Use of intraoperative stereomicroscopy for preventing loss of metastases during frozen sectioning of sentinel lymph nodes in breast cancer

Aims:  Optimal detection of metastases in sentinel lymph nodes (SLN) remains controversial. To determine the reliability of intraoperative frozen sections, SLN protocol with one frozen section was compared with macroscopic SLN evaluation with consecutive complete SLN embedding.
Methods and results:  SLN from 135 consecutive breast cancer patients were analysed under a sereomicroscope. Frozen sections were performed in suspicious or clearly involved SLN on cut surface. One control group ( n  = 143) underwent one intraoperative frozen section on each SLN. The second control group ( n  = 90) was subjected to stereomicroscopy and one intraoperative frozen section on each SLN. A conventional SLN protocol with cytokeratin immunohistochemistry was performed postoperatively in all cases. All groups were statistically comparable. In the study group metastases were suspected in 21 SLN (16%) under the stereomicroscope and all were confirmed histologically. The negative SLN rate was significantly lower in the study group than in the main control group (47% versus 64%, P  = 0.008), suggesting loss of metastases during frozen sections. More macrometastases were detected in the study group (30% versus 15%, P  = 0.006); there were no differences in isolated tumour cells or micrometastases. The false-negative rate was significantly lower in the control groups (29% versus 13% and 12%, P  = 0.001).
Conclusions:  Frozen sections potentially lead to loss or reduced size of metastatic deposits in SLN. Avoiding intraoperative frozen sections on grossly inconspicuous SLN may therefore be justified.     

Metastatic melanoma volume in sentinel nodes: objective stereology-based measurement predicts disease recurrence and survival

Aims:  Sentinel lymph node (SLN) status is the most important prognostic factor in intermediate thickness melanoma. The amount of metastatic disease in positive SLNs varies greatly between patients, and this tumour burden appears to influence the prognosis of node-positive patients. The aim was to use objective stereological techniques to correlate accurately total SLN tumour burden with recurrence and patient survival.
Methods and results:  SLNs from 327 patients were examined by complete step sectioning and immunohistochemistry. The total metastasis volume (TMV) of 156 positive SLNs from 99 patients (30.3%) was measured using stereological methods based on the 2D-nucleator and Cavalieri's principle. The maximum metastasis diameter was also measured. These two measurements were correlated with disease recurrence and patient survival. The mean TMV for SLN+ patients was 10.5 mm³ (median 0.05 mm³; range 0.0001–623.7 mm³). Median follow-up was 26.3 months. On multivariate analysis, TMV was an independent predictor of recurrence when corrected for primary tumour thickness ( P  = 0.001) and was a stronger prognosticator compared with the maximum metastasis diameter ( P  < 0.0001 versus P  = 0.01).
Conclusions:  Combining total step sectioning of SLNs with stereological assessment of metastases, we found metastasis volume to be a highly significant predictor of disease recurrence and survival.     

Evaluation of axillary sentinel lymph node biopsy by immunohistochemistry and multilevel sectioning in patients with breast carcinoma

BACKGROUND: Axillary lymph node dissection for evaluation of the presence or absence of metastatic disease is the single most important prognostic factor for patients with newly diagnosed primary breast cancer. Recently, sentinel lymph node (SLN) biopsy is being investigated as an alternative to the evaluation of the entire axilla. We evaluated whether the application of multilevel sectioning and immunohistochemistry in SLNs will increase the accuracy of detection of metastatic deposits. METHODS: Between October 1998 and July 1999, 38 patients with breast carcinoma (25 ductal, 5 lobular, 4 tubular, and 4 mixed ductal and lobular) underwent successful SLN biopsy followed by complete axillary node dissection. Sentinel lymph nodes were localized with a combination of isosulfan blue dye and radionuclide colloid injection. Frozen sections and permanent sections of SLNs were examined. All negative SLNs were examined for micrometastases by 3 additional hematoxylin-eosin (H&E)-stained sections and immunohistochemistry with the cytokeratins AE1/AE3. RESULTS: Sentinel lymph nodes were successfully identified surgically in 38 (93%) of 41 patients. There was a 97% correlation between the results of the frozen sections and the permanent H&E-stained sections. Twelve (32%) of 38 patients showed evidence of metastatic disease in their SLN by routine H&E staining. In 7 (58%) of 12 patients with positive nodes, the sentinel node was the only positive node. The 26 patients with negative SLN examination by H&E were further analyzed for micrometastases; 5 (19%) were found to have metastatic deposits by immunohistochemistry. Of these patients, 2 were also converted to node positive by detection of micrometastatic disease by examination of the additional H&E levels. CONCLUSIONS: Sentinel lymph nodes can be accurately identified in the axilla of breast cancer patients. Evaluation of SLNs provides reliable information representative of the status of the axilla in these patients. Immunohistochemistry and, to a lesser degree, detailed multilevel sectioning are able to further improve our ability to detect micrometastatic disease in SLNs of breast cancer patients.     

