Endosalpingiosis in Axillary Lymph Nodes: A Possible Pitfall in the Staging of Patients With Breast Carcinoma

Cadherin-16 (CDH16) immunohistochemistry: a useful diagnostic tool for renal cell carcinoma and papillary carcinomas of the thyroid

Cadherin-16 (CDH16) plays a role in the embryonal development in kidney and thyroid. Downregulation of CDH16 RNA was found in papillary carcinomas of the thyroid. To determine the expression of CDH16 in tumors and to assess the diagnostic utility a tissue microarray containing 15,584 samples from 152 different tumor types as well as 608 samples of 76 different normal tissue types was analyzed. A membranous CDH16 immunostaining was predominantly seen in thyroid, kidney, cauda epididymis, and mesonephric remnants. In the thyroid, CDH16 staining was seen in 100% of normal samples, 86% of follicular adenomas, 60% of follicular carcinomas, but only 7% of papillary carcinomas (p < 0.0001). CDH16 positivity was frequent in nephrogenic adenomas (100%), oncocytomas (98%), chromophobe (97%), clear cell (85%), and papillary (76%) renal cell carcinomas (RCCs), various subtypes of carcinoma of the ovary (16-56%), various subtyped of carcinomas of the uterus (18-40%), as well as in various subtypes of neuroendocrine neoplasms (4-26%). Nineteen further tumor entities showed a weak to moderate CDH16 staining in up to 8% of cases. Our data suggest CDH16 as a potential diagnostic marker-as a part of a panel-for the identification of papillary carcinomas of the thyroid, nephrogenic adenomas, and the distinction of renal cell tumors from other neoplasms.

Cutaneous endosalpingiosis arising from C-section scar: A case report with review of literature

Endosalpingiosis is a pathologic phenomenon in which non-neoplastic fallopian tube epithelium implants in ectopic locations. It is an uncommon and poorly understood condition, with most cases occurring within the abdominopelvic cavity. Cutaneous presentations of endosalpingiosis are even more rare, with only six cases described in international literature to-date. This report describes an additional case of cutaneous endosalpingiosis. The lesion arose within the scar tissue of a Pfannenstiel incision from 4 years prior in a 24-year old, previously healthy African American female. Punch biopsy of the lesion revealed a cystic mass lined by PAX8⁺ ciliated columnar cells and a surrounding fibrotic stroma with focal CD10-positivity, consistent with a histopathologic diagnosis of endosalpingiosis. In addition, this report provides a comprehensive review of the other documented cases of cutaneous endosalpingiosis, as well as the proposed pathogenesis, histopathologic and clinical features, and potential treatment avenues for this unique clinical entity.

Intraoperative Appearance of Endosalpingiosis: A Single-Center Experience of Laparoscopic Findings and Systematic Review of Literature

Background: Endosalpingiosis is assumed to be the second most common benign peritoneal pathology after endometriosis in women. Although recent studies indicate a significant association with gynecologic malignancies, many underlying principles remain unclear. This work aimed to systematically describe the intraoperative appearance of endosalpingiosis. Methods: Data and intraoperative videos of patients with histologically verified endosalpingiosis were retrospectively reviewed. The main outcome measures were macroscopic phenotype and anatomical distribution. Additionally, a systematic review searching PubMed (Medline) and Embase was conducted. Results: In the study population (n = 77, mean age 40.2 years (SD 16.4)), the mean size of lesions was 3.6 mm and the main visual pattern was vesicular (62%). The most frequent localization was the sacrouterine ligaments (24.7%). In the systematic review population (n = 1174 (210 included studies overall), mean age 45.7 years (SD 14.4)), there were 99 patients in 90 different studies with adequate data to assess the appearance of the lesions. The mean size of the lesions was 48.5 mm, mainly with a cystic visual pattern (49.5%). The majority of the lesions affected the ovaries (23.2%), fallopian tubes (20.4%), or lymph nodes (18.5%). Comparing this study to the literature population, the main differences concerned the size (p < 0.001) and main visual patterns (p < 0.001) of lesions. Conclusions: The usual intraoperative findings of endosalpingiosis appeared less impressive than described in the literature. In our study population, lesions of a few millimeters in size with a vesicular appearance were mostly seen, most frequently in the sacrouterine ligament area. Intraoperative recognition by the gynecologic surgeon and histologic diagnosis should play an important role in further understanding this entity, scientifically and clinically.

