Temporal Artery Biopsy Specimens Research Articles

Consensus statement on the processing, interpretation and reporting of temporal artery biopsy for arteritis

Giant cell arteritis (GCA) is the most common systemic vasculitis in adults in Europe and North America, typically involving the extra-cranial branches of the carotid arteries and the thoracic aorta. Despite advances in noninvasive imaging, temporal artery biopsy (TAB) remains the gold standard for establishing a GCA diagnosis. The processing of TAB depends largely on individual institutional protocol, and the interpretation and reporting practices vary among pathologists. To address this lack of uniformity, the Society for Cardiovascular Pathology formed a committee tasked with establishing consensus guidelines for the processing, interpretation, and reporting of TAB specimens, based on the existing literature. This consensus statement includes a discussion of the differential diagnoses including other forms of arteritis and noninflammatory changes of the temporal artery.

Histopathology reporting of temporal artery biopsy specimens for giant cell arteritis: results of a modified Delphi study

The temporal artery biopsy (TAB) is regarded as the gold-standard test in the diagnosis of giant cell arteritis (GCA). There is a lack of agreement among experienced pathologists regarding the...

Ultrasound centre frequency shifts as a novel approach for diagnosing giant cell arteritis

Objective Giant cell arteritis (GCA) is a treatable, but potentially sight- and life-threatening form of systemic vasculitis. Prompt and correct diagnosis is therefore important. Temporal artery biopsy (TAB) is the gold standard for diagnosing GCA, but is associated with risks. There is no reliable non-invasive technique for the diagnosis of GCA. Ultrasound centre frequency shift (CFS) is a novel technique that uses high-frequency ultrasound and the analysis of the centre frequency of the ultrasound pulse, which is dependent on the size of the microstructures in the tissue. This provides an objective measure of the scattering microstructures in the tissue, and thus has the potential to discriminate changes due to disease. The aim of this study was to assess ultrasound CFS as a means of discriminating arteries affected by GCA from healthy arteries. Method TAB specimens from 68 subjects, 53 female and 15 male, with a mean age of 73 (range 52–87) years, with suspected GCA were examined using ultrasound ex vivo and the CFS was analysed. The temporal arteries were then examined histopathologically. Results Histopathological examination revealed that 25 of the 68 biopsies of the temporal artery showed inflammatory changes in the vessel wall compatible with GCA. The ultrasound CFS decreased less in TAB-positive than in TAB-negative temporal arteries (p < 0.05). Conclusions This proof-of-principle study indicates that ultrasound CFS has the potential to detect GCA in temporal arteries. Further technical development will be needed before in vivo examination can be performed and the clinical applicability can be assessed.

Clinicopathologic Associations in a Large International Cohort of Patients With Giant Cell Arteritis

In addition to aiding in diagnosis, histopathologic findings from temporal artery biopsy (TAB) specimens in giant cell arteritis (GCA) may be valuable for their associations with clinical features of the disease. This study was undertaken to compare histopathologic findings on TAB with biopsy interpretation and demographic, clinical, and imaging features at time of diagnosis. Patients with a clinical diagnosis of GCA who had a TAB were selected from an international, multicenter observational cohort of vasculitis. Associations between demographic, clinical, radiographic, and histopathologic features were identified using bivariate testing and multivariate regression modeling. Of 705 patients with GCA who underwent TAB, 69% had histopathologic evidence of definite vasculitis. Specific histopathologic findings included the presence of giant cells (51%), fragmentation of the internal elastic lamina (41%), intimal thickening (33%), and predominantly mononuclear leukocyte infiltration (32%). Histopathologic interpretation of definite vasculitis was independently associated with giant cells (odds ratio [OR] 151.8 [95% confidence interval (95% CI) 60.2-551.6]), predominantly mononuclear leukocyte infiltration (OR 11.8 [95% CI 5.9-24.9]), and fragmentation of the internal elastic lamina (OR 3.7 [95% CI 1.9-7.4]). A halo sign on temporal artery ultrasound and luminal damage of large arteries on angiography were significantly associated with presence of giant cells (OR 2.6 [95% CI 1.1-6.5] and OR 2.4 [95% CI 1.1-5.2], respectively). Specific histopathologic findings were associated with older age, but no associations were identified with vision loss or other clinical features. Histopathologic findings in GCA are strongly associated with the clinical diagnosis of GCA but have a limited role in identifying patterns of disease.