Multiparameter flow cytometry as a tool for the detection of micrometastatic tumour cells in the sentinel lymph node procedure of patients with breast cancer

AIM: To investigate whether multiparameter flow cytometry (MP-FCM) can be used for the detection of micrometastasis in sentinel lymph nodes (SLNs) in breast cancer. METHODS: Formalin fixed, paraffin wax embedded sentinel lymph nodes (n = 238) from 98 patients were analysed. For each lymph node, sections for haematoxylin and eosin (H&E) staining and immunohistochemistry (IHC) for cytokeratin (MNF116) were cut at three levels with a distance of 500 microm. The intervening material was used for MP-FCM. Cells were immunostained with MNF116, followed by an incubation with fluorescein isothiocyanate (FITC) labelled goat antimouse immunoglobulin. DNA was stained using propidium iodide. From each lymph node 100,000 cells were analysed on the flow cytometer. RESULTS: Thirty eight of the 98 patients with breast carcinoma showed evidence of metastatic disease in the SLN by one ore more of the three methods. In 37 of 38 cases where metastatic cells were seen in the routine H&E and/or IHC, more than 1% cytokeratin positive cells were detected by MP-FCM. In 24 patients, metastatic foci were more than 2 mm (macrometastasis) and in 14 these foci were smaller than 2 mm (micrometastasis). In three of these 14 cases, MP-FCM revealed positive SLNs, although this was not seen at first glance in the H&E or IHC sections. After revision of the slides, one of these three remained negative. However, MP-FCM analysis of the cytokeratin positive cells showed an aneuploid DNA peak, which was almost identical to that of the primary breast tumour. Duplicate measurements, done in 41 cases, showed a 99% reproducibility. In five of 14 patients with micrometastasis, one or two metastatic foci were found in the non-SLN. However, in 15 of 24 macrometastases multiple non-SLNs were found to have metastatic tumour. All micrometastases except for the remaining negative one mentioned above showed only diploid tumour cells, despite the fact that their primary tumours contained both diploid and aneuploid tumour cells. In primary tumours with more than 60% aneuploid cells, predominantly aneuploid macrometastasis were found, whereas diploid primary tumours only showed diploid micrometastases or macrometastases in their SLN. Aneuploid SLN macrometastases were associated with non-SLN metastases in five of seven patients, whereas diploid cases showed additional non-SLN metastases in only seven of 16 patients. CONCLUSION: In all cases, MP-FCM was sufficient to detect micrometastatic tumour cells in a large volume of lymph node tissue from SLNs. In some cases it was superior to H&E and IHC staining. Approximately 30% of SLN micrometastases are accompanied by additional non-SLN metastases. The size of the aneuploid fraction (> 60%) in the primary tumour may influence the risk of having both SLN and non-SLN metastases.     

Sentinel lymph node investigation in melanoma: detailed analysis of the yield from step sectioning and immunohistochemistry