Update on sentinel node pathology in breast cancer

Pathologic examination of the sentinel lymph nodes (SLNs) in patients with breast cancer has been impacted by the publication of practicing changing trials over the last decade. With evidence from the ACOSOG Z0011 trial to suggest that there is no significant benefit to axillary lymph node dissection (ALND) in early-stage breast cancer patients with up to 2 positive SLNs, the rate of ALND, and in turn, intraoperative evaluation of SLNs has significantly decreased. It is of limited clinical significance to pursue multiple levels and cytokeratin immunohistochemistry to detect occult small metastases, such as isolated tumor cells and micrometastases, in this setting. Patients treated with neoadjuvant therapy, who represent a population with more extensive disease and aggressive tumor biology, were not included in Z0011 and similar trials, and thus, the evidence cannot be extrapolated to them. Recent trials have supported the safety and accuracy of sentinel lymph node biopsy (SLNB) in these patients when clinically node negative at the time of surgery. ALND remains the standard of care for any amount of residual disease in the SLNs and intraoperative evaluation of SLNs is still of value for real time surgical decision making. Given the potential prognostic significance of residual small metastases in treated lymph nodes, as well as the decreased false negative rate with the use of cytokeratin immunohistochemistry (IHC), it may be reasonable to maintain a low threshold for the use of cytokeratin IHC in post-neoadjuvant cases. Further recommendations for patients treated with neoadjuvant therapy await outcomes data from ongoing clinical trials. This review will provide an evidence-based discussion of best practices in SLN evaluation.

Endocervicosis in an Intramammary Lymph Node

Benign müllerian inclusions are frequently encountered within infra-diaphragmatic locations such as pelvic lymph nodes, bladder, cervix and vagina. Supra-diaphragmatic müllerian inclusions, especially endocervicosis, are exceedingly rare. We report a case of endocervicosis within an intramammary lymph node in a 49-year-old woman. To the best of our knowledge, this is the second reported case.

Current concepts of ectopic nodal inclusions with special emphasis on nodal nevi

Nodal inclusions of ectopic tissue within lymph nodes are seen comparatively often in dermatopathology and general pathology. Glandular and nonglandular epithelium, as well as melanocytic nevi can be observed within lymph nodes and represent mostly incidental findings without any relevance. The main challenge in reporting these morphologic features is to differentiate such benign inclusions from metastatic settlements of distinct organ tumors. As sentinel node biopsy and lymph node dissection have become standard procedure in clinical oncology and have an immense clinical impact, the correct evaluation of these nodal inclusions is indispensable to avoid undertreatment or overtreatment of patients. In addition, the genesis of these inclusions has not yet been satisfactorily clarified. Two concepts have been laid out: the theory of benign metastases and the migration arrest theory. However, neither theory has so far been able to answer the following questions: Why do we find more nodal nevi in patients with melanoma who had a sentinel node biopsy than in patients without melanoma, and why do we not find nodal nevi in deep visceral lymph nodes? We present a comprehensive review of the current knowledge on nodal inclusions, proposing a concept for the pathogenesis of nodal nevi, to answer these questions.

Detection and prognostic significance of isolated tumor cells and micrometastases in pelvic lymph nodes of patients with early ovarian clear cell carcinoma

BACKGROUND/PURPOSE

Ovarian clear cell carcinoma (OCCC) accounts for approximately 18% of all epithelial ovarian malignancies in Taiwan and portends a poor prognosis. Here, we sought to investigate whether immunohistochemistry with an anti-pan-cytokeratin antibody cocktail (AE1/AE3) can be used as an adjunct to hematoxylin and eosin (H&E) staining for improving the detection of isolated tumor cells (ITCs) and micrometastasis to pelvic lymph nodes (LNs). We also assessed whether these lesions may predict disease recurrence.

METHODS

Pelvic lymphadenectomy specimens were obtained from 197 patients with stage 1 OCCC who had undergone surgery between 2000 and 2018 from Linkou and Kaohsiung Chang Gung Memorial Hospital. Immunohistochemical staining with AE1/AE3 was applied to a total of 1186 slides. Clusters of metastatic tumor cells, detected immunohistochemically, were classified as ITCs (clusters with diameters of ≤0.2 mm) or micrometastases (tumor cell clusters of >0.2 but ≤2.0 mm). We also assessed the diameter of metastases in patients with positive lymph nodes (stage IIIA1, n = 3, 7 positive nodes).

