Precise Histopathological Diagnosis Research Articles

Validation of prostate and breast cancer detection artificial intelligence algorithms for accurate histopathological diagnosis and grading: a retrospective study with a Japanese cohort

Prostate and breast cancer incidence rates have been on the rise in Japan, emphasising the need for precise histopathological diagnosis to determine patient prognosis and guide treatment decisions. However, existing diagnostic methods face numerous challenges and are susceptible to inconsistencies between observers. To tackle these issues, artificial intelligence (AI) algorithms have been developed to aid in the diagnosis of prostate and breast cancer. This study focuses on validating the performance of two such algorithms, Galen Prostate and Galen Breast, in a Japanese cohort, with a particular focus on the grading accuracy and the ability to differentiate between invasive and non-invasive tumours. The research entailed a retrospective examination of 100 consecutive prostate and 100 consecutive breast biopsy cases obtained from a Japanese institution. Our findings demonstrated that the AI algorithms showed accurate cancer detection, with AUCs of 0.969 and 0.997 for the Galen Prostate and Galen Breast, respectively. The Galen Prostate was able to detect a higher Gleason score in four adenocarcinoma cases and detect a previously unreported cancer. The two algorithms successfully identified relevant pathological features, such as perineural invasions and lymphovascular invasions. Although further improvements are required to accurately differentiate rare cancer subtypes, these findings highlight the potential of these algorithms to enhance the precision and efficiency of prostate and breast cancer diagnosis in Japan. Furthermore, this validation paves the way for broader adoption of these algorithms as decision support tools within the Asian population.

Immunohistochemical expression of BCL-2 in hydatidiform moles: a tissue microarray study.

Hydatidiform moles (HM) are members of gestational trophoblastic diseases (GTD) and, in some cases, might progress to gestational trophoblastic neoplasia (GTN). HMs are either partial (PHM) or complete (CHM). Some HMs are challenging in arriving at a precise histopathological diagnosis. This study aims to investigate the expression of BCL-2 by immunohistochemistry (IHC) in HMs as well as in normal trophoblastic tissues "products of conception (POC) and placentas" using Tissue MicroArray (TMA) technique. TMAs were constructed using the archival material of 237 HMs (95 PHM and 142 CHM) and 202 control normal trophoblastic tissues; POC and unremarkable placentas. Sections were immunohistochemically stained using antibodies against BCL-2. The staining was assessed semi-quantatively (intensity and percentage of the positive cells) in different cellular components (trophoblasts and stromal cells). BCL-2 showed cytoplasmic expression in more than 95% of trophoblasts of PHM, CHM and controls. The staining showed a significant reduction of the intensity from controls (73.7%), PHMs (76.3%) to CHM (26.9%). There was a statistically significant difference between PHM and CHM in the intensity (p-value 0.0005) and the overall scores (p-value 0.0005), but not the percentage score (p-value > 0.05). No significant difference was observed in the positivity of the villous stromal cells between the different groups. All cellular components were visible using the TMA model of two spots/case (3 mm diameter, each) in more than 90% of cases. Decreased BCL-2 expression in CHM compared to PHM and normal trophoblasts indicates increased apoptosis and uncontrolled trophoblastic proliferation. Construction of TMA in duplicates using cores of 3 mm diameter can overcome tissue heterogeneity of complex lesions.

Synovial biopsy for establishing a definite diagnosis in undifferentiated chronic knee monoarthritis