AIMS: To evaluate in detail the extent to which step sectioning and immunohistochemical examination of sentinel lymph nodes (SLNs) in patients with melanoma reveal additional node positive patients, to arrive at a sensitive yet workable protocol for histopathological SLN examination. METHODS: The study comprised 29 patients with one or more positive SLN after a successful SLN procedure for clinical stage I/II melanoma. SLNs were lamellated into pieces of approximately 0.5 cm in size. One initial haematoxylin and eosin (H&E) stained central cross section was made for each block. When negative, four step ribbons were cut at intervals of 250 microm. One section from each ribbon was stained with H&E, and one was used for immunohistochemistry (IHC). RESULTS: When taking the cumulative total of detected metastases at level 5 as 100%, the percentage of SLN positive patients increased from 79%, 83%, 83%, 90% to 93% in the H&E sections through levels 1-5, and with IHC these values were 83%, 86%, 90%, 97%, and 100%, respectively. One of six patients in whom metastases were detected at levels 2-5 only had metastases in the subsequent additional lymph node dissection. CONCLUSIONS: Multiple level sectioning of SLNs (five levels at 250 microm intervals) and the use of IHC detects additional metastases up to the last level in melanoma SLNs. Although more levels of sectioning might increase the yield even further, this protocol ensures a reasonable workload for the pathologist with an acceptable sensitivity when compared with the published literature.     

Supervised automated microscopy increases sensitivity and efficiency of detection of sentinel node micrometastases in patients with breast cancer

AIMS: To investigate the practicality and sensitivity of supervised automated microscopy (AM) for the detection of micrometastasis in sentinel lymph nodes (SLNs) from patients with breast carcinoma. METHODS: In total, 440 SLN slides (immunohistochemically stained for cytokeratin) from 86 patients were obtained from two hospitals. Samples were selected on the basis of: (1) a pathology report mentioning micrometastases or isolated tumour cells (ITCs) and (2) reported as negative nodes (N0). RESULTS: From a test set of 29 slides (12 SLN positive patients, including positive and negative nodes), 18 slides were scored positive by supervised AM and 11 were negative. Routine examination revealed 17 positive slides and 12 negative. Subsequently, automated reanalysis of 187 slides (34 patients; institute I) and 216 slides (40 patients; institute II) from reported node negative (N0) patients showed that two and seven slides (from two and five patients, respectively) contained ITCs, respectively, all confirmed by the pathologists, corresponding to 5.9% and 12.5% missed patients. In four of the seven missed cases from institute II, AM also detected clusters of four to 30 cells, but all with a size < or = 0.2 mm. CONCLUSIONS: Supervised AM is a more sensitive method for detecting immunohistochemically stained micrometastasis and ITCs in SLNs than routine pathology. However, the clinical relevance of detecting cytokeratin positive cells in SLNs of patients with breast cancer is still an unresolved issue and is at the moment being validated in larger clinical trials.     

Rapid intraoperative immunohistochemical evaluation of sentinel lymph nodes for metastatic breast carcinoma.

OBJECTIVE: Sentinel lymph node (SLN) biopsy is an integral part of the surgical management of patients with breast cancer. Rapid immunohistochemistry (RIHC) has the potential to increase detection of metastatic carcinoma at the time of frozen section consultation. The authors assessed the accuracy and turnaround time of a newly developed RIHC method for pancytokeratin (RIHC-CK). METHODS: Sixty-six SLNs from 32 patients with breast carcinoma were examined for metastasis using the Zymed Sentinel Lymph Node Rapid IHC Kit. Intraoperative frozen sections (6 mum) of the SLNs were incubated with Zymed anti-pan-cytokeratin/HRP conjugate, diaminobenzidine (DAB), and stained with hematoxylin. Slides were ready within 8 minutes and were interpreted as positive or negative for metastatic carcinoma. Results were compared with previous intraoperative touch preparations, frozen sections, hematoxylin and eosin (Perm H&E), and AEl/3-immunostained permanent sections (Perm CK). RESULTS: Fourteen lymph nodes (19%) in 13 patients tested positive for metastatic carcinoma in Perm H&E, the gold standard. RIHC-CK had the highest sensitivity (92%) of the intraoperative tests, compared with touch preparations (64%) and frozen sections (80%). RIHC-CK showed 94% accuracy, compared with 96% (frozen section) and 93% (touch preparation). The RIHC technique took 8 minutes and was easy to perform and interpret. CONCLUSIONS: Zymed RIHC is a sensitive method for detecting breast cancer metastases in SLNs. The speed, accuracy, and ease of interpretation of the test allow for recognition of micrometastases (<2 mm) that might otherwise be undetectable by current methods of intraoperative evaluation. The prognostic significance and effect on surgical management of micrometastases in SLNs have yet to be determined.     