RESULTS

Clusters with a positive AE1/AE3 staining were identified in five (2.53%) of the 197 patients (ITCs, n = 3; micrometastasis, n = 2). Four patients had no evidence of disease recurrence but a patient recurred at follow-up. Metastatic foci of patients with stage IIIA1 disease were all >2.0 mm in size.

CONCLUSION

Immunohistochemical staining with AE1/AE3 can identify micrometastasis or ITCs in LNs missed on routine H&E staining. The role of micrometastasis in predicting recurrent OCCC and implementing on treatment strategies requires further investigation.

Endosalpingiosis Is Negative for GATA3

CONTEXT.—

Endosalpingiosis is a benign Müllerian inclusion that can mimic metastatic low-grade mammary carcinoma, particularly when encountered in axillary lymph nodes excised for breast cancer staging. Immunohistochemistry can be useful in histologically ambiguous cases, and a targeted immunopanel should include a marker of gynecologic tract origin and a marker of mammary origin. GATA3 is a sensitive immunomarker for breast carcinoma, but the immunoreactivity of GATA3 in endosalpingiosis has not been systematically evaluated.

OBJECTIVE.—

To evaluate whether GATA3 immunohistochemistry could be used to differentiate endosalpingiosis from metastatic mammary carcinoma.

DESIGN.—

Whole slide sections of 15 cases of endosalpingiosis involving nonneoplastic tissues were subjected to GATA3 immunohistochemistry. Nuclear GATA3 labeling was scored as percentage and intensity labeling, with any labeling considered positive; GATA3 labeling was recorded in all cells present in the sections.

RESULTS.—

Half (47%, n = 7 of 15) of the endosalpingiosis cases involved lymph nodes (2 axillary, 5 pelvic) and half (53%, n = 8 of 15) involved pelvic organs or soft tissue (3 myometrial, 2 paratubal, 2 periadnexal soft tissue, and 1 pelvic sidewall). GATA3 immunohistochemistry was negative in all cases of endosalpingiosis, with intact, positive control labeling in lymphocytes. The benign fallopian tube epithelium present on the sections of paratubal endosalpingiosis displayed focal (<5%), weak labeling for GATA3, specifically within the ciliated and secretory cells.

CONCLUSIONS.—

These findings support the diagnostic utility of GATA3 immunohistochemistry and its use in a targeted immunopanel to resolve the differential diagnosis of metastatic low-grade mammary carcinoma (GATA3+) and nodal endosalpingiosis (GATA3-).

[Endosalpingiosis - an Irrelevant Incidental Finding During Laparoscopy?]

Endosalpingiosis - an Irrelevant Incidental Finding During Laparoscopy? Abstract. Endosalpingiosis refers to the ectopic presence of tubal epithelium. However, this incidental finding received little attention, although it is the second most common benign peritoneal pathology in women following endometriosis. In contrast to endometriosis, endosalpingiosis shows an increase in prevalence with age beyond the menopause. Furthermore, it does not appear to be chronically inflammatory and, according to research to this date, does not cause chronic pain or infertility. Recent epidemiological and molecular pathological studies show a significantly higher incidence of ovarian and endometrial tumors in women with endosalpingiosis. These correlations have not been conclusively clarified. Generally accepted clinical recommendations for the detection of endosalpingiosis do not yet exist. In order to better understand the disease value of endosalpingiosis and its oncological correlations, this entity should be brought to the attention of surgical gynecology and involved pathology.

Epithelium Involving Bilateral Axillary Lymph Nodes: Metastasis, Misplaced, or Mullerian!

During breast cancer staging, histological evaluation of axillary sentinel lymph nodes (SLN) is usually straightforward. However, the exact characterization of a small epithelial deposit in an SLN can be challenging, especially during the frozen section examination. We report the first case of endosalpingiosis involving bilateral axillary lymph nodes. We review published literature on axillary endosalpingiosis and discuss the differential diagnosis of small epithelial deposits in an axillary SLN. Pathologists should consider benign epithelial rests and displaced epithelium as differential diagnoses for the microscopic epithelial nodal deposit, especially during the frozen section examination.