BackgroundUndifferentiated arthritis is a condition in which the problem cannot be classified into any definite diagnosis category. Various methods have been suggested to clarify the definite diagnosis in this class. The synovial biopsy is suggested as the last diagnostic approach to determine the precise histopathological diagnosis. In this study, we aimed to evaluate the efficacy of synovial biopsy for establishing a definite diagnosis in patients with undifferentiated chronic knee monoarthritis.MethodsThe present retrospective case series was conducted in 2005 in the rheumatology research center of Shariati hospital and the 501 hospital in Tehran, Iran. The study included the synovial biopsy of patients with chronic knee monoarthritis who did not have a definite diagnosis after all the diagnostic steps before the synovial biopsy. Pathology slides of the patients’ synovial biopsy were reevaluated with a senior expert pathologist.ResultsEighty patients with a mean age of 37.6 ± 17.32 years (range: 6–68) were included, of whom 50% were female. The gap time between the onset of knee monoarthritis and the decision-making for synovial biopsy was 14.34 ± 19.61 months. Histopathologic evaluations revealed non-specific synovitis in 65% of the patients and a definite diagnosis in 35%. The most common definite diagnosis was rheumatoid arthritis (9%), followed by septic arthritis (5%). The most common pathologic findings were endothelial proliferation (89%) and synovial proliferation (88%), and the most common infiltrating cell was lymphocyte (54%). Patients with non-specific synovitis were more likely to have neovascularization, cellular infiltration (p-value < 0.001), synovial proliferation, endothelial proliferation (p-value = 0.001), pannus formation (p-value = 0.009), and fibrosis (p-value = 0.022) compared to the patients with a definite pathologic diagnosis. However, age, gender, and the gap time between disease symptoms to synovial biopsy were not significantly different between the different groups of diagnosis (p-value > 0.05).ConclusionNon-specific synovitis remains the most common histopathologic finding, highlighting the importance of physician expert opinion for most of the patients with undifferentiated chronic knee monoarthritis. Studies with larger samples and immunohistochemistry analyses are needed to clarify this uncategorized entity further.

P07.07.A Fluorescence lifetime imaging for improved visualization of 5-ALA fluorescence during biopsies of suspected brain tumors

Abstract Background Stereotactic brain tumor biopsies represent a standard neurosurgical technique enabling a precise histopathological tumor diagnosis which is of utmost importance for optimal further treatment allocation. However, non-diagnostic biopsies are not uncommon in routine clinical practice. To overcome this shortcoming, serial biopsies or intraoperative histopathology are typically performed prolonging the operating times and potentially increasing the risk of complications. Recently, the value of 5-aminolevulinic acid (5-ALA) induced protoporphyrin IX (PpIX) fluorescence for visualization of diagnostic tumor tissue was demonstrated in navigation-guided brain tumor biopsies. However, a not negligible proportion of brain tumors lack visible fluorescence. In some of these tumors, a subvisual concentration of PpIX could be detected by spectroscopic analysis. Thus, detection of such subvisual PpIX accumulation in tumor samples in biopsies by the new “Fluorescence Lifetime Imaging” (FLIM) technique might lead to further improvement of this approach. Material and Methods Patients that underwent navigation-guided biopsy of a suspected brain tumor were eligible for inclusion in this study. After administration of 5-ALA, the tissue samples were checked for visible fluorescence during the navigation-guided stereotactic biopsy with a sterile microscope. In each sample the observed fluorescence signal was documented. Additionally, the tissue samples were investigated ex-vivo by FLIM for detection of PpIX accumulation. In each case, a histopathological diagnosis was established according to the WHO classification of CNS tumors. Results A total number of 20 tissue samples could be retrieved in 16 patients with suspected brain tumors. The biopsy with assistance of 5-ALA was feasible in all patients and no relevant side effects occurred. Visible PpIX fluorescence could be observed in 75% of cases. In contrast, 25% of samples did not show visible fluorescence. In one specimen, no fluorescence signal could be evaluated as the sample was covered by too much blood. However, significant accumulation of PpIX could be detected by FLIM in all samples in which evaluation was possible (n=19). A final histopathological diagnosis was feasible in all patients. Conclusion Fluorescence Lifetime Imaging is a promising new technique for improved detection of brain tumor tissue during navigation-guided biopsies. Thus, this new technique might lead in future to reduced operating times and complication rate by minimizing the cases that need serial biopsies or intraoperative histopathology.

Tumour Incidence in Dogs in Germany: a Retrospective Analysis of 109,616 Histopathological Diagnoses (2014–2019)

Characterization of a tumour entity is based on the precise histopathological diagnosis taking into account the signalment of the diseased animal. The present study is a comprehensive, up-to-date statistical investigation on the type, frequency and breed distribution of neoplasia in dogs in Germany. The histopathological datasets of 109,616 German canine tissue samples (2014-2019) were processed and statistically examined in retrospect. Non-neoplastic diseases were found in 38,650 samples (35.3%) and 70,966 neoplasms (64.7%) were diagnosed. The most common neoplasms were mammary tumours (21.9%), benign epithelial skin tumours (15.4%), mast cell tumour (9.7%), histiocytoma (7.0%), soft tissue sarcoma (5.8%), lipoma (5.8%), melanocytic tumours (5.2%) and odontogenic tumours (4.7%). In general, Beagles, Magyar Vizslas, Boxers, Schnauzers, Spaniels, French Bulldogs and Golden Retrievers had an increased risk of neoplasia (odds ratio 1.17-1.46; all: P ≤0.001) compared with crossbreed dogs. In particular, Boxers, Golden Retrievers, Rottweilers and Schnauzers were often affected by malignant neoplasms, whereas some breeds (eg, West Highland White Terrier, Magyar Vizsla, Chihuahua, Dachshund and Yorkshire Terrier) were frequently affected by numerous benign tumour types. Despite the known risk of haemangiosarcoma in German Shepherd Dogs, other malignant tumours were rare in this breed. Depending on the type of tumour, some purebred dog breeds can have an increased, reduced or identical risk for certain neoplasms compared with crossbreeds. Discussion of breed predispositions to tumour diseases must therefore be conducted critically and with a view to clinical relevance.