Pathologic evaluation of sentinel lymph nodes in colorectal carcinoma

BACKGROUND: The identification of lymph node metastases in colorectal resection specimens is necessary for accurate tumor staging. However, routine lymph node dissection by the pathologist yields only a subset of nodes removed surgically and may not include those nodes most directly in the path of lymphatic drainage from the tumor. Intraoperative mapping of such sentinel lymph nodes (SLNs) has been reported in cases of melanoma and breast cancer. We applied a similar method to cases of colorectal carcinoma, with emphasis on the pathology of the SLNs. METHODS: Eighty-three consecutive patients with colorectal carcinoma were evaluated after intraoperative injection of 1 to 2 mL of 1% isosulfan blue dye (Lymphazurin) into the peritumoral subserosa. Blue-stained lymph nodes were suture-tagged by the surgeon within minutes of the injection for identification by the pathologist, and a standard resection was performed. Designated SLNs were sectioned at 10 levels through the block; a cytokeratin immunostain (AE1) was also obtained. To evaluate the possibility that increased detection of metastases in the SLN might be solely due to increased histologic sampling, all initially negative non-SLNs in the first 25 cases were sectioned also at 10 levels. RESULTS: Sentinel lymph nodes were identified intraoperatively in 82 (99%) of 83 patients and accounted for 152 (11.9%) of 1275 lymph nodes recovered, with an average of 1.9 SLNs per patient. A total of 99 positive lymph nodes (38 positive SLNs and 61 positive non-SLNs) were identified in 34 node-positive patients. The SLNs were the only site of metastasis in 17 patients (50%), while 14 patients (41%) had both positive SLNs and non-SLNs. Three patients (9%) had positive non-SLNs with negative SLNs, representing skip metastases. In patients with positive SLNs, 91 (19%) of 474 total lymph nodes and 53 (12%) of 436 non-SLNs were positive for metastasis. In patients with negative SLNs, 8 (1%) of 801 total lymph nodes and 8 (1.2%) of 687 non-SLNs were positive for metastasis. Multilevel sections of 330 initially negative non-SLNs in the first 25 patients yielded only 2 additional positive nodes (0. 6%). All patients with positive SLNs were correctly staged by a combination of 4 representative levels through the SLN(s) together with a single cytokeratin immunostain. CONCLUSIONS: Intraoperative mapping of SLNs in colorectal carcinoma identifies lymph nodes likely to contain metastases. Focused pathologic evaluation of the 1 to 4 SLNs so identified can improve the accuracy of pathologic staging.     

Frozen section analysis of sentinel lymph nodes in patients with breast cancer does not impair the probability to detect lymph node metastases

Intra-operative frozen section analysis (FS analysis) of sentinel lymph nodes (SLNs) in patients with breast cancer can prevent a second operation for axillary lymph node dissection. In contrast, loss of tissue during FS analysis may impair the probability to detect lymph node metastases. To determine the effect of tissue loss on the probability of detection of metastases, dimensions and tissue loss resulting from intra-operative frozen section analysis were measured for 21 SLNs. In a mathematical model, the influence of tissue loss on the probability to detect metastases was calculated in relation to SLN size for various pathology protocols: an American, a widely used European, the extensive ‘Milan’ and the Dutch protocol. For median-sized SLN 11 × 8 × 5 mm (length × width × height), FS analysis led to a median loss of 680 μm (13.6%) of the height of the SLN. Irrespective of SLN size or used pathology protocol, the probability of detecting 2 mm metastases remained unchanged or even increased (0–12.8%). Moreover, the probability to detect 0.2 mm metastases increased for the majority of tested combinations of SLN size, tissue loss and used protocol. Only when combining maximum tissue loss and smallest SLN size in the Dutch protocol, or when applying the extensive Milan protocol on a median-sized SLN, the probability to detect 0.2 mm metastases decreased by 2.7% and 14.3%, respectively. Contrary to ‘common knowledge’, doing FS analysis of SLNs does not impair the probability to detect lymph node metastases.     

