
precursors of clinically significant GISTs.
Pathology, 2008
Feb;40(1):9-12.
Lymph Node Preparation in Resected Colorectal Carcinoma Specimens
Employing the Acetone Clearing Method
Vogel C, Kirtil T, Oellig F, Stolte M.
For the histopathological evaluation of resected
colorectal carcinoma specimens, the currently required minimum number of lymph
nodes that need to be examined to ensure accurate staging is 12. In some cases,
however, this number of lymph nodes cannot be obtained by the conventional
preparation method, based on formalin-fixed fatty tissue. Since prognostic
accuracy correlates with the number of lymph nodes examined, a repeat work-up
of the fatty tissue after soaking in acetone for 24h is a means of achieving
the required minimum of 12 lymph nodes in many cases. Our department, which
deals with an average of 307 colorectal cancer resection specimens per year,
received between May 2004 and November 2006 80 cases (10.4%) in which the
number of detected lymph nodes was less than 12. Owing to the use of
conventional preparation methods, the required number of 12 lymph nodes could
not be found, and subsequent acetone clearance of fatty tissue for a repeat
examination was carried out. On average, 4.4 additional lymph nodes having an
average size of 2mm were discovered. Accessory lymph node metastases were found
in 9 cases. In 2 of these, the UICC classification had to be revised. In 1
case, a lymph node metastasis was detected after acetone clearance in an
initially nodal negative carcinoma. Acetone clearance is an appropriate option
to identify accessory lymph nodes in colorectal carcinoma specimens for daily
routine use, and also constitutes an excellent instrument for internal quality
control.
Pathol Res Pract., 2007 Nov
14 [Epub ahead of print]
CLINICAL PATHOLOGY
Study Suggests Adjusting PSA Scores for Obese Men or Cancers May be
Missed
Doctors may be missing cancers in
obese men because the telltale blood marker used to detect the disease can be
falsely interpreted as low in this population, according to a new study led by
"Obese men have more blood circulating throughout their bodies than normal weight men, and as a result, the concentration of prostate-specific antigen, or PSA, in the blood -- the gold standard for detecting prostate cancer -- can become diluted," said Stephen Freedland, M.D., a Duke urologist and senior researcher.
"We've known for a while that obese men tend to have lower PSA scores than normal weight men, but our study really proposes a reason why this happens, and points to the need for an adjustment in the way we interpret PSA scores that will take body weight into account. If not, we may be missing a large number of cancers each year."
The study was funded by the Department of Veterans Affairs, the Duke Department of Surgery and Division of Urology, the Department of Defense Prostate Cancer Research Program, the American Urological Association Foundation, the Georgia Cancer Coalition, and the National Institutes of Health.
Researchers compared the medical records of almost 14,000 patients who had undergone radical prostatectomy surgery for the treatment of prostate cancer between 1988 and 2006 at Johns Hopkins, Duke, or at one of five Veterans Affairs hospitals making up the Shared Equal Access Regional Cancer Hospital (SEARCH) cohort. They analysed the relationship between body mass index -- which is a measure of obesity -- and PSA concentration levels, while also examining the blood volume in the patients' bodies and the total amount of PSA protein found in the blood, known as PSA mass, Freedland said.
"We found that a higher body mass index directly
correlated with higher blood volume and lower PSA concentrations," said
Lionel Bañez, M.D., a prostate cancer researcher in the
In this study, PSA mass across all groups was comparable despite differences in body weight, leading the researchers to believe that the larger blood volume is responsible for lowering the concentration of PSA, which is what doctors typically measure when looking for prostate cancer, Freedland said.
"It's as if you dissolve a tablet in a cup of water versus a tub of water," he said. "The concentration of the drug in the cup will be much higher than that in the tub, even though the amount is the same."
These findings are very important because of the sheer number of people they affect, Freedland said.
Clinical Laboratory International, 31,
N0.6, 25/11/2007
Evaluation of the Sysmex UF-100 Urine Cell Analyzer as a Screening
Test to Reduce the Need for Urine Cultures for Community-Acquired Urinary Tract
Infection
Kim SY, Kim YJ, Lee SM et al
Authors evaluated the UF-100 flow cytometer (TOA
Medical Electronics, Kobe , Japan
Am J Clin Pathol. 2007
Dec;128(6):922-5.
Fecal Immunochemical Test (FIT) for Colorectal Cancer Screening
Each year, 146,000 new cases of
colorectal cancer (CRC) are diagnosed in the
Screening tests for fecal occult blood have been
shown to significantly reduce CRC mortality.
The guaiac method has been used for many years, but it requires a three to five
day abstention from aspirin, NSAIDS, red meat, poultry, fish, certain
vegetables, and vitamin C. The guaiac method also detects blood of upper GI
origin, which is usually due to gastric inflammatory disease, rather than CRC.
The new Fecal Immunochemical Test (FIT) for occult blood has solved many of these problems. This method is highly specific for the globin portion of human hemoglobin and is easy for patients to use. It requires no dietary or medication restrictions, and it does not detect blood of upper GI origin. This means better patient compliance and fewer false-positive tests due to gastric inflammation or medications.
BOTTOM LINE
21st-Century Diagnostics: Recent Innovations in the Clinical
Laboratory
Clinical diagnostic laboratories are poised for a revolution. Recently developed screening technologies offer the promise of high-content, high-throughput molecular diagnostics, and are already now significantly increasing the amount of information that can quickly be obtained from patient samples. Three areas of innovation have emerged that are the primary drivers of this trend: genomics, proteomics, and microfluidics.