Effect of Temporal Artery Biopsy Length and Laterality on Diagnostic Yield.

Giant cell arteritis (GCA) is the most common vasculitis in adults and is associated with significant morbidity and mortality. Temporal artery biopsy (TAB) remains the gold standard for diagnosis in the United States; however, practices vary in the length of artery obtained and whether bilateral simultaneous biopsies are obtained. Retrospective chart review of all TABs performed at the Johns Hopkins Wilmer Eye Institute between July 1, 2007, and September 30, 2017. Five hundred eighty-six patients underwent TAB to evaluate for GCA. Of 404 unilateral biopsies, 68 (16.8%) were positive. Of 182 patients with bilateral biopsies, 25 (13.7%) had biopsies that were positive and 5 patients (2.7%) had biopsies that were discordant, meaning only 1 side was positive. There was no significant difference in the average postfixation length of positive and negative TAB specimens (positive mean length 1.38 ± 0.61 cm, negative mean length 1.39 ± 0.62 cm, P = 0.9). There is no significant association between greater length of biopsy and a positive TAB result in our data. Although the rate of positive results was not higher in the bilateral group compared with the unilateral group, 2.7% of bilateral biopsies were discordant, similar to previously published rates. Overall, this suggests that initial bilateral biopsy may increase diagnostic yield, albeit by a small amount.

A Distinct Macrophage Subset Mediating Tissue Destruction and Neovascularization in Giant Cell Arteritis: Implication of the YKL‐40/Interleukin‐13 Receptor α2 Axis

ObjectiveMacrophages mediate inflammation, angiogenesis, and tissue destruction in giant cell arteritis (GCA). Serum levels of the macrophage‐associated protein YKL‐40 (chitinase 3–like protein 1), previously linked to angiogenesis and tissue remodeling, remain elevated in GCA despite glucocorticoid treatment. This study was undertaken to investigate the contribution of YKL‐40 to vasculopathy in GCA.MethodsImmunohistochemistry was performed on GCA temporal artery biopsy specimens (n = 12) and aortas (n = 10) for detection of YKL‐40, its receptor interleukin‐13 receptor α2 (IL‐13Rα2), macrophage markers PU.1 and CD206, and the tissue‐destructive protein matrix metalloproteinase 9 (MMP‐9). Ten noninflamed temporal artery biopsy specimens served as controls. In vitro experiments with granulocyte–macrophage colony‐stimulating factor (GM‐CSF)– or macrophage colony‐stimulating factor (M‐CSF)–skewed monocyte‐derived macrophages were conducted to study the dynamics of YKL‐40 production. Next, small interfering RNA–mediated knockdown of YKL‐40 in GM‐CSF–skewed macrophages was performed to study its effect on MMP‐9 production. Finally, the angiogenic potential of YKL‐40 was investigated by tube formation experiments using human microvascular endothelial cells (HMVECs).ResultsYKL‐40 was abundantly expressed by a CD206+MMP‐9+ macrophage subset in inflamed temporal arteries and aortas. GM‐CSF–skewed macrophages from GCA patients, but not healthy controls, released significantly higher levels of YKL‐40 compared to M‐CSF–skewed macrophages (P = 0.039). In inflamed temporal arteries, IL‐13Rα2 was expressed by macrophages and endothelial cells. Functionally, knockdown of YKL‐40 led to a 10–50% reduction in MMP‐9 production by macrophages, whereas exposure of HMVECS to YKL‐40 led to significantly increased tube formation.ConclusionIn GCA, a GM‐CSF–skewed, CD206+MMP‐9+ macrophage subset expresses high levels of YKL‐40 which may stimulate tissue destruction and angiogenesis through IL‐13Rα2 signaling. Targeting YKL‐40 or GM‐CSF may inhibit macrophages that are currently insufficiently suppressed by glucocorticoids.

Mönckeberg sclerosis with giant cells as a masquerade of giant cell arteritis.

Giant cell arteritis (GCA) is the most common type of vasculitis in adults, which is classified as a large/medium vessel vasculitis. It has a predilection for the ophthalmic circulation and extracranial carotid system. Temporal artery biopsy specimens can show the presence of inflammatory multinucleated giant cells. Here, we report just the third case of Mönckeberg sclerosis with multinucleated giant cells affecting the temporal artery and mimicking GCA. This rare finding in the evaluation of a common vasculitis is important for rheumatologists to be aware of and emphasizes close collaboration between clinicians and pathologists.