Impact of timing and precision of histopathological diagnosis on outcomes of patients with Burkitt lymphoma and high-grade B-cell lymphoma.

Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL) are aggressive B-cell non-Hodgkin lymphomas (B-NHL) with a generally favorable prognosis after immunochemotherapy. The outcome of BL is superior to DLBCL. In 2016, a distinct group of lymphomas displaying characteristics of both BL and DLBCL (high grade B-cell lymphoma, HGBL) was introduced into the WHO classification. Histopathological discrimination of BL, DLBCL, and HGBL may be challenging. Data on the frequency of histopathological difficulties resulting in revision of the final diagnosis of BL/DLBCL/HGBL and its impact on the prognosis are limited. We assessed histopathological features and clinical outcomes of 66 patients with suspected diagnosis of BL at the reporting institution between 2010 and 2020. The median age was 51 years (range 19-82) and final histopathological diagnosis revealed BL (n=40), DLBCL (n=12), or HGBL (n=14). Patients with DLBCL and HGBL were either treated with DLBCL-directed (83.3% and 35.7%) or BL-directed (16.7% and 64.3%) protocols. Patients in whom diagnosis was revised from DLBCL to BL after initiation of DLBCL-directed treatment had a significantly inferior progression-free survival (PFS) than patients initially diagnosed with BL (p=0.045), thus resembling rather the prognosis of DLBCL/HGBL. There was no difference between patients with DLBCL and HGBL, respectively, regarding PFS and OS (p=0.38 and p=0.27). These results suggest that timely and precise histopathological diagnosis as well as reference histopathological review of the underlying lymphoma is critical to determine up-front treatment strategies. Consequently, selection of more aggressive treatment protocols in case of difficulties with discrimination between DLBCL/HGBL/BL may be a reasonable approach.

Frameless robot-assisted stereotactic biopsies for lesions of the brainstem-a series of 103 consecutive biopsies.

Targeted treatment for brainstem lesions requires above all a precise histopathological and molecular diagnosis. In the current technological era, robot-assisted stereotactic biopsies represent an accurate and safe procedure for tissue diagnosis. We present our center's experience in frameless robot-assisted biopsies for brainstem lesions. We performed a retrospective analysis of all patients benefitting from a frameless robot-guided stereotactic biopsy at our University Hospital, from 2001 to 2017. Patients consented to the use of data and/or images. The NeuroMate® robot (Renishaw™, UK) was used. We report on lesion location, trajectory strategy, histopathological diagnosis and procedure safety. Our series encompasses 96 patients (103 biopsies) treated during a 17years period. Mean age at biopsy: 34.0years (range 1-78). Most common location: pons (62.1%). Transcerebellar approach: 61 procedures (59.2%). Most common diagnoses: diffuse glioma (67.0%), metastases (7.8%) and lymphoma (6.8%). Non conclusive diagnosis: 10 cases (9.7%). After second biopsy this decreased to 4 cases (4.1%). Overall biopsy diagnostic yield: 95.8%. Permanent disability was recorded in 3 patients (2.9%, all adults), while transient complications in 17 patients (17.7%). Four cases of intra-tumoral hematoma were recorded (one case with rapid decline and fatal issue). Adjuvant targeted treatment was performed in 72.9% of patients. Mean follow-up (in the Neurosurgery Department): 2.2years. Frameless robot-assisted stereotactic biopsies can provide the initial platform towards a safe and accurate management for brainstem lesions, offering a high diagnostic yield with low permanent morbidity.

New Frontiers for Molecular Pathology.