Recent technological
progress
Perhaps the most significant development in clinical diagnostics in the past five years has been the evolution of genomic and proteomic technologies for the systematic molecular analysis of clinical samples. In the area of genomics, both microarrays and qRT-PCR have provided molecular diagnostic laboratories with a new level of information-gathering capacity – to the extent that the primary challenge is now the effective management, standardisation, and interrogation of the sizable datasets generated by these methods. Powerful proteomics techniques such as protein microarrays are a more recent development, but may have an even greater potential to accurately diagnose disease at the molecular level. Complementary to the innovations in these two areas is a third trend with increasing relevance for clinical diagnostics – microfluidics. A constant stream of technological breakthroughs has given rise to a new generation of microfluidic devices that may well transform the practice of clinical diagnostics, giving healthcare providers a much greater ability to perform a plethora of advanced molecular diagnostics procedures at the point of care.
PCR and DNA microarrays
Although both technologies have
been available since the 1990s, their routine application in diagnostic
laboratories is more recent. Microarrays are now a standard option for many
molecular diagnostic laboratories, leaving analysts with the challenge of
sorting through and reliably comparing large amounts of quantitative data.
Real-time, quantitative RT-PCR has witnessed an important maturation in terms
of reproducibility, with numerous manufacturers now offering robust devices and
protocols suitable for high-thoughput environments. Novel technologies such as
immuno-PCR combine the signal amplification capacity of PCR with standard
antigen detection by antibodies, creating a synergistic diagnostic method
offering up to 10,000-fold higher sensitivity than ELISAs. The recent emergence
of array-based tools for cytogenetic and genomic analysis, provide advantages
over standard cytogenetic methods such as karyotyping and FISH. These include:
(1) a much higher degree of resolution; (2) the need for only small amounts of
genomic DNA as input material, as opposed to living cells; and (3) the
suitability for a high degree of automation, ideal for increasing throughput.
The need for biomarkers
Although these and other genomic
techniques are capable of providing valuable insight in terms of accurately
diagnosing patients at the molecular level, more information is needed. Data
regarding DNA sequence varations and RNA transcript levels of cell and tissues
can only provide a partial picture. What will complete this picture in many
cases is proteomics. In order to enable an earlier detection and correct
diagnosis of complex diseases and an improved risk stratification of patients,
novel biomarkers with high sensitivity and specificity are key. A rich source
for such biomarkers is the low molecular weight (LMW) range of the circulatory
proteome. Recent advancements in mass spectroscopy (MS) have already provided
analysts with the ability to rapidly obtain high-resolution portraits of the
LMW proteome, and new nanotechnologies for the collection and amplification of
LMW biomarkers will further improve the prognostic capacity of these
proteomics-based
diagnostic platforms.
Antibody availability is
key
An important development that has greatly facilitated this application of proteomics to clinical diagnostics has been the increasing availability of high-quality antibodies. Because of the unavailability of any direct methods for protein amplication, sensitivity is key in determining the utility of an antibody, and should ideally be in the near femtomolar range. An additional requirement is that of a linear and reproducible labelling and signal amplification protocol. To illustrate the importance of antibody sensitivity, consider that a needle biopsy or cell aspirate may consist of fewer than 100,000 cells, and that in the case of a heterogenous cell population, the number of antigen-expressing cells may only be a few thousand. If the target proteins and/or their phosphorylated versions are only present in low abundance, then the final concentration of these molecules in the sample is therefore very low indeed.
Highly senstive protein microarrays are now available, enabling, for the first time, a comprehensive query of proteome activity in clinical specimens. Nonetheless, the effective integration of protein microarrays and similarly innovative proteomics technologies into clinical molecular diagnostic laboratories will depend on both the speed of additional methodological developments, and the implementation of stringent standardisation and quality control measures.
Size matters
Although proteomics methods will
undoubtably soon benefit from going small, genomics is currently the primary
target for newly emerging microfluids technologies. To increase the throughput of
genomic analytical techniques in clinical diagnostics laboratories, the speed
and efficiency of electric field-mediated separations will need further
continuation in improvement. The size-dependent fractionation of reaction
products is currently the primary rate-limiting step for many genomic tests,
often requiring hands-on intervention by laboratory personnel. Over the past
several years, microfabricated chips have emerged as a powerful alternative to
standard electrophoresis devices, and promise to radically alter the way in
which many molecular assays are carried out.
Applications for microfluidics
Diagnostic procedures that stand
to benefit most from microfluidics include those genotyping protocols involving
DNA sequencing, restriction fragment analysis, allele-specific amplification,
hybridisation methods and hetroduplex analysis. In addition to the acceleration
in analytical speed, microchip electrophoresis systems have the advantage of
low sample volume as well as excellent multiplexing ability. A further benefit
of these microdevices is that of good system integration capacity, referring to
the seamless linkage of various procedures such as sample preparation and
purification, sample modification and manipulation (e.g., PCR amplification or
restriction digestion), and sample analysis (e.g. separation or fractionation).
With the emergence of a competitive industry offering various
microfluidics-based analytical platforms based on disposable plastic chips, the
already favourable cost of performing “microdiagnostics” will, in all
likelihood, continue to improve.
In short, the confluence of numerous recent innovations in genomics, proteomics
and microfluidics is already impacting clinical diagnostics in a noticable
fashion. Further development and integration of these new technologies will
give rise to powerful new molecular diagnostics platforms benefitting both
healthcare providers and patients in the years to come.
Clinical Laboratory International, Vol. 31,
Issue 5, September 2007