A rare case of squamous inclusion cyst in cervical lymph node

A 38-year-old man, with no history of malignancy, was found to have a 2 cm jugular lymph node, for which a lymph node tuberculosis was suspected. The specimen revealed a cystic structure lined by mature keratinizing squamous epithelium with a prominent granular cell layer consistent with a squamous inclusion cyst in a lymph node, but a metastatic squamous cell carcinoma could not be excluded. This is the first case report of a rapidly enlarging squamous inclusion cyst in a jugular lymph node. Our case demonstrates the diagnostic challenges related to a squamous inclusion cyst in cervical lymph node and serves to inform the readers to consider this lesion in the differential diagnosis for similar situations.

Concordant PET/CT and ICG positive lymph nodes in endometrial cancer: a case of mistaken identity

Endometrial carcinoma is the most common gynecological malignancy in developed countries. In early stage endometrial cancer, routine systemic pelvic lymphadenectomy showed no survival benefits and results in increased morbidity. The role of PET/CT imaging for the pre-operative detection of lymph node metastases in endometrial cancer is unclear. Sentinel lymph node (SLN) mapping may reduce the surgical staging morbidity while maintaining prognostic information of the lymph node status. Recently, indocyanine green (ICG) SLN mapping has been utilized to detect nodal metastasis in endometrial cancer. Endosalpingiosis is defined as the presence of tubal-like epithelium outside of the fallopian tube and can sometimes be misinterpreted as cancer metastasis. Here, we discuss a patient with newly diagnosed endometrial cancer who had pelvic and para-aortic lymph nodes with high glucose avidity on PET/CT, and ICG positivity on SLN mapping, suspected clinically to be metastatic adenocarcinoma, but with the pathological finding of endosalpingiosis only.

Contemporary Evaluation of Breast Lymph Nodes in Anatomic Pathology

OBJECTIVES

Management of the axilla in breast cancer patients has evolved considerably since the introduction of the sentinel lymph node (SLN) biopsy in the 1990s. Several new clinical and technological developments in the last decade warrant special consideration due to their impact on pathology practice.

METHODS

This review covers the SLN biopsy procedure, issues in the histopathologic and molecular diagnosis of the SLN, and most importantly, evidence from recent practice-changing clinical trials.

RESULTS

ACOSOG Z0011, IBCSG 23-01, and AMAROS trials have shown that early-stage breast cancer patients who have limited metastatic involvement of the SLNs do not benefit from completion axillary dissections.

CONCLUSIONS

It is not necessary for pathologists to search for all small metastases to predict non-SLN involvement, regional recurrence, or death due to disease. Processing should be designed with the goal of detecting macrometastases. Multiple levels, routine immunohistochemistry, and molecular testing are not recommended.

Ductal Carcinoma In Situ Simultaneously Involving the Breast and Epithelial Inclusions in an Ipsilateral Axillary Lymph Node

Benign cystic epithelial inclusions with squamous, glandular, or Müllerian phenotypes are known to occur in the axillary lymph nodes of patients with benign and malignant breast disease. Careful evaluation of hematoxylin and eosin-stained slides and correlation with the histologic findings in the ipsilateral breast are paramount in evaluation of suspected benign inclusions. In this case of ductal carcinoma in situ (DCIS) of the breast in a 73-year-old woman, DCIS also involved epithelial inclusions in an ipsilateral axillary lymph node. The recognition of these benign epithelial elements, and awareness that they can be involved by DCIS, is crucial to avoid the overdiagnosis of metastatic carcinoma.

Axillary Lymph Node Inclusions

Lymph node inclusions can occur in axillary lymph nodes, where they can mimic metastatic breast carcinoma. This article provides an overview of epithelial and nonepithelial lymph node inclusions, including mammary-type glandular inclusions, Mullerian-type glandular inclusions, squamous inclusions, mixed glandular-squamous inclusions, and nodal nevi. The discussion emphasizes the histologic and immunophenotypic features and differential diagnoses of each entity.