Lung cancer remains a serious oncological problem worldwide. The delayed diagnosis and a prevalence of advanced stages in up to 70% of cases at recognition are still observed. Thanks to targeted therapies and immunotherapy a significant progress in achieving prolonged survival in some lung cancer patients is reported. A precise histopathological diagnosis, especially the recognition of adenocarcinoma, and a progress in the methods of clinical staging underlie the proper qualification of patients for a tailored therapy. The deep molecular characteristics of lung cancer in liquid biopsy, for example blood, bronchoalveolar lavage fluid (BALF), cell suspension from needle aspirates, are currently available. The molecular characteristic has recently been extended with molecular aberrations of BRAF, KRAS, MET, ERBB2, RET, NTRK next to the well-known EGFR mutations and ALK, ROS-1 relocation. The present paper discusses the usefulness of adequate pathological methods and molecular testing for the identification of a broad spectrum of predictive biomarkers for a molecular-directed lung cancer therapy. Immunotherapy with immune checkpoint inhibitors (ICIs) is approved in the first line therapy of advanced non-small-cell lung cancer. To date only PD-L1 expression on tumor cells has been found to be a marker of response to ICIs. The efficacy of ICIs as well as the susceptibility to immune-related adverse events are highly individual, so immune biomarkers are widely investigated. The candidates for predictive factors for ICIs immunotherapy include cancer cell antigenicity, presence of regulatory/suppressory molecules on cancer cells, cancer stem cells or on exosomes, and, on the other hand, an immune status of the patient. Cancers with high immune infiltration in the tumor milieu, referred to as “hot” tumors, seem to ensure a better response to ICIs than the “cold” ones. BALF analysis may replace cancer tissue examination, which is of limited access in advanced stages, for the recognition of the nature of immune response in the tumor environment. Tumor mutational burden (TMB) was shown to correlate with a good response to ICIs, especially when combined with other anticancer therapies. The present paper demonstrates the results of recent studies on lung cancer characteristics which bring us closer to the definition of useful prognostic/predictive factors.

Fine needle aspiration cytology for parotid neoplasms: risk of malignancy through inconclusive results and lower grade tumors.

Fine needle aspiration cytology (FNAC) is a commonly performed procedure for parotid masses, although its accuracy in detecting malignancies widely varies through different series. We evaluated our single-center cohort of parotidectomies to highlight possible limitations of preoperative FNAC. Seven hundred and eighteen consecutive patients submitted to parotid surgery at San Raffaele Scientific Institute (Milan) were retrospectively evaluated (2002-2018). Five hundred and fifty four FNAC were analyzed. FNAC accuracy was assessed with and without inclusion of "inconclusive" results. The peculiar role of lower grade primary parotid cancers was investigated. FNAC reports were "diagnostic" in 502 cases (90.4%) and "inconclusive" in 52 (9.6%). Histopathology revealed 488 benign lesions (88.1%) and 66 malignancies (11.9%). FNAC sensitivity, specificity, PPV, NPV and accuracy in detecting malignancies were 59%, 99%, 89%, 95%, and 95%, respectively. Sensitivity fell to 48%, when "inconclusive" FNAC was computed. Within 66 parotid cancers, FNAC could discriminate malignancy in 32 cases (48.5%), provide proper grading in 21 (31.8%), and precise histopathological diagnosis in 15 (22.7%). Malignancy was more likely in patients with "inconclusive" FNAC than in those with "diagnostic" cytologies (23.1% vs 10.8%, p = 0.003). Low-intermediate-grade primary parotid cancers were associated to a higher rate of FNAC failure in comparison with high-grade ones (86.4% vs 19.0%; p < 0.001). FNAC is an important tool for preoperative assessment of parotid masses, though its sensitivity in detecting malignancy remains poor. "Inconclusive" FNAC results could further jeopardize FNAC accuracy and should elicit resorting to additional tests, especially when a lower grade parotid cancer is suspected.