Mapping metastases in sentinel lymph nodes of breast cancer

Localization of metastases within the sentinel lymph nodes (SLNs) of breast cancer has not been studied. Forty SLNs from 36 patients with operable primary breast cancers were identified by means of lymphatic mapping with patent blue dye. The junction between the patent blue-stained lymphatic vessel draining the tumor and the SLN was labeled with alcian blue. Metastases within the serially sectioned SLNs were assigned to the alcian blue-labeled side, to the opposite side of the virtually halved nodes, or both. Eight SLNs were negative for metastasis. Eleven SLNs had metastases only in the blue half. Only 4 cases had larger metastases in the nonblue half. Metastases are more likely to be located in the vicinity of the inflow junction of the identifiable lymphatic draining the tumor and the SLN. This should be considered when SLNs are examined, especially when they are halved for different studies.     

Implementation of step sectioning in the examination of sentinel lymph nodes to improve the detection of micrometastases in breast cancer patients

The object of this study was to examine whether a new protocol for examination of sentinel lymph nodes (SLNs) would lead to the detection of more metastases. Sections of 1 mm would identify most SLN macrometastases, and step sections at intervals of 200-250 μm would identify most micrometastases. A total of 111 breast cancer patients who underwent the SLN procedure at St. Olavs University Hospital in Trondheim, Norway in 2008 were included in the study group. Their SLNs were processed according to a new standardized protocol with sections of 2-3 mm being step sectioned at intervals of 200-250 μm. A total of 109 breast cancer patients undergoing the SLN procedure in 2007 were used as a reference group. Metastases were found in 29% of the cases, compared with 26% in the reference group. Step sectioning of SLNs revealed metastases in five cases initially found to be negative. The metastases of the study group were smaller, with a median value of 1.25 mm compared with 4.25 mm in the reference group. Step sectioning led to the detection of metastases in SLNs initially found to be negative. The median size of the metastases was considerably smaller in the study group than in the reference group.     

The prognostic impact of M-CSF, CSF-1 receptor, CD68 and CD3 in prostatic carcinoma

Aims:  Macrophage colony-stimulating factor (M-CSF) binds to colony-stimulating factor-1 receptor (CSF-1R) and stimulates proliferation and differentiation of monocytes, macrophages and their bone marrow progenitors. M-CSF, CSF-1R, the macrophage marker CD68, and the pan T-lymphocyte marker CD3 are increased in many human cancers. Their prognostic importance in primary prostatic carcinoma has not been fully delineated. The aim was to compare the expression of M-CSF, CSF-1R, CD68 and CD3 in metastatic and non-metastatic prostatic cancer.
Methods and results:  Digital video analysis of tumour cell areas and tumour stromal areas was performed in 59 cancer specimens: 32 patients with metastases and 27 patients without metastases. Expression of M-CSF and CSF-1R was recorded as 0 (negative immunoreactivity), 1 (weak), 2 (moderate) or 3 (strong reactivity). Macrophages (CD68) and T lymphocytes (CD3) were detected as proportions of moderately or strongly immunoreactive cells. Patients with metastatic primary cancers showed higher expression of M-CSF ( P  < 0.0001, P  = 0.005), CSF-1R (both P  < 0.0001) and CD3 ( P  = 0.007, P  < 0.0001) in both tumour cell areas and tumour stromal areas, compared with the non-metastatic cancers.
Conclusion:  This study suggests that expression of M-CSF, CSF-1R and CD3 is a significant prognostic factor in primary prostatic cancers by predicting the development of metastases.     

Isolated tumor cells in the regional lymph nodes in patients with squamous cell carcinoma of the esophagus are rarely observed but often represent part of a true metastasis

The most common malignancy of the esophagus is squamous cell carcinoma (SCC) and regional lymph node metastases are an important prognostic factor. Isolated tumor cells (ITCs) are defined as single tumor cells or small clusters of tumor cells not exceeding 0.2 mm. The prognostic role of ITCs is not clear. This study aimed to determine the prevalence of ITCs in regional lymph nodes in patients with esophageal SCC and to investigate how frequently ITCs represent part of a true metastasis. Surgical specimens from 100 patients with SCC of the esophagus were included. All original H&E stained slides containing lymph nodes were reviewed by two gastrointestinal pathologists. In lymph nodes containing ITCs, additional levels were cut and stained with a H&E- and a cytokeratin stain. Areas of tumor cells that measured >0.2 mm on the deeper sections were classified as metastases. A total of 2460 lymph nodes were examined. ITCs were detected in 10 lymph nodes (0.4%) from nine patients (9%). Deeper sections revealed metastases in five out of the 10 lymph nodes (50%). ITCs in regional lymph nodes of patients with SCC of the esophagus is a rare finding compared with patients with adenocarcinoma of the esophagogastric junction. However, deeper sections often revealed metastases. Therefore, in patients with SCC of the esophagus, we recommend additional sectioning and immunohistochemical examination of lymph nodes when ITCs are detected on the first slide.     