Association Between Specimen Length and Number of Sections and Diagnostic Yield of Temporal Artery Biopsy for Giant Cell Arteritis.

To investigate the association between specimen length and number of sections evaluated and the diagnostic yield of temporal artery biopsy (TAB) for giant cell arteritis (GCA). A pathologist reviewed all TABs performed for suspected GCA between January 1991 and December 2012. The blocks of all the inadequate and negative biopsy specimens were recut, and further slides at deeper levels were stained with hematoxylin and eosin in order to avoid missing inflammatory changes. In total, findings from 662 TABs were included in the study (71% female; mean age 73.2 years). A total of 427 TAB specimens (65%) were classified as negative, and 235 (35%) were classified as positive for GCA. Compared to those with negative TAB results, patients with positive TAB results were older and more frequently female. There was no difference in postfixation TAB specimen length between TAB specimens negative and positive for GCA (mean 6.5 mm versus 6.9 mm; P = 0.068). Cuts of additional biopsy sections revealed inflammation at deeper levels in 26 of 408 TAB specimens (6.4%) originally reported as uninflamed. The inflamed section was the second in 14 TAB specimens, the third in 9 specimens, and the fourth in 3 specimens. Piecewise logistic regression identified 5 mm as the TAB specimen length change point for diagnostic sensitivity. Compared to a TAB specimen length of <5 mm, the age- and sex-adjusted odds ratio for positive TAB results in samples ≥5 mm long was 1.5 (95% confidence interval 1.0-2.0), P = 0.032. A postfixation TAB specimen length of at least 5 mm should be sufficient to make a histologic diagnosis of GCA. In order not to miss inflammatory changes, at least 3 further sections at deeper levels should be evaluated in all negative TAB specimens.

Peripheral retinal arteriolar leakage in giant cell arteritis: a case report

A 76-year old African American female with a history of arteritic ischemic optic neuropathy (AION) secondary to biopsy-proven giant cell arteritis (GCA) presented with unilateral vision loss in her contralateral eye despite high-dose oral steroid treatment. Dilated fundus examination revealed three cotton wool spots. Fluorescein angiography showed slowed arteriolar filling with late staining of small peripheral arteries, consistent with small vessel arteritis. Laboratory tests for alternative vasculitides were negative. Review of her temporal artery biopsy specimen confirmed lymphoplasmacytic inflammation around small adventitial vessels with no destructive granulomatous or leukocytoclastic small vessel vasculitis, consistent with GCA. Our unique case demonstrates peripheral small vessel retinal arteriolar leakage in GCA, which is a rare finding. This association is of interest because GCA is commonly associated with medium to large vessel pathology without small vessel involvement.

Temporal Arteritis Revealing Antineutrophil Cytoplasmic Antibody-Associated Vasculitides: A Case-Control Study.

Temporal arteritis (TA) is a typical manifestation of giant cell arteritis (GCA). Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAVs) are rarely revealed by TA manifestations, leading to a risk of misdiagnosis of GCA and inappropriate treatments. This study was undertaken to describe the clinical, biologic, and histologic presentations and outcomes in cases of TA revealing AAV (TA-AAV) compared to controls with classic GCA. In this retrospective case-control study, the characteristics of patients with TA-AAV were compared to those of control subjects with classic GCA. Log-rank test, with hazard ratios (HRs) and 95% confidence intervals (95% CIs), was used to assess the risk of treatment failure. Fifty patients with TA-AAV (median age 70 years) were included. Thirty-three patients (66%) presented with atypical symptoms of GCA (ear, nose, and throat involvement in 32% of patients, and renal, pulmonary, and neurologic involvement in 26%, 20%, and 16% of patients, respectively). Blood samples were screened for ANCAs at the time of disease onset in 33 patients, and results were positive in 88%, leading to a diagnosis of early TA-AAV in 20 patients. The diagnosis of AAV was delayed a median interval of 15 months in 30 patients. Compared to controls with GCA, patients with TA-AAV were younger (median age 70 years versus 74 years), were more frequently men (48% versus 30%), and had high frequencies of atypical manifestations and higher C-reactive protein levels (median 10.8 mg/dl versus 7.0 mg/dl). In patients with TA-AAV, temporal artery biopsy (TAB) showed fibrinoid necrosis and small branch vasculitis in 23% of patients each, whereas neither of these characteristics was evident in controls with GCA. Treatment failure-free survival was comparable between early TA-AAV cases and GCA controls, whereas those with delayed TA-AAV had a significantly higher risk of treatment failure compared to controls (HR 3.85, 95% CI 1.97-7.51; P < 0.0001). TA-AAV should be considered diagnostically in cases of atypical manifestations of GCA, refractoriness to glucocorticoid treatment, or early relapse. Analysis of TAB specimens for the detection of small branch vasculitis and/or fibrinoid necrosis could be useful. Detection of ANCAs should be performed in cases of suspected GCA with atypical clinical features and/or evidence of temporal artery abnormalities on TAB.