A Correlation between Histochemical Patterns of Connective Tissue Fibers and AgNORs in Breast Lesions

Background: The precise histopathologic diagnosis of a breast lesion is the first step towards the most appropriate inclusive patient’s management. The aim of this study was to evaluate the correlation between histochemical patterns of connective tissue fibers and NORs in breast lesions. Methodology: Patients with breast cancer (n = 25) were ascertained as the case group, and those with benign breast lesions were ascertained as a control group (n = 25). Histochemical evaluations of elastic fibers, reticular fibers and mean AgNORs count were performed for all study subjects. Results: Elastic fibers intensity was brought into being lessening in benign lesions and upturns in the direction of malignant lesions. The intensity of elastic fibers was found to intensify with rises of neoplastic changes in breast cancer and this was found to be statistically significant P < 0.001. Mean AgNORs counts displayed increased clusters among malignant cases equated to benign ones. Mean AgNORs count significantly increased with neoplastic proliferation P < 0.005. Conclusion: Demonstration of connective tissue fibers (particularly elastic fibers) can strength the diagnostic evidence for conventional histopathology diagnosis. Mean AgNORs count can merge as an important quantitative marker in breast cancer diagnosis.

Neonatal Mucormycosis with Gastrointestinal and Cutaneous involvement

Mucormycosis of the gastrointestinal tract is a rare fungal infection of neonates. 48-hours-old term neonate presented with intestinal obstruction and perforation. No significant risk factors were present. Histopathological examination of the resected gangrenous bowel revealed mucormycosis. Cutaneous involvement due to systemic spread led to dermal necrosis in toes. Though cutaneous lesions responded promptly to antifungal therapy, gastrointestinal manifestations required multiple antifungal therapy for prolonged period apart from surgical debridement. Precise histopathological diagnosis and early appropriate therapy can prevent dismal outcomes in neonatal mucormycosis.

CD138-positive plasmacytoid urothelial carcinoma of urinary bladder with focal micropapillary features

Both the plasmacytoid and micropapillary types of urothelial carcinoma of the urinary bladder are uncommon, distinct clinical and pathological findings. To date, several reports in the English medical literature have been published on either of these variants. CD138 is commonly used as a marker for tumors of plasma cell origin. However, few authors have described positive immunoreactivity of plasmacytoid cells in urothelial carcinoma. Mixed histological differentiation is thought to be a phenotype of locally aggressive and advanced urothelial carcinoma. Therefore, a precise histopathological diagnosis should be made and awareness of all the entities is crucial. We report a case of CD138-positive plasmacytoid urothelial carcinoma of the bladder with focal micropapillary features. To our knowledge this is the first case of these two rare subtypes of urothelial carcinoma combined in a single cystectomy specimen.

Spontaneous ventilation anesthesia combined with uniportal and tubeless thoracoscopic lung biopsy in selected patients with interstitial lung diseases.

The current guidelines emphasize the significant role of video-assisted thoracic surgical lung biopsy (VATS-LB) for a definite diagnosis of interstitial lung diseases (ILD), but they also encourage physicians to maintain the balance between the surgical benefits as well as risks. Both spontaneous ventilation video-assisted thoracic surgery (VATS) and uniportal VATS have emerged as remarkable progresses in VATS. We combined these two types of VATS and refined them to uniportal spontaneous ventilation VATS without urinary catheterization and chest tube drainage [uniportal and tubeless VATS (UT-VATS)] to perform LB in selected patients with ILD. From January 2014 to May 2015, 43 patients were included in the study. The surgical data was retrospectively analyzed. The mean diffusion capacity for carbon monoxide (DLCO) of patients was 57.6%±13.0%, forced vital capacity (FVC) was 73.1%±17.0%. There was no 30-day mortality. No patient required a switch to intubated anesthesia. The mean age was 49.6±10.7 years. The general median operative duration was 22±5 minutes, with 25±3 minutes for multiple specimens and 15±2 minutes for single specimen, respectively. Intra-operative conversion to 2-portal VATS followed by chest tube drainage and urinary catheterization occurred in 3 (7.0%) patients due to extensive pleural adhesion, and postoperative chest tube insertion was documented in 1 (2.3%) patient due to subcutaneous emphysema. No postoperative mechanical ventilation was noted. Precise histopathological diagnosis was achieved in 38 (88.4%) patients. Uniportal and tubeless thoracoscopic LB using spontaneous ventilation anesthesia can be considered a feasible and safe operation method for selected patients with ILD.

“Two is not enough” – Impact of the number of tissue samples obtained from stereotactic brain biopsies in suspected glioblastoma

ObjectiveStereotactic procedures are performed in many neurosurgical departments in order to obtain tumor tissue from brain lesions for histopathological evaluation. Biopsies can be performed frame-guided and frame less. Some departments use a biopsy needle (cylinder probe), others a forceps for repetitive smaller tissue samples. Although the applied techniques are somehow different, it is still unclear how many tissue samples have to be taken to establish reliably a final diagnosis based on histopathological and genetic examinations. Only precise histopathological diagnosis results in adequate therapy. MethodsWe included 43 consecutive patients who underwent stereotactic biopsy of a suspected glioblastoma between 02/2013 and 07/2015. All patients showed contrast enhancing tumors in the MRI.The patients underwent stereotactic biopsy with the Leksell frame attached to their head. All stereotactic procedures were performed in the presence of a neuropathologist. Target and Entry Points were calculated with BrainLab iplan software (BrainLab iplan 1.0, Munich, Germany). First the two samples 5mm before the Target (pre-target) and the “Targetpoint” itself were analyzed (group 1), then a histopathological evaluation of all samples was performed (group 2). ResultsMean number of extracted samples was 14. Using classical hematoxylin-eosin stainings, in group 1 histopathological diagnosis was correct in only 30 cases accounting for 73%. Contrariwise a final diagnosis was made in 100% in group 2. ConclusionIf only two tissue samples were evaluated in this group of patients with suspected glioblastoma, a correct diagnosis was possible in only 73% of the cases. We conclude that two samples are not enough to establish a final diagnosis even in a subgroup of suspected glioblastoma.

Problematic Differential Diagnoses in Paranasal Sinus Tumor Histopathology

The sinonasal tract (paranasal sinuses and nasal cavity) is a particularly challenging anatomic subsite for surgical pathologists to evaluate. The stakes for the patient are high, because radically different treatment decisions are entirely dependent on a precise histopathologic diagnosis. Unfortunately, pitfalls abound in dealing with these neoplasms. This manuscript serves as an updated review of three specific differential diagnoses for tumors encountered in the sinonasal tract: the glandular proliferation, the inverted squamous neoplasm, and the small round blue cell tumor. An awareness of these challenging differential diagnoses coupled with a careful diagnostic approach will allow pathologists to arrive at the correct diagnosis.

Diagnostic Accuracy of Mucosal Biopsy versus Endoscopic Mucosal Resection in Barrett's Esophagus and Related Superficial Lesions.

Background. Endoscopic surveillance for early detection of dysplastic or neoplastic changes in patients with Barrett's esophagus (BE) depends usually on biopsy. The diagnostic and therapeutic role of endoscopic mucosal resection (EMR) in BE is rapidly growing. Objective. The aim of this study was to check the accuracy of biopsy for precise histopathologic diagnosis of dysplasia and neoplasia, compared to EMR in patients having BE and related superficial esophageal lesions. Methods. A total of 48 patients with previously diagnosed BE (36 men, 12 women, mean age 49.75 ± 13.3 years) underwent routine surveillance endoscopic examination. Biopsies were taken from superficial lesions, if present, and otherwise from BE segments. Then, EMR was performed within three weeks. Results. Biopsy based histopathologic diagnoses were nondysplastic BE (NDBE), 22 cases; low-grade dysplasia (LGD), 14 cases; high-grade dysplasia (HGD), 8 cases; intramucosal carcinoma (IMC), two cases; and invasive adenocarcinoma (IAC), two cases. EMR based diagnosis differed from biopsy based diagnosis (either upgrading or downgrading) in 20 cases (41.67%), (Kappa = 0.43, 95% CI: 0.170–0.69). Conclusions. Biopsy is not a satisfactory method for accurate diagnosis of dysplastic or neoplastic changes in BE patients with or without suspicious superficial lesions. EMR should therefore be the preferred diagnostic method in such patients.

Intraoperative visualization of brain tumors with 5-aminolevulinic acid-induced fluorescence

Precise histopathological diagnosis of brain tumors is essential for the correct patient management. Furthermore, complete resection of brain tumors is associated with an improved patient prognosis. However, histopathological undergrading and incomplete tumor removal are not uncommon, especially due to insufficient intra-operative visualization of brain tumor tissue. The fluorescent dye 5-aminolevulinic acid (5-ALA) is currently applied for fluorescence-guided resections of high-grade gliomas. The value of 5-ALA-induced protoporphyrin (PpIX) fluorescence for intra-operative visualization of other tumors than high-grade gliomas remains unclear. Within the frame of this thesis, we found a significantly higher rate of complete resections of our high-grade gliomas as compared to control cases by using the newly established 5-ALA fluorescence technology at our department. Additionally, we showed that MRI spectroscopy-based chemical shift imaging (CSI) is capable to identify intratumoral high-grade glioma areas (= anaplastic foci) during navigation guided resections to avoid histopathological undergrading. However, the accuracy of navigation systems with integrated pre-operative imaging data such as CSI declines during resections due to intra-operative brainshift. In two further studies, we found that 5-ALA induced PpIX fluorescence is capable as a novel intra-operative marker to detect anaplastic foci within initially suspected low-grade gliomas independent of brainshift. Finally, we showed that the application of 5-ALA is also of relevance in needle biopsies for intra-operative identification of representative brain tumor tissue. These data indicate that 5-ALA is not only of major importance for resection of high-grade gliomas, but also for intra-operative visualization of anaplastic foci as well as representative brain tumor tissue in needle biopsies unaffected by brainshift. Consequently, this new technique might become a novel standard in brain tumor surgery that optimizes the patient management and improves the patient prognosis by maximizing the extent of tumor resection and enabling a precise histopathological tumor diagnosis.

5-Aminolevulinic Acid Induced Fluorescence Is a Powerful Intraoperative Marker for Precise Histopathological Grading of Gliomas with Non-Significant Contrast-Enhancement

BackgroundIntraoperative identification of anaplastic foci in diffusely infiltrating gliomas (DIG) with non-significant contrast-enhancement on MRI is indispensible to avoid histopathological undergrading and subsequent treatment failure. Recently, we found that 5-aminolevulinic acid (5-ALA) induced protoporphyrin IX (PpIX) fluorescence can visualize areas with increased proliferative and metabolic activity in such gliomas intraoperatively. As treatment of DIG is predominantely based on histopathological World Health Organisation (WHO) parameters, we analyzed whether PpIX fluorescence can detect anaplastic foci according to these criteria.MethodsWe prospectively included DIG patients with non-significant contrast-enhancement that received 5-ALA prior to resection. Intraoperatively, multiple samples from PpIX positive and negative intratumoral areas were collected using a modified neurosurgical microscope. In all samples, histopathological WHO criteria and proliferation rate were assessed and correlated to the PpIX fluorescence status.ResultsA total of 215 tumor specimens were collected in 59 patients. Of 26 WHO grade III gliomas, 23 cases (85%) showed focal PpIX fluorescence, whereas 29 (91%) of 33 WHO grade II gliomas were PpIX negative. In intratumoral areas with focal PpIX fluorescence, mitotic rate, cell density, nuclear pleomorphism, and proliferation rate were significantly higher than in non-fluorescing areas. The positive predictive value of focal PpIX fluorescence for WHO grade III histology was 85%.ConclusionsOur study indicates that 5-ALA induced PpIX fluorescence is a powerful marker for intraoperative identification of anaplastic foci according to the histopathological WHO criteria in DIG with non-significant contrast-enhancement. Therefore, application of 5-ALA optimizes tissue sampling for precise histopathological diagnosis independent of brain-shift.

Automation Highlights from the Literature

Automation Highlights from the Literature

Diagnostic segregation of human brain tumours using Fourier-transform infrared and/or Raman spectroscopy coupled with discriminant analysis

The most common initial treatment received by patients with a brain tumour is surgical removal of the growth. Precise histopathological diagnosis of brain tumours is to some extent subjective. Furthermore, currently available diagnostic imaging techniques to delineate the excision border during cytoreductive surgery lack the required spatial precision to aid surgeons. We set out to determine whether infrared (IR) and/or Raman spectroscopy combined with multivariate analysis could be applied to discriminate between normal brain tissue and different tumour types (meningioma, glioma and brain metastasis) based on the unique spectral "fingerprints" of their biochemical composition. Formalin-fixed paraffin-embedded tissue blocks of normal brain and different brain tumours were de-waxed, mounted on low-E slides and desiccated before being analyzed using attenuated total reflection Fourier-transform IR (ATR-FTIR) and Raman spectroscopy. ATR-FTIR spectroscopy showed a clear segregation between normal and different tumour subtypes. Discrimination of tumour classes was also apparent with Raman spectroscopy. Further analysis of spectral data revealed changes in brain biochemical structure associated with different tumours. Decreased tentatively-assigned lipid-to-protein ratio was associated with increased tumour progression. Alteration in cholesterol esters-to-phenylalanine ratio was evident in grade IV glioma and metastatic tumours. The current study indicates that IR and/or Raman spectroscopy have the potential to provide a novel diagnostic approach in the accurate diagnosis of brain tumours and have potential for application in intra-operative diagnosis.