Novel rapid-immunohistochemistry using an alternating current electric field for intraoperative diagnosis of sentinel lymph nodes in breast cancer

Axillary lymph node status and pathological diagnosis of sentinel lymph nodes (SLNs) is a prognostic factor that influences management of postoperative therapy. Recent reports indicate that one-step nucleic acid amplification and hematoxylin and eosin (HE)-stained frozen sections are effective for intraoperative diagnosis of SLNs. In the present study, we report a rapid-immunohistochemical staining (R-IHC) method that enables intraoperative detection of SLN metastases within 16 min using an anti-cytokeratin antibody. This is the first report on SLN diagnosis using R-IHC in patients with breast cancer. We prospectively examined 160 dissected SLNs from 108 breast cancer patients who underwent surgery at our institute. The dissected SLNs were sectioned and conventionally stained with HE or immunohistochemically labeled with anti-cytokeratin antibody using R-IHC procedures. Intraoperative R-IHC analyses were completed within 16 min, after which diagnoses were made by two pathologists. The total time required for intraoperative diagnosis was about 20 min. In this study series, R-IHC detected four metastatic SLNs that were undetected using conventional HE staining (4/20, 20.0%). Compared with subsequent permanent diagnosis, R-IHC offered 95.2% sensitivity and 100% specificity. These findings indicate R-IHC is a clinically applicable technique that enables precise and quick intraoperative detection of micro- and macrometastasis in breast cancer.

Benign breast lesions that mimic malignancy

Many benign and reactive lesions of the breast show morphological overlap with malignant lesions. These benign mimics of malignancy often present diagnostic challenges to even the most experienced pathologists. This review focuses on several benign lesions of the breast that mimic malignant entities. For each of these lesions, we describe the key morphological and immunohistochemical features, potential diagnostic pitfalls, and our approach to arriving at the correct diagnosis.

Endosalpingiosis of Axillary Lymph Nodes: A Rare Histopathologic Pitfall with Clinical Relevance for Breast Cancer Staging

Establishment of accurate axillary lymph node status is of essential importance in determining both prognosis and the potential need for adjuvant therapy in patients with invasive breast cancer. Axillary lymph node heterotopias can in some cases result in overdiagnosis of metastatic disease. Nodal endosalpingiosis is perhaps the least commonly reported type of axially lymph node heterotopia. We herein illustrate a case in which second opinion pathologic interpretation combined with ancillary immunohistochemical studies allowed for a specific diagnosis of axillary nodal müllerian-type inclusions, confirming ypN0 staging and resulting in appropriate disease management and prognostication.

The Origin of Epithelial Neoplasms of the Ovary: An Alternative View

Several theories have been proposed to explain the origin of epithelial neoplasms of the ovary. However, most of them did not receive serious consideration until recently when it has been proposed that most ovarian neoplasms arise from the fallopian tube. In this review, we mention the different theories, we discuss in detail the fallopian tube theory, and the reasons why this theory is probably inaccurate. We are also proposing a new theory, the fere ex nihilo, based on the observation of numerous cases, old and new concept, and experimental works with animals. We believe that, most probably, ovarian epithelial neoplasms are related to hormones and the identification of these hormones will allow us not only to diagnose and treat these lethal neoplasms, but also to prevent them.

A subset of nondescript axillary lymph node inclusions have the immunophenotype of endosalpingiosis

We report 2 cases of bland, otherwise nondescript axillary lymph node inclusions that have the immunophenotype of endosalpingiosis in patients with concurrent invasive breast carcinomas. Neither inclusion demonstrated the classic morphology of endosalpingiosis with admixed ciliated and secretory cells. Rather, both cases were composed of nondescript cuboidal to columnar bland epithelial cells situated within the lymph node capsule. Whereas both inclusions labeled diffusely for estrogen receptor and lacked evidence of a myoepithelial component, both labeled diffusely for PAX8 and WT-1, which distinguished them from their corresponding concurrent primary mammary carcinomas. These findings suggest that a subset of otherwise nondescript axillary lymph node inclusions represent endosalpingiosis and highlight the utility of PAX8 and WT-1 immunohistochemistry in distinguishing these from metastatic well-differentiated ductal carcinoma.

Endocervicosis involving axillary lymph nodes: first case report

The occurence of Mullerian epithelial inclusions, especially endosalpingiosis, in pelvic and other subdiaphragmatic lymph nodes is well known. In contrast, Mullerian inclusions involving lymph nodes above the diaphragm is uncommon, although occasional cases of endosalpingiosis have been reported. We report a case of benign Mullerian inclusions of mucinous endocervical type (endocervicosis) coexistent with metastatic breast-infiltrating ductal carcinoma in 2 axillary lymph nodes. The inclusions exhibited diffuse positive staining with CK7, PAX8, CA125, and estrogen receptor and were WT1 negative. To our knowledge, this is the first report of endocervicosis involving supradiaphragmatic lymph nodes. Close morphologic examination and immunohistochemistry assists in distinguishing Mullerian inclusions from metastatic adenocarcinoma.