Discrepancies in current practice of pathological evaluation of sentinel lymph nodes in breast cancer. Results of a questionnaire based survey by the European Working Group for Breast Screening Pathology

AIMS: To evaluate aspects of the current practice of sentinel lymph node (SLN) pathology in breast cancer via a questionnaire based survey, to recognise major issues that the European guidelines for mammography screening should address in the next revision. METHODS: A questionnaire was circulated by mail or electronically by the authors in their respective countries. Replies from pathology units dealing with SLN specimens were evaluated further. RESULTS: Of the 382 respondents, 240 European pathology units were dealing with SLN specimens. Sixty per cent of these units carried out intraoperative assessment, most commonly consisting of frozen sections. Most units slice larger SLNs into pieces and only 12% assess these slices on a single haematoxylin and eosin (HE) stained slide. Seventy one per cent of the units routinely use immunohistochemistry in all cases negative by HE. The terms micrometastasis, submicrometastasis, and isolated tumour cells (ITCs) are used in 93%, 22%, and 71% of units, respectively, but have a rather heterogeneous interpretation. Molecular SLN staging was reported by only 10 units (4%). Most institutions have their own guidelines for SLN processing, but some countries also have well recognised national guidelines. CONCLUSIONS: Pathological examination of SLNs throughout Europe varies considerably and is not standardised. The European guidelines should focus on standardising examination. They should recommend techniques that identify metastases > 2 mm as a minimum standard. Uniform reporting of additional findings may also be important, because micrometastases and ITCs may in the future be shown to have clinical relevance.     

Rapid immunohistochemistry of sentinel lymph nodes for metastatic melanoma

Sentinel lymph node (SLN) biopsy is performed on patients with malignant melanoma (MM) to assess the need for selective complete lymphadenectomy. Melanoma metastasis to regional lymph nodes is an important prognostic indicator in patients with MM. This study assesses the sensitivity and specificity of rapid immunohistochemistry (RIHC) in intraoperative delineation of melanoma metastasis to SLN. RIHC for S-100 protein, HMB45, and a melanoma marker cocktail (melan A, HMB45, and tyrosinase) was performed on 71 SLNs obtained from 28 patients with MM. Frozen sections (6 micro thick) on plus slides were fixed for 2 to 3 minutes in cold acetone and then stored at -70 degrees C. The EnVision kit (Dako, Carpinteria, CA) for rapid immunohistochemistry (RIHC) on frozen tissue sections was used, and the staining technique took 19 minutes. Together with preparation of the frozen sections and fixation in acetone, immunostained slides were available in approximately 25 minutes. Of the 71 SNLs examined, 7 showed melanoma metastasis in permanent sections. RIHC of frozen sections detected metastatic melanoma in 6 SLNs, with a sensitivity of 86% for HMB45 and 71% for S-100 protein and the melanoma cocktail and a specificity of 97% for HMB45 and 100% for S-100 and the melanoma cocktail. We conclude that RIHC for HMB45, S-100 protein, and the melanoma cocktail may help detect melanoma metastasis in SLN intraoperatively, leading to total lymph node dissection and obviating the need for 2 surgical procedures. Section folds and background stain can make interpretation difficult. Intraoperative time constraints require a more rapid technique. A recent consensus group has discouraged frozen-section examination of SLN.     

Intraoperative examination of the sentinel lymph node for breast carcinoma staging.