Tissue-specific relaxin-2 is differentially associated with the presence/size of an arterial aneurysm and the severity of atherosclerotic disease in humans.

Circulating or tissue-related biomarkers are of clinical value for risk stratification in patients with abdominal aortic aneurysms. Relaxin-2 (RL2) has been linked to the presence and size of arterial aneurysms, and to the extent of atherosclerosis in human subjects. Here, we assessed the expression levels of RL2 in aneurysmal (AA, n = 16) and atherosclerotic (ATH, n = 22) arteries, and established the correlation between RL2 levels and the presence/size of AA and the clinical severity of atherosclerosis. The expression levels of metalloproteinases (MMPs) and endothelial nitric oxide synthetase (eNOS) were also detected for correlations with different phenotypes of atherosclerosis and AA. Temporal artery biopsy specimens (n = 6) and abdominal aortic tissues harvested from accident victims during autopsy (n = 10) were used as controls. Quantitative tissue biomarker analysis revealed that tissue-specific RL2 was increased in patients with larger or symptomatic AA compared to subjects with atherosclerotic disease and healthy controls. In situ RL2 levels were proportional to the size and the severity of aneurysmatic disease, and were substantially elevated in patients with symptomatic aneurysm of any diameter or asymptomatic aneurysm of a diameter >350% of that of the normal artery. In contrast, tissue RL2 was inversely associated with the clinical severity of atherosclerotic lesions. Correlation between RL2 and MMP2 was different between ATH1 and ATH2, depending on atherosclerosis grade. Overall, tissue RL2 is differentially associated with discrete phenotypes of arterial disease and might exert multipotent biological effects on vascular wall integrity and remodeling in human subjects.

Assessment for varicella zoster virus in patients newly suspected of having giant cell arteritis.

There is uncertainty if varicella zoster virus (VZV) triggers GCA. This is based on discordant reports of VZV detection in GCA temporal artery biopsies. We conducted a multimodal evaluation for VZV in the inception Giant Cell Arteritis and PET Scan (GAPS) cohort. Consecutive patients who underwent temporal artery biopsy for suspected GCA were clinically reviewed for active and past VZV infection and followed for 6 months. Serum was tested for VZV IgM and IgG. Temporal artery biopsy (TAB) sections were stained for VZV antigen using the VZV Mouse Cocktail Antibody (Cell Marque, Rocklin, CA, USA). A selection of GCA and control tissues were stained with the VZV gE antibody (Santa Cruz Biotechnology, Dallas, TX, USA), which was used in previous studies. A total of 58 patients met inclusion criteria, 12 (21%) had biopsy-positive GCA and 20 had clinically positive GCA. None had herpes zoster at enrolment and only one patient developed a VZV clinical syndrome (zoster ophthalmicus) on follow-up. There was no difference in VZV exposure between GCA and non-GCA patients. None of the 53 patients who had VZV serology collected had positive VZV IgM antibodies. VZV antigen was not convincingly demonstrated in any of the TAB specimens; 57 TABs stained negative and 1 stained equivocally positive. The Santa Cruz Biotechnology VZV antibody exhibited positive staining in a range of negative control tissues, questioning its specificity for VZV antigen. The absence of active infection markers argues against VZV reactivation being the trigger for GCA. Non-specific immunohistochemistry staining may account for positive findings in previous studies.

Resident Perspectives

Resident Perspectives

CD3 immunohistochemistry is helpful in the diagnosis of giant cell arteritis.

To evaluate whether CD3 staining performed routinely on temporal artery biopsy specimens might improve the sensitivity of temporal artery biopsy in patients with biopsy-negative GCA. Two hundred and seventy biopsies were considered for this study, stained with haematoxylin and eosin and with an anti-CD3 antibody. The addition of CD3 staining modified the sensibility and the specificity of the histologic examination in 89.47 and 95.00%, respectively, with a positive and negative predictive values of 97.00 and 79.78% . The addition of CD3 immunostaining to the classic histologic evaluation is accompanied by a significant increase in the sensibility with a comparable specificity.

Geo-epidemiology of temporal artery biopsy-positive giant cell arteritis in Australia and New Zealand: is there a seasonal influence?

ObjectivePrevious studies, although inconclusive, have suggested possible associations of environmental risk factors with the development of giant cell arteritis (GCA). We aim to investigate seasonal influence on the incidence of...

Association between specimen length and diagnostic yield of temporal artery biopsy

Objectives: Temporal artery biopsy (TAB) is performed in patients suspected of giant cell arteritis (GCA). Inadequate TAB specimen length is considered a possible explanation for a negative biopsy in patients with GCA. We investigated the association between specimen length and diagnostic yield of TAB.Method: We conducted a retrospective analysis of 240 patients who underwent TAB in a single hospital between 2000 and 2015. Patients were diagnosed with GCA based on positive TAB or, when TAB was negative, on clinical grounds that fulfilled the American College of Rheumatology (ACR) 1990 criteria. Baseline clinical and laboratory features and TAB length were obtained from medical records. Among patients diagnosed with GCA, the rate of TAB positivity was calculated according to biopsy length (< 5, 5–9, 10–14, and ≥ 20 mm).Results: Out of 240 patients, 88 were diagnosed with GCA: 62 had a positive TAB and 26 were diagnosed based on clinical grounds despite a negative TAB. Among those who were diagnosed with GCA, the length of the TAB specimen was similar in those with a positive and a negative TAB (1.13 ± 1.68 mm vs. 1.15 ± 0.61 mm, respectively, p = 0.928). The TAB positivity rate was similar among all ranges of biopsy length [< 5 mm: 7/10 (70%); 5–9 mm: 22/31 (71%); 10–14 mm: 11/16 (69%); 15–19 mm: 11/16 (69%); ≥ 20 mm: 11/15 (73%, p = ns] and was similar to the overall biopsy positivity rate.Conclusions: Specimen length is not associated with diagnostic yield of TAB.

Flares in Biopsy-Proven Giant Cell Arteritis in Northern Italy: Characteristics and Predictors in a Long-Term Follow-Up Study.

This study evaluated the frequency, timing, and characteristics of flares in a large cohort of Italian patients with biopsy-proven giant cell arteritis (GCA) and to identify factors at diagnosis able to predict the occurrence of flares. We evaluated 157 patients with biopsy-proven transmural GCA diagnosed and followed at the Rheumatology Unit of Reggio Emilia Hospital (Italy) for whom sufficient information was available from the time of diagnosis until at least 4 years of follow-up. Fifty-seven patients (36.5%) experienced ≥1 flares. Fifty-one (46.4%) of the 110 total flares (88 relapses and 22 recurrences) were experienced during the first 2 years after diagnosis. The majority of relapses occurred with doses of prednisone ≤ 10 mg/day (82.9%), whereas only 3.4% of relapses occurred for doses ≥ 25 mg/day. Polymyalgia rheumatica (46.5%) and cranial symptoms (41.9%) were the most frequent manifestations at the time of the first relapse. Cumulative prednisone dose during the first year and total cumulative prednisone dose were significantly higher in flaring patients compared with those without flares (7.8 ± 2.4 vs 6.7 ± 2.4 g, P = 0.02; 15.5 ± 8.9 vs 10.0 ± 9.2 g, P = 0.0001, respectively). The total duration of prednisone treatment was longer in flaring patients (58 ± 44 vs 30 ± 30 months, P = 0.0001).Patients with disease flares had at diagnosis more frequently systemic manifestations (P = 0.02) and fever ≥ 38°C (P = 0.02), significantly lower hemoglobin levels (P = 0.05), more frequent presence at temporal artery biopsy (TAB) specimens of giant cells (P = 0.04) and intraluminal acute thrombosis (P = 0.007), and more moderate/severe arterial inflammation (P = 0.009) compared with those without flares. In the multivariate model fever ≥ 38 °C (hazard ratio 2.14; 95% confidence interval, 1.06–4.32, P = 0.03) and the severity of inflammatory infiltrate (moderate/severe versus mild) (hazard ratio 5.41; 95% confidence interval, 1.64–17.87, P = 0.006) were significantly associated with an increased risk of flares. In conclusion, a flaring course is common in GCA and it is associated with prolonged GC requirements. Fever at diagnosis and severity of inflammation at TAB appear to predict the development of disease flares.

Correlation of clinical profile and specific histopathological features of temporal artery biopsies.

This study sought to correlate the clinical features of patients with giant cell arteritis (GCA) who present with ophthalmic symptoms and signs, with 2 specific histopathological findings-the presence of giant cells and arterial wall neoangiogenesis. The goal was to assess if these pathological features might be useful in guiding the approach to patient management. Medical charts were retrospectively reviewed from 58 patients who underwent a temporal artery biopsy at a single institution. Detailed information was collected about the clinical presentation and course, with an emphasis on visual function. Histopathological and immunohistochemical techniques were used to examine temporal artery biopsies for evidence of inflammation. Correlations were made between the clinical data and the presence of giant cells and neoangiogenesis. Twenty-one (34%) biopsies were positive for inflammation consistent with GCA. Although the percentage of positive biopsies with giant cells was high, neither the presence of giant cells nor neoangiogenesis was predictive of a patient's presenting visual symptoms, severity and bilaterality of vision loss, other ophthalmic manifestations of GCA, presence of headache or jaw claudication, or erythrocyte sedimentation rate. Giant cells were more common in patients with recent weight loss. Immunohistochemistry confirmed diagnoses but did not alter the clinical course or treatment plan. There was no correlation between the clinical, specifically visual, features of GCA and the presence or absence of giant cells or neoangiogenesis in temporal artery biopsy specimens. Although the presence of neoangiogenesis may be important in the pathogenesis of GCA, our study showed no correlation between this finding and the clinical course.

Temporal artery biopsies; do they make the cut?

Background and AimsTemporal artery biopsy is the gold standard investigation for giant cell arteritis. Guidelines recommend that specimens should measure no less than 1 cm and ideally more than 2 cm in length, as this influences the likelihood of biopsy positivity. This audit investigates the extent to which temporal artery biopsies acquired in our hospital meet these guidelines.MethodsHistopathology reports for all temporal artery biopsies performed at University Hospital Ayr between January 2011 and June 2013 were examined.ResultsFifty-six temporal artery biopsy specimens showed a range in length from 0.5 cm to 3.1 cm, with a mean of 1.4 cm. Thirty-seven biopsies measured ≥1 cm (66%) and 13 were ≥2 cm (23%). Therefore, 19 samples (34%) did not meet the recommended standard. Just seven biopsies showed features of giant cell arteritis, with six of these measuring ≥1 cm in length (86%).ConclusionThe guidelines for temporal artery specimens are not being met at our centre. Furthermore, biopsies measuring ≥1...

Temporal artery biopsies: do they make the cut?

Temporal artery biopsy is the gold standard investigation for giant cell arteritis. Guidelines recommend that specimens should measure no less than 1 cm and ideally more than 2 cm in length, as this influences the likelihood of biopsy positivity. This audit investigates the extent to which temporal artery biopsies acquired in our hospital meet these guidelines. Histopathology reports for all temporal artery biopsies performed at University Hospital Ayr between January 2011 and June 2013 were examined. Fifty-six temporal artery biopsy specimens showed a range in length from 0.5 cm to 3.1 cm, with a mean of 1.4 cm. Thirty-seven biopsies measured ≥1 cm (66%) and 13 were ≥2 cm (23%). Therefore, 19 samples (34%) did not meet the recommended standard. Just seven biopsies showed features of giant cell arteritis, with six of these measuring ≥1 cm in length (86%). The guidelines for temporal artery specimens are not being met at our centre. Furthermore, biopsies measuring ≥1 cm are much more common in the small group of positive results. This validates the minimum recommended biopsy length and displays the importance of achieving this standard. We suggest changes to increase the number of biopsies meeting these guidelines, improving the accuracy of this invasive test.