Endosalpingiosis in postmenopausal elderly women

In gynecology, endosalpingiosis is a benign condition in which the fallopian tube-like epithelium is found outside the fallopian tube. The thirty-four point five percent of endosalpingiosis cases have concurrent endometriosis and 40% of the endosalpingiosis group are in postmenopausal states. In contrast with endometriosis, there are no significant links between infertility, chronic pelvic pain and endosalpingiosis. The symptoms of endosalpingiosis are not yet settled. Endosalpingiosis is almost always an incidental finding; it is commonly found through microscopic examinations, and is then confirmed by pathologists for excision and biopsy. Therefore, the clinical differential diagnosis of an intramural mass is more important for clinicians when discussing further surgery with the patients. We report case of woman who has endosalpingiosis and is presented with vaginal bleeding. We first suspect the disease during physical examination. Under the impression of pelvic mass, laboratory tests and radiological images of contrast enhanced chest computer tomography are taken. Images show multisepted cystic masses in left adnexa. To rule out the pelvic mass, we executed exploratory laparotomy. Pathologic results show endosalpingiosis near the ovary section. But the endosalpingiosis, is not generally considered a pathology, and thus, no treatment is necessary.

Endosalpingiosis in Axillary Lymph Nodes Simulating Metastatic Breast Carcinoma

Intraoperative assessment of sentinel lymph nodes at time of surgical excision of primary breast carcinoma is a crucial step in the determination of cancer extent and the need for further axillary dissection. Benign epithelial inclusions in axillary lymph nodes can mimic metastatic carcinoma and are a well-known pitfall during examination of these nodes in frozen or permanent sections. Most often, these inclusions consists of heterotopic mammary glands and are familiar to the practicing pathologist. Here, however, we present a rare case of endosalpingiosis in the axillary lymph nodes of a breast cancer patient and describe our experience and effort to characterize the lesion. Simulating a metastatic focus of invasive ductal carcinoma, the glandular inclusions lacked myoepithelial cells and failed to stain with myoepithelial markers. However, consistent with a Mullerian origin, the inclusions demonstrated strong staining with PAX-8 and WT-1. Although endosalpingiotic inclusions are not uncommonly encountered in subdiaphragmatic lymph nodes, they are an extremely rare finding above the diaphragm. Pathologists must be aware of these lesions and their ability to imitate metastatic gland-forming carcinoma during frozen section or permanent examination of axillary lymph nodes.

Lymph node extramedullary hematopoiesis in breast cancer patients receiving neoadjuvant therapy: a potential diagnostic pitfall

Extramedullary hematopoiesis (EMH) develops as a compensatory mechanism associated with hematologic processes but it may occur in association with chemotherapy. Three cases of EMH arising in axillary lymph nodes following neoadjuvant therapy for breast carcinoma are reported herein. Three women ranging in age from 41 to 47 years presented with unilateral breast masses measuring 0.6 to 4.0 cm in greatest dimension and were diagnosed with infiltrating ductal carcinoma, grade III by core needle biopsies. Two of the tumors were triple negative and one was estrogen receptor positive. All patients subsequently received neoadjuvant therapy followed by lumpectomies. No residual carcinoma was identified in postchemotherapy breast resection specimens. One patient underwent a sentinel lymph node procedure, the second patient an axillary lymph node dissection, and the third patient had a core biopsy of an enlarged axillary lymph node. The patient that underwent axillary lymph node dissection had metastatic carcinoma in one of her lymph nodes. Foci of EMH consisting of myeloid, erythroid, and megakaryocytic precursors were present within the nodal parenchyma and/or subcapsular sinuses of axillary lymph nodes of all three cases. Megakaryocytes were immunoreactive with factor VIII, erythroid elements with Glycophorin and myeloid precursors with myeloperoxidase. With increasing use of neoadjuvant therapy for breast carcinoma, EMH within lymph nodes is more likely to be encountered. Hematopoietic precursors present in lymph nodes may potentially be misdiagnosed as metastatic tumor cells, particularly as lobular carcinoma or metaplastic carcinoma. Therefore, caution should be exercised when evaluating axillary lymph nodes in the clinical setting of neoadjuvant therapy for breast carcinoma.

Incidence and possible pathogenesis of sentinel node micrometastases in ductal carcinoma in situ of the breast detected using molecular whole lymph node assay

Background:

The pathogenesis of lymph node metastases in preinvasive breast cancer – ductal carcinoma in situ (DCIS) – remains controversial. The one-step nucleic acid amplification (OSNA) assay is a novel molecular method that can assess a whole node and detect clinically relevant metastases. In this retrospective cohort study, we determined the performance of the OSNA assay in DCIS and the pathogenesis of node-positive DCIS.

Methods:

The subjects consisted of 623 patients with DCIS who underwent sentinel lymph node (SN) biopsy. Of these, 2-mm-sectioned nodes were examined using frozen-section (FS) histology in 338 patients between 2007 and 2009, while 285 underwent OSNA whole node assays between 2009 and 2011. The SN-positivity rate was compared between cohorts, and the characteristics of OSNA-positive DCIS were investigated.

Results:

The OSNA detected more cases of SN metastases than FS histology (12 out of 285, 4.2% vs 1 out of 338, 0.3%). Most of the metastases were micrometastases. The characteristics of high-risk DCIS (i.e., mass formation, size, grade, and comedo) and preoperative breast biopsy (i.e., methods or time to surgery) were not valid for OSNA assay–positive DCIS.

Conclusion:

The OSNA detects more SN metastases in DCIS than FS histology. Further examination of the primary tumours and follow-up of node-positive DCIS are needed to elucidate the pathogenesis.

Clinical Implications of Micrometastasis Detection in Internal Mammary Nodes of Breast Cancer Patients

BACKGROUND: The aim of this study was to assess the efficiency of step-serial sectioning (SSS) combined with hematoxylin and eosin (H&E) and immunohistochemical (IHC) staining in detecting micrometastasis of internal mammary lymph nodes (IMLNs). PATIENTS AND METHODS: 135 IMLNs from 88 breast cancer patients were re-examined by SSS, combined with either H&E or IHC staining of the biomarkers cytokeratin-19 and epithelial membrane antigen. RESULTS: Of the 135 IMLNs, 6 nodes from 5 cases displayed 1 or more micrometastases. Histological grade and lymphovascular invasion status were significantly correlated with micrometastasis in the IMLNs (p = 0.018 and 0.001, respectively). Of the 6 nodes positive for micrometastasis, 1 node was detected by both H&E and IHC staining. The remaining 5 nodes from 4 cases showed evident tumor cells only by IHC staining. Finally 8 of the 83 patients (9.64%) without IMLN metastasis showed distant metastasis, while 2 of the 5 patients (40%) with IMLN metastasis showed distant metastasis within 28 months of operation. CONCLUSION: SSS combined with H&E and IHC staining is more efficient in detecting micrometastasis than classic routine single-slice H&E only.

A Rapidly Enlarging Squamous Inclusion Cyst in an Axillary Lymph Node following Core Needle Biopsy

A 73-year-old woman was found to have a 1.7 cm axillary mass, for which a core needle biopsy was performed. The specimen revealed fragmented squamous epithelium surrounded by lymphoid tissue consistent with a squamous inclusion cyst in a lymph node, but a metastatic squamous cell carcinoma could not be excluded. Within one month, the lesion enlarged to 5 cm and was excised. Touch preparation cytology during intraoperative consultation displayed numerous single and sheets of atypical epithelioid cells with enlarged nuclei and occasional mitoses, suggesting a carcinoma. However, multinucleated giant cells and neutrophils in the background indicated reactive changes. We interpreted the touch preparation as atypical and recommended conservative surgical management. Permanent sections revealed a ruptured squamous inclusion cyst in a lymph node with extensive reactive changes. Retrospectively, the atypical epithelioid cells on touch preparation corresponded to reactive histiocytes. This is the first case report of a rapidly enlarging ruptured squamous inclusion cyst in an axillary lymph node following core needle biopsy. Our case demonstrates the diagnostic challenges related to a ruptured squamous inclusion cyst and serves to inform the readers to consider this lesion in the differential diagnosis for similar situations.