Intraoperative pathologic examination of the sentinel lymph node (SLN) draining a primary breast carcinoma allows an SLN-positive patient to undergo complete axillary lymphadenectomy as part of the same surgical procedure. However, the optimal technique for rapid SLN assessment has not been determined. We reviewed our results with imprint cytology (IC) and frozen section (FS) examination of SLNs from 278 patients. Compared with H&E-stained paraffin sections, IC and FS had an overall accuracy of 93.2%. The false-reassurance rate (false-negative results/all negative results) was 8.4%. It correctly identified 98% of macrometastases but only 28% of micrometastases. There were no false-positive results. Compared with paraffin-section cytokeratin immunohistochemistry results, the IC-FS false-reassurance rate increased to 25.8%. The false-reassurance rate decreased with smaller primary tumor size (T1 vs T2/3) and ductal type, smaller diameter of the SLN (< or = 2.0 cm), and greater pathologist experience. IC combined with 2-level FS reliably identifies SLN macrometastases but commonly fails to detect SLN micrometastases. If SLN micrometastasis is used to determine the need for further lymphadenectomy, more sensitive intraoperative methods will be needed to avoid a second operation.     

Intraoperative sentinel lymph node evaluation in patients with node-positive breast cancer status post neoadjuvant systemic therapy - An institutional experience

Recent studies have shown the feasibility and utility of sentinel lymph node (SLN) biopsy in patients with biopsy proven node-positive breast cancer after neoadjuvant chemotherapy. We reviewed our experience in intraoperative SLN evaluation in such cases and its effect on axillary management. A retrospective analysis of breast cancer patients (2015–2018) with a biopsy-proven positive axillary lymph node, who received neoadjuvant systemic therapy and underwent intraoperative SLN assessment was performed. Intraoperative SLN assessment results were compared with final pathology. Its accuracy and effect on axillary management is summarized. We identified 106 patients with positive axillary lymph node and neoadjuvant systemic therapy between the ages of 28 and 75 years who had SLN biopsy and lumpectomy (33) or mastectomy (73). Three or more SLNs were identified in 91 cases (86 %). The previously biopsied lymph node was identified as one of the sentinel lymph nodes in 93 cases (88 %). There is a high concordance rate between frozen section diagnosis and final diagnosis on sentinel lymph nodes. No false positive case and seven false negative frozen section diagnosis cases (diagnosed as negative on frozen section and positive on permanent sections) were identified. False-negative frozen section diagnosis correlated with low-volume nodal disease and obscuring tumor bed changes. Almost half of the positive lymph nodes were converted to negative after neoadjuvant chemotherapy. SLN biopsy with intraoperative frozen section evaluation after neoadjuvant systemic therapy in node-positive patients is an effective way to minimize axillary surgery.     

Diagnostic value of HMB-45 and anti-Melan A staining of sentinel lymph nodes with isolated positive cells.

Numerous immunohistochemical stains have been employed to detect metastatic melanoma in sentinel lymph node (SLN) biopsies. HMB-45 is considered by some as a specific tool to detect early metastatic melanoma (1). Occasionally, one or two isolated HMB-45-positive cells may cause complications in diagnostic interpretation. The goal of this study was to evaluate the reliability of HMB-45 staining of SLNs with sparse isolated positive cells and to compare its staining with anti-Melan A antibody. HMB-45 and anti-Melan A antibody immunostaining was performed on (Group A) 15 histologically negative SLNs excised from patients with malignant melanoma (MM) and on (Group B) 15 histologically negative SLNs excised from patients with breast carcinoma (BC). None of the patients had clinical evidence of systemic metastasis at the time of SLN biopsy. Five cutaneous biopsies with changes of postinflammatory hyperpigmentation (PIHP) were also stained with both antibodies. HMB-45 staining was repeated in all Group B SLNs after blocking endogenous biotins. Electron-microscopic studies were performed on all cases of PIHP. Isolated HMB-45-stained cells were present in 6 of 15 SLNs removed for MM; 8 of 15 for BC; and 3 of 5 cutaneous biopsies of PIHP. HMB-45 reactivity persisted after blocking endogenous biotins in 6 of 8 positive SLNs from Group B. Anti-Melan A antibody was negative in all SLNs of group A and B and in dermal melanophages of all five cases of PIHP. HMB-45 positivity was demonstrated in histologically negative SLNs and cutaneous biopsies, especially in the milieu of aggregated melanophages. Phagocytosis of premelanosomes by macrophages in the draining lymph nodes may account for isolated cell positivity and can hinder correct diagnostic interpretation. HMB-45 may not be a reliable marker for the detection of micro-metastasis of MM and requires correlation with other immunohistochemical markers, such as anti-Melan A antibody, to enhance